ORCID Profile
0000-0002-9570-9172
Current Organisation
Australian Institute of Tropical Health and Medicine
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In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Psychology | Family and Household Studies | Epidemiology | Public Health and Health Services | Epidemiology | Psychological Methodology, Design And Analysis | Population Trends and Policies | Global Change Biology
Behavioural and cognitive sciences | Expanding Knowledge through Studies of Human Society | Social Structure and Health | Disease distribution and transmission | Disease Distribution and Transmission (incl. Surveillance and Response) |
Publisher: BMJ
Date: 22-01-2016
DOI: 10.1136/SEXTRANS-2015-052421
Abstract: HIV diagnoses among men who have sex with men (MSM) in several high-income countries, including Australia, have increased substantially over recent years. Australia, in line with global prevention strategies, has emphasised a 'test and treat' HIV prevention strategy which relies on timely detection of HIV through frequent testing by those at risk. We examined trends in repeat testing among MSM defined as 'high-risk' according to Australian testing guidelines. HIV test records from MSM attending high caseload clinics in Melbourne 2007-2013 and classified as high-risk were analysed. Binary outcomes of 'test within 3 months' and 'test within 6 months' were assigned to tests within in iduals' panel of records. Negative binomial regressions assessed trends in overall HIV testing and returning within 3 and 6 months. Annualised proportions of return tests (2007-2012) were compared using two-s le z tests. Across 18 538 tests among 7117 high-risk MSM attending primary care clinics in Melbourne (2007-2013), the number of annual HIV tests increased (p<0.01). Between 2007 and 2012 annualised proportions of tests with a subsequent test within 3 and 6 months also increased (p<0.01) however, by 2012 only 36.4% and 15.1% of tests were followed by another test inside 6 and 3 months, respectively. Repeat testing among high-risk MSM in Australia remains unacceptably low, with recent modest increases in testing unlikely to deliver meaningful prevention impact. Removing known barriers to HIV testing is needed to maximise the potential benefit of test and treat-based HIV prevention.
Publisher: Springer Science and Business Media LLC
Date: 22-11-2019
DOI: 10.1186/S12916-019-1452-0
Abstract: Tuberculosis (TB) control efforts are h ered by an imperfect understanding of TB epidemiology. The true age distribution of disease is unknown because a large proportion of in iduals with active TB remain undetected. Understanding of transmission is limited by the asymptomatic nature of latent infection and the pathogen’s capacity for late reactivation. A better understanding of TB epidemiology is critically needed to ensure effective use of existing and future control tools. We use an agent-based model to simulate TB epidemiology in the five highest TB burden countries—India, Indonesia, China, the Philippines and Pakistan—providing unique insights into patterns of transmission and disease. Our model replicates demographically realistic populations, explicitly capturing social contacts between in iduals based on local estimates of age-specific contact in household, school and workplace settings. Time-varying programmatic parameters are incorporated to account for the local history of TB control. We estimate that the 15–19-year-old age group is involved in more than 20% of transmission events in India, Indonesia, the Philippines and Pakistan, despite representing only 5% of the local TB incidence. According to our model, childhood TB represents around one fifth of the incident TB cases in these four countries. In China, three quarters of incident TB were estimated to occur in the ≥ 45-year-old population. The calibrated per-contact transmission risk was found to be similar in each of the five countries despite their very different TB burdens. Adolescents and young adults are a major driver of TB in high-incidence settings. Relying only on the observed distribution of disease to understand the age profile of transmission is potentially misleading.
Publisher: Elsevier BV
Date: 03-2020
DOI: 10.1016/J.EPIDEM.2019.100374
Abstract: TB mathematical models employ various assumptions and approaches in dealing with the heterogeneous infectiousness of persons with active TB. We reviewed existing approaches and considered the relationship between them and existing epidemiological evidence. We searched the following electronic bibliographic databases from inception to 9 October 2018: MEDLINE, EMBASE, Biosis, Global Health and Scopus. Two investigators extracted data using a standardised data extraction tool. We included in the review any transmission dynamic model of M. tuberculosis transmission explicitly simulating heterogeneous infectiousness of person with active TB. We extracted information including: study objective, model structure, number of active TB compartments, factors used to stratify the active TB compartment, relative infectiousness of each active TB compartment and any intervention evaluated in the model. Our search returned 1899 unique references, of which the full text of 454 records were assessed for eligibility, and 99 studies met the inclusion criteria. Of these, 89 used compartmental models implemented with ordinary differential equations, while the most common approach to stratification of the active TB compartment was to incorporate two levels of infectiousness. However, various clinical characteristics were used to stratify the active TB compartments, and models differed as to whether they permitted transition between these states. Thirty-four models stratified the infectious compartment according to sputum smear status or pulmonary involvement, while 18 models stratified based on health care-related factors. Variation in infectiousness associated with drug-resistant M. tuberculosis was the rationale for stratifying active TB in 33 models, with these models consistently assuming that drug-resistant active TB cases were less infectious. Given the evidence of extensive heterogeneity in infectiousness of in iduals with active TB, an argument exists for incorporating heterogeneous infectiousness, although this should be considered in light of the objectives of the study and the research question. PROSPERO Registration: CRD42019111936.
Publisher: Elsevier BV
Date: 05-2021
Publisher: Elsevier BV
Date: 10-2014
DOI: 10.1016/J.JTBI.2014.05.023
Abstract: We present a mathematical model to simulate tuberculosis (TB) transmission in highly endemic regions of the Asia-Pacific, where epidemiology does not appear to be primarily driven by HIV-coinfection. The ten-compartment deterministic model captures many of the observed phenomena important to disease dynamics, including partial and temporary vaccine efficacy, declining risk of active disease following infection, the possibility of reinfection both during the infection latent period and after treatment, multidrug resistant TB (MDR-TB) and de novo resistance during treatment. We found that the model could not be calibrated to the estimated incidence rate without allowing for reinfection during latency, and that even in the presence of a moderate fitness cost and a lower value of R0, MDR-TB becomes the dominant strain at equilibrium. Of the modifiable programmatic parameters, the rate of detection and treatment commencement was the most important determinant of disease rates with each respective strain, while vaccination rates were less important. Improved treatment of drug-susceptible TB did not result in decreased rates of MDR-TB through prevention of de novo resistance, but rather resulted in a modest increase in MDR-TB through strain replacement. This was due to the considerably greater relative contribution of community transmission to MDR-TB incidence, by comparison to de novo lification of resistance in previously susceptible strains.
Publisher: Springer Science and Business Media LLC
Date: 07-10-2019
DOI: 10.1038/S41370-019-0176-8
Abstract: Pneumonia accounts for 1.5% of all overnight hospital admission in Australia. We investigated the nonlinear and delay effect of weather (temperature and rainfall) on pneumonia. This study was based on a large cohort of inpatients that were hospitalized due to pneumonia between 2006 and 2016. Cases were identified using the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, Australian Modification (ICD10-AM) codes J10.0*-J18.0*. A time-varying distributed lag nonlinear model was used to estimate the burden of the disease attributable to varying weather-lag pneumonia relationships and identify vulnerable groups. The relative risk (presented as logRR) associated with temperature was immediate and highest in late winter at the lowest temperature of 16 °C (logRR = 1.13, 95% confidence intervals (CI): 0.59, 1.66). The cumulative effect over the lag range 0-8 weeks revealed two peaks for low (12 mm, logRR = 0.73, 95% CI: 0.32, 1.13) and moderately high rainfall (51 mm) with logRR of 1.15 (95% CI: 0.10, 2.20). A substantial number, 22.50% (95% empirical CI: 1.83, 34.68), of pneumonia cases were attributable to temperature (mostly due to moderate low temperatures). Females and indigenous (Aboriginal and Torres Strait Islander) patients were particularly vulnerable to the impact of temperature-related pneumonia. In this study, we highlighted the delayed effects and magnitude of burden of pneumonia that is associated with low temperature and rainfall. The findings in this study can inform a better understanding of the health implications and burden associated with pneumonia to support discussion-making in healthcare and establish a strategy for prevention and control of the disease among vulnerable groups.
Publisher: Cambridge University Press (CUP)
Date: 02-2009
DOI: 10.1086/593967
Abstract: Increasing length of hospital stay is associated with methicillin-resistant Staphylococcus aureus (MRSA) acquisition. The exact risk of becoming colonized with MRSA on a given day has not been clearly elucidated. We determined the hazard of MRSA acquisition in relation to the length of time spent in an intensive care unit in which only standard precautions were used for MRSA-colonized and MRSA-infected patients. This study took place at a tertiary referral hospital intensive care unit in which patients were screened for MRSA at hospital admission, at hospital discharge, and twice weekly during intensive care unit stay. We analyzed the hazard of MRSA acquisition by using a statistical smoothing kernel for hazard with a width of 5 days. Patients were stratified according to age, sex, medical unit, and length of hospital stay. Of the patients who were at risk of colonization or infection, 12.8% acquired MRSA. The mean length of stay in the intensive care unit was 7.2 days. The daily hazard of acquiring MRSA was less than 1% at admission to the intensive care unit and increased linearly to more than 2% risk per day by day 12, followed by a leveling out of risk. The daily hazard of acquiring MRSA is not constant. This has implications for studies that assume a constant hazard in their analysis and should be considered.
Publisher: Springer Science and Business Media LLC
Date: 09-02-2019
DOI: 10.1007/S00285-018-01324-1
Abstract: We investigate the global dynamics of a general Kermack-McKendrick-type epidemic model formulated in terms of a system of renewal equations. Specifically, we consider a renewal model for which both the force of infection and the infected removal rates are arbitrary functions of the infection age, [Formula: see text], and use the direct Lyapunov method to establish the global asymptotic stability of the equilibrium solutions. In particular, we show that the basic reproduction number, [Formula: see text], represents a sharp threshold parameter such that for [Formula: see text], the infection-free equilibrium is globally asymptotically stable whereas the endemic equilibrium becomes globally asymptotically stable when [Formula: see text], i.e. when it exists.
Publisher: Hindawi Limited
Date: 2010
DOI: 10.1155/2010/284028
Abstract: Aim : To survey practices in the diagnosis and management of latent tuberculosis infection (LTBI) in Australia and New Zealand. Methods : Infectious diseases and respiratory physicians and trainees were invited to complete an online questionnaire concerning various aspects of LTBI management. Results : The questionnaire was completed by 126 clinicians self-reporting regular management of LTBI. Respondents were experienced physicians, with 95/126 (75.4%) having managed LTBI for more than 5 years. Forty-seven (37.3%) reported seeing more than 5 patients per month for assessment of LTBI. Substantial variation among clinicians was reported in relation to a number of common clinical scenarios. For instance, while 52/126 (43.7%) informed patients that the incidence of severe hepatotoxicity related to isoniazid monotherapy was 0.1–0.5%, 21/126 (15.7%) thought it was 5%. 36/126 (28.6%) clinicians would proceed with TNF- a therapy following an indeterminate screening: interferon- ? assay, while 78/126 (61.9%) would perform further investigations and 12/126 (9.5%) would initiate isoniazid therapy. Follow-up intervals during therapy varied from 1–3 monthly, with liver function testing performed routinely by 89/126 (70.6%). Conclusion : This study demonstrated a large degree of variation in clinical practice of LTBI management in Australia and New Zealand. Strategies for increasing uniformity of practice are required, including improved guidelines and physician education.
Publisher: Wiley
Date: 25-03-2019
DOI: 10.1111/APT.15210
Abstract: Global targets to eliminate hepatitis C (HCV) might be met by sustained treatment uptake. To describe factors facilitating HCV treatment uptake and potential challenges to sustaining treatment levels after universal access to direct-acting anti-virals (DAA) across Australia. We analysed national Pharmaceutical Benefits Scheme data to determine the number of DAA prescriptions commenced before and after universal access from March 2016 to June 2017. We inferred facilitators and barriers to treatment uptake, and challenges that will prevent local and global jurisdictions reaching elimination targets. In 2016, 32 877 in iduals (14% of people living with HCV in Australia) commenced HCV DAA treatment, and 34 952 (15%) in iduals commenced treatment in the first year of universal access. Treatment uptake peaked at 13 109 DAA commencements per quarter immediately after universal access, but more than halved (to 5320 in 2017 Q2) within 12 months. General practitioners have written 24% of all prescriptions but with a significantly increased proportion over time (9% in 2016 Q1 to 37% in 2017 Q2). In contrast, hepatology or infectious diseases specialists have written a declining share from 74% to 38% during the same period. General practitioners provided a greater proportion (47%) of care in regional/remote areas than major cities. Broad treatment access led to rapid initial increases in treatment uptake, but this uptake has not been sustained. Our results suggest achieving global elimination targets requires more than treatment availability: people with HCV need easy access to testing and linkage to care in community settings employing a erse prescriber base.
Publisher: Public Library of Science (PLoS)
Date: 06-2010
Publisher: Springer Science and Business Media LLC
Date: 28-05-2019
Publisher: Oxford University Press (OUP)
Date: 05-10-2019
DOI: 10.1093/JAC/DKY403
Abstract: Latent tuberculosis infection (LTBI) is a critical driver of the global burden of active TB, and therefore LTBI treatment is key for TB elimination. Treatment regimens for LTBI include self-administered daily isoniazid for 6 (6H) or 9 (9H) months, self-administered daily rif icin plus isoniazid for 3 months (3RH), self-administered daily rif icin for 4 months (4R) and weekly rifapentine plus isoniazid for 3 months self-administered (3HP-SAT) or administered by a healthcare worker as directly observed therapy (3HP-DOT). Data on the relative cost-effectiveness of these regimens are needed to assist policymakers and clinicians in selecting an LTBI regimen. To evaluate the cost-effectiveness of all regimens for treating LTBI. We developed a Markov model to investigate the cost-effectiveness of 3HP-DOT, 3HP-SAT, 4R, 3RH, 9H and 6H for LTBI treatment in a cohort of 10000 adults with LTBI. Cost-effectiveness was evaluated from a health system perspective over a 20 year time horizon. Compared with no preventive treatment, 3HP-DOT, 3HP-SAT, 4R, 3RH, 9H and 6H prevented 496, 470, 442, 418, 370 and 276 additional cases of active TB per 10000 patients, respectively. All regimens reduced costs and increased QALYs compared with no preventive treatment. 3HP was more cost-effective under DOT than under SAT at a cost of US$27948 per QALY gained. Three months of weekly rifapentine plus isoniazid is more cost-effective than other regimens. Greater recognition of the benefits of short-course regimens can contribute to the scale-up of prevention and achieving the 'End TB' targets.
Publisher: AMPCo
Date: 06-2012
DOI: 10.5694/MJA12.10684
Publisher: Springer Science and Business Media LLC
Date: 06-08-2010
DOI: 10.1007/S00134-010-2019-X
Abstract: To determine whether any of several quality improvement interventions with none specifically targeting methicillin-resistant Staphylococcus aureus (MRSA) were associated with a decline in endemic MRSA prevalence in an intensive care unit (ICU) where active screening and contact isolation precautions for known MRSA colonised patients are not practised. Medical-surgical ICU with 2,000 admissions/year. 8.5-year retrospective time-series analysis. ICU re-location, antibiotic stewardship utilising computerised decision-support and infectious-diseases physician rounds, dedicated ICU infection control practitioners, alcohol-based hand rub solution (ABHRS). Regression modelling was used to evaluate trends in S. aureus prevalence density (monthly clinical isolates per 1,000 patient-days), antibiotic consumption, infection control consumables, ABHRS and their temporal relationship with MRSA prevalence. Methicillin-resistant S. aureus prevalence density decreased by 83% [95% confidence interval (CI) -68% to -91%, p < 0.001]. Rates of MRSA bacteraemia decreased 89% (95% CI -79% to -94%, p = 0.001) with no statistically significant change in methicillin-sensitive S. aureus bacteraemia. Hospital MRSA prevalence density decreased 17% (95% CI -5% to -27%, p = 0.005), suggesting that ICU was not shifting MRSA elsewhere. In ICU, broad-spectrum antibiotic use decreased by 26% (95% CI -12% to -38%, p = 0.008), coinciding with a decrease in MRSA, but time-series analysis did not show a significant association. On multivariate analysis, only ABHRS was significantly associated with a decrease in MRSA, but it was formally introduced late in the study period when MRSA was already in decline. General quality improvement measures were associated with a decrease in endemic MRSA in a high-risk setting without use of resource-intensive active surveillance and isolation practices.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 06-2012
Publisher: American Society for Microbiology
Date: 10-2009
DOI: 10.1128/AAC.01301-08
Abstract: Melioidosis is an infectious disease with a propensity for relapse, despite prolonged antibiotic eradication therapy for 12 to 20 weeks. A pharmacokinetic (PK) simulation study was performed to determine the optimal dosing of cotrimoxazole (trimethoprim-sulfamethoxazole [TMP-SMX]) used in current eradication regimens in Thailand and Australia. Data for bioavailability, protein binding, and coefficients of absorption and elimination were taken from published literature. Apparent volumes of distribution were correlated with body mass and were estimated separately for Thai and Australian populations. In vitro experiments demonstrated concentration-dependent killing. In Australia, the currently used eradication regimen (320 [TMP]/1,600 [SMX] mg every 12 h [q12h]) was predicted to achieve the PK-pharmacodynamic (PD) target (an area under the concentration-time curve from 0 to 24 h/MIC ratio of for both TMP and SMX) for strains with the MIC 90 of Australian strains (≤1/19 mg/liter). In Thailand, the former regimen of 160/800 mg q12h would not be expected to attain the target for strains with an MIC of ≥1/19 mg/liter, but the recently implemented weight-based regimen ( kg [body weight], 160/800 mg q12h 40 to 60 kg, 240/1,200 mg q12h kg, 320/1,600 mg q12h) would be expected to achieve adequate concentrations for strains with an MIC of ≤1/19 mg/liter. The results were sensitive to the variance of the PK parameters. Prospective PK-PD studies of Asian populations are needed to optimize TMP-SMX dosing in melioidosis.
Publisher: eLife Sciences Publications, Ltd
Date: 13-08-2020
DOI: 10.7554/ELIFE.58785
Abstract: As of 1 May 2020, there had been 6808 confirmed cases of COVID-19 in Australia. Of these, 98 had died from the disease. The epidemic had been in decline since mid-March, with 308 cases confirmed nationally since 14 April. This suggests that the collective actions of the Australian public and government authorities in response to COVID-19 were sufficiently early and assiduous to avert a public health crisis – for now. Analysing factors that contribute to in idual country experiences of COVID-19, such as the intensity and timing of public health interventions, will assist in the next stage of response planning globally. We describe how the epidemic and public health response unfolded in Australia up to 13 April. We estimate that the effective reproduction number was likely below one in each Australian state since mid-March and forecast that clinical demand would remain below capacity thresholds over the forecast period (from mid-to-late April).
Publisher: Oxford University Press (OUP)
Date: 15-05-2006
DOI: 10.1086/503439
Publisher: Elsevier BV
Date: 2019
Publisher: American Medical Association (AMA)
Date: 27-10-2008
DOI: 10.1001/ARCHINTE.168.19.2095
Abstract: Elderly patients are emerging as a population at high risk for infective endocarditis (IE). However, adequately sized prospective studies on the features of IE in elderly patients are lacking. In this multinational, prospective, observational cohort study within the International Collaboration on Endocarditis, 2759 consecutive patients were enrolled from June 15, 2000, to December 1, 2005 1056 patients with IE 65 years or older were compared with 1703 patients younger than 65 years. Risk factors, predisposing conditions, origin, clinical features, course, and outcome of IE were comprehensively analyzed. Elderly patients reported more frequently a hospitalization or an invasive procedure before IE onset. Diabetes mellitus and genitourinary and gastrointestinal cancer were the major predisposing conditions. Blood culture yield was higher among elderly patients with IE. The leading causative organism was Staphylococcus aureus, with a higher rate of methicillin resistance. Streptococcus bovis and enterococci were also significantly more prevalent. The clinical presentation of elderly patients with IE was remarkable for lower rates of embolism, immune-mediated phenomena, or septic complications. At both echocardiography and surgery, fewer vegetations and more abscesses were found, and the gain in the diagnostic yield of transesophageal echocardiography was significantly larger. Significantly fewer elderly patients underwent cardiac surgery (38.9% vs 53.5% P < .001). Elderly patients with IE showed a higher rate of in-hospital death (24.9% vs 12.8% P < .001), and age older than 65 years was an independent predictor of mortality. In this large prospective study, increasing age emerges as a major determinant of the clinical characteristics of IE. Lower rates of surgical treatment and high mortality are the most prominent features of elderly patients with IE. Efforts should be made to prevent health care-associated acquisition and improve outcomes in this major subgroup of patients with IE.
Publisher: Oxford University Press (OUP)
Date: 19-08-2010
DOI: 10.1111/J.1365-2249.2010.04221.X
Abstract: It has been proposed that mannose-binding lectin (MBL) levels may impact upon host susceptibility to tuberculosis (TB) infection however, evidence to date has been conflicting. We performed a literature review and meta-analysis of 17 human trials considering the effect of MBL2 genotype and/or MBL levels and TB infection. No significant association was demonstrated between MBL2 genotype and pulmonary TB infection. However, the majority of studies did not report MBL2 haplotype inclusive of promoter polymorphisms. Serum MBL levels were shown to be consistently elevated in the setting of TB infection. While this may indicate that high MBL levels protect against infection with TB, the increase was also of a degree consistent with the acute-phase reaction. This analysis suggests that the relatively poorly characterized MBL2 genotypes reported are not associated significantly with susceptibility to pulmonary TB infection, but high MBL serum levels may be.
Publisher: MDPI AG
Date: 19-09-2022
DOI: 10.3390/TROPICALMED7090251
Abstract: The international border between Australia and Papua New Guinea (PNG) serves as a gateway for the delivery of primary and tertiary healthcare for PNG patients presenting to Australian health facilities with presumptive tuberculosis (TB). An audit of all PNG nationals with presumptive TB who presented to clinics in the Torres Strait between 2016 and 2019 was conducted to evaluate outcomes for PNG patients and to consider the consistency and equity of decision-making regarding aeromedical evacuation. We also reviewed the current aeromedical retrieval policy and the outcomes of patients referred back to Daru General Hospital in PNG. During the study period, 213 PNG nationals presented with presumptive TB to primary health centres (PHC) in the Torres Strait. In total, 44 (21%) patients were medically evacuated to Australian hospitals 26 met the evacuation criteria of whom 3 died, and 18 did not meet the criteria of whom 1 died. A further 22 patients who met the medical evacuation criteria into Australia were referred to Daru General Hospital of whom 2 died and 10 were lost to follow-up. The cross-border movement of people from PNG into Australia is associated with an emergent duty of care. Ongoing monitoring and evaluation of patient outcomes are necessary for transparency and justice.
Publisher: Elsevier BV
Date: 06-2021
Publisher: Springer Science and Business Media LLC
Date: 20-02-2014
Publisher: Springer Science and Business Media LLC
Date: 25-10-2007
DOI: 10.1007/S10096-007-0406-1
Abstract: Leptotrichia species typically colonize the oral cavity and genitourinary tract. We report the first two cases of endocarditis secondary to L. goodfellowii sp. nov. Both cases were identified using 16S rRNA gene sequencing. Review of the English literature revealed only two other cases of Leptotrichia sp. endocarditis.
Publisher: Elsevier BV
Date: 08-2017
DOI: 10.1016/J.JINF.2017.04.011
Abstract: A biomarker indicating successful tuberculosis (TB) therapy would assist in determining appropriate length of treatment. This study aimed to determine changes in mycobacteria-specific antigen-induced cytokine biomarkers in patients receiving therapy for latent or active TB, to identify biomarkers potentially correlating with treatment success. A total of 33 adults with active TB and 36 with latent TB were followed longitudinally over therapy. Whole blood stimulation assays using mycobacteria-specific antigens (CFP-10, ESAT-6, PPD) were done on s les obtained at 0, 1, 3, 6 and 9 months. Cytokine responses (IFN-γ, IL-1ra, IL-2, IL-10, IL-13, IP-10, MIP-1β, and TNF-α) in supernatants were measured by Luminex xMAP immunoassay. In active TB cases, median IL-1ra (with CFP-10 and with PPD stimulation), IP-10 (CFP-10, ESAT-6), MIP-1β (ESAT-6, PPD), and TNF-α (ESAT-6) responses declined significantly over the course of therapy. In latent TB cases, median IL-1ra (CFP-10, ESAT-6, PPD), IL-2 (CFP-10, ESAT-6), and IP-10 (CFP-10, ESAT-6) responses declined significantly. Mycobacteria-specific cytokine responses change significantly over the course of therapy, and their kinetics in active TB differ from those observed in latent TB. In particular, mycobacteria-specific IL-1ra responses are potential correlates of successful therapy in both active and latent TB.
Publisher: Elsevier BV
Date: 12-2015
DOI: 10.1016/J.EPIDEM.2015.08.002
Abstract: The demographic structure of populations in both more developed and less developed countries is changing: increases in life expectancy and declining fertility have led to older populations and smaller households. The implications of these demographic changes for the spread and control of infectious diseases are not fully understood. Here we use an in idual based model with realistic and dynamic age and household structure to demonstrate the marked effect that demographic change has on disease transmission at the population and household level. The decline in fertility is associated with a decrease in disease incidence and an increase in the age of first infection, even in the absence of vaccination or other control measures. Although large households become rarer as fertility decreases, we show that there is a proportionate increase in incidence of disease in these households as the accumulation of susceptible clusters increases the potential for explosive outbreaks. By modelling vaccination, we provide a direct comparison of the relative importance of demographic change and vaccination on incidence of disease. We highlight the increased risks associated with unvaccinated households in a low fertility setting if vaccine behaviour is correlated with household membership. We suggest that models that do not account for future demographic change, and especially its effect on household structure, may potentially overestimate the impact of vaccination.
Publisher: Springer Science and Business Media LLC
Date: 18-10-2018
Publisher: Wiley
Date: 21-12-2011
Publisher: Oxford University Press (OUP)
Date: 21-05-2021
DOI: 10.1093/AJE/KWAB150
Abstract: Many tuberculosis (TB) cases in low-incidence settings are attributed to reactivation of latent TB infection (LTBI) acquired overseas. We assessed the cost-effectiveness of community-based LTBI screening and treatment strategies in recent migrants to a low-incidence setting (Australia). A decision-analytical Markov model was developed that cycled 1 migrant cohort (≥11-year-olds) annually over a lifetime from 2020. Postmigration/onshore and offshore (screening during visa application) strategies were compared with existing policy (chest x-ray during visa application). Outcomes included TB cases averted and discounted cost per quality-adjusted life-year (QALY) gained from a health-sector perspective. Most recent migrants are young adults and cost-effectiveness is limited by their relatively low LTBI prevalence, low TB mortality risks, and high emigration probability. Onshore strategies cost at least $203,188 (Australian) per QALY gained, preventing approximately 2.3%–7.0% of TB cases in the cohort. Offshore strategies (screening costs incurred by migrants) cost at least $13,907 per QALY gained, preventing 5.5%–16.9% of cases. Findings were most sensitive to the LTBI treatment quality-of-life decrement (further to severe adverse events) with a minimal decrement, all strategies caused more ill health than they prevented. Additional LTBI strategies in recent migrants could only marginally contribute to TB elimination and are unlikely to be cost-effective unless screening costs are borne by migrants and potential LTBI treatment quality-of-life decrements are ignored.
Publisher: The Royal Society
Date: 09-2018
DOI: 10.1098/RSOS.180887
Abstract: Geospatial tuberculosis (TB) hotspots are hubs of TB transmission both within and across community groups. We aimed to quantify the extent to which these hotspots account for the spatial spread of TB in a high-burden setting. We developed spatially coupled models to quantify the spread of TB from geographical hotspots to distant regions in rural Ethiopia. The population was ided into three ‘patches’ based on their proximity to transmission hotspots, namely hotspots, adjacent regions and remote regions. The models were fitted to 5-year notification data aggregated by the metapopulation structure. Model fitting was achieved with a Metropolis–Hastings algorithm using a Poisson likelihood to compare model-estimated notification rate with observed notification rates. A cross-coupled metapopulation model with assortative mixing by region closely fit to notification data as assessed by the deviance information criterion. We estimated 45 hotspot-to-adjacent regions transmission events and 2 hotspot-to-remote regions transmission events occurred for every 1000 hotspot-to-hotspot transmission events. Although the degree of spatial coupling was weak, the proportion of infections in the adjacent region that resulted from mixing with hotspots was high due to the high prevalence of TB cases in a hotspot region, with approximately 75% of infections attributable to hotspot contact. Our results suggest that the role of hotspots in the geospatial spread of TB in rural Ethiopia is limited, implying that TB transmission is primarily locally driven.
Publisher: Proceedings of the National Academy of Sciences
Date: 02-11-2022
Abstract: Community-associated, methicillin-resistant Staphylococcus aureus (MRSA) lineages have emerged in many geographically distinct regions around the world during the past 30 y. Here, we apply consistent phylodynamic methods across multiple community-associated MRSA lineages to describe and contrast their patterns of emergence and dissemination. We generated whole-genome sequencing data for the Australian sequence type (ST) ST93-MRSA-IV from remote communities in Far North Queensland and Papua New Guinea, and the Bengal Bay ST772-MRSA-V clone from metropolitan communities in Pakistan. Increases in the effective reproduction number (R e ) and sustained transmission (R e 1) coincided with spread of progenitor methicillin-susceptible S. aureus (MSSA) in remote northern Australian populations, dissemination of the ST93-MRSA-IV genotype into population centers on the Australian East Coast, and subsequent importation into the highlands of Papua New Guinea and Far North Queensland. Applying the same phylodynamic methods to existing lineage datasets, we identified common signatures of epidemic growth in the emergence and epidemiological trajectory of community-associated S. aureus lineages from America, Asia, Australasia, and Europe. Surges in R e were observed at the ergence of antibiotic-resistant strains, coinciding with their establishment in regional population centers. Epidemic growth was also observed among drug-resistant MSSA clades in Africa and northern Australia. Our data suggest that the emergence of community-associated MRSA in the late 20th century was driven by a combination of antibiotic-resistant genotypes and host epidemiology, leading to abrupt changes in lineage-wide transmission dynamics and sustained transmission in regional population centers.
Publisher: Elsevier BV
Date: 04-2007
DOI: 10.1016/J.JTBI.2006.11.008
Abstract: To estimate the transmission rate of MRSA in an intensive care unit (ICU) in an 800 bed Australian teaching hospital and predict the impact of infection control interventions. A mathematical model was developed which consisted of four compartments: colonised and uncolonised patients and contaminated and uncontaminated health-care workers (HCWs). Patient movements, MRSA acquisition and daily prevalence data were collected from an ICU over 939 days. Hand hygiene compliance and the probability of MRSA transmission from patient to HCW per discordant contact were measured during the study. Attack rate and reproduction ratio were estimated using Bayesian methods. The impact of a number of interventions on attack rate was estimated using both stochastic and deterministic versions of the model. The mean number of secondary cases arising from the ICU admission of colonised patients, also called the ward reproduction ratio, R(w), was estimated to be 0.50 (95% CI 0.39-0.62). The attack rate was one MRSA transmission per 160 (95% CI 130-210) uncolonised-patient days. Results were not sensitive to uncertainty in measured model parameters (hand hygiene rate and transmission probability per contact). Hand hygiene was predicted to be the most effective intervention. Decolonisation was predicted to be relatively ineffective. Increasing HCW numbers was predicted to increase MRSA transmission, in the absence of patient cohorting. The predictions of the stochastic model differed from those of the deterministic model, with lower levels of colonisation predicted by the stochastic model. The number of secondary cases of MRSA colonisation within the ICU in this study was below unity. Transmission of MRSA was sustained through admission of colonised patients. Stochastic model simulations give more realistic predictions in hospital ward settings than deterministic models. Increasing staff does not necessarily lead to reduced transmission of nosocomial pathogens.
Publisher: Springer Science and Business Media LLC
Date: 15-09-2009
DOI: 10.1007/S00134-009-1619-9
Abstract: To assess the generalisability of published clinical risk predictive models for invasive candidiasis in ICU patients. The performance characteristics of published clinical risk factor-only and Candida colonisation-only predictive models for invasive candidiasis were assessed in a multicentre cohort of Australian ICU patients. Clinical risk factors and Candida colonisation parameters were collected prospectively from patients. The two clinical risk factor-only predictive models applied to an Australian patient cohort (n = 615) performed less well than in published studies involving derivation populations. Model performance characteristics improved when Candida colonisation parameters were added post-hoc. Risk predictive models should factor in both clinical risk factors and Candida colonisation parameters. Integrating these models into therapeutic algorithms first requires external validation in different patient populations and settings.
Publisher: Public Library of Science (PLoS)
Date: 14-12-2015
Publisher: Cold Spring Harbor Laboratory
Date: 19-05-2020
DOI: 10.1101/2020.05.12.20099036
Abstract: Australia is one of a few countries which has managed to control COVID-19 epidemic before a major epidemic took place. Currently with just under 7000 cases and 100 deaths, Australia is seeing less than 20 new cases per day. This is a positive outcome, but makes estimation of current effective reproduction numbers difficult to estimate. Australia, like much of the world is poised to step out of lockdown and looking at which measures to relax first. We use age-based contact matrices, calibrated to Chinese data on reproduction numbers and difference in infectiousness and susceptibility of children to generate next generation matrices (NGMs) for Australia. These matrices have a spectral radius of 2.49, which is hence our estimated basic reproduction number for Australia. The effective reproduction number (Reff) for Australia during the April/May lockdown period is estimated by other means to be around 0.8. We simulate the impact of lockdown on the NGM by first applying observations through Google Mobility Report for Australia at 3 locations: home (increased contacts by 18%), work (reduced contacts by 34%) and other (reduced contacts by 40%), and we reduce schools to 3% reflecting attendance rates during lockdown. Applying macro-distancing to the NGM leads to a spectral radius of 1.76. We estimate that the further reduction of the reproduction number to current levels of Reff = 0.8 is achieved by a micro-distancing factor of 0.26. That is, in a given location, people are 26% as likely as usual to have an effective contact with another person. We apply both macro and micro-distancing to the NGMs to examine the impact of different exit strategies. We find that reopening schools is estimated to reduce Reff from 0.8 to 0.78. This is because increase in school contact is offset by decrease in home contact. The NGMs all estimate that adults aged 30-50 are responsible for the majority of transmission. We also find that micro-distancing is critically important to maintain Reff . There is considerable uncertainty in these estimates and a sensitivity and uncertainty analysis is presented.
Publisher: Public Library of Science (PLoS)
Date: 30-09-2014
Publisher: American Medical Association (AMA)
Date: 09-03-2009
Publisher: Informa UK Limited
Date: 25-09-2015
Publisher: American Association for the Advancement of Science (AAAS)
Date: 28-08-2009
Publisher: BMJ
Date: 12-04-2016
DOI: 10.1136/GUTJNL-2016-311504
Abstract: The WHO's draft HCV elimination targets propose an 80% reduction in incidence and a 65% reduction in HCV-related deaths by 2030. We estimate the treatment scale-up required and cost-effectiveness of reaching these targets among injecting drug use (IDU)-acquired infections using Australian disease estimates. A mathematical model of HCV transmission, liver disease progression and treatment among current and former people who inject drugs (PWID). Treatment scale-up and the most efficient allocation to priority groups (PWID or patients with advanced liver disease) were determined total healthcare and treatment costs, quality-adjusted life years (QALYs) and incremental cost-effectiveness ratios (ICERs) compared with inaction were calculated. 5662 (95% CI 5202 to 6901) courses per year (30/1000 IDU-acquired infections) were required, prioritised to patients with advanced liver disease, to reach the mortality target. 4725 (3278-8420) courses per year (59/1000 PWID) were required, prioritised to PWID, to reach the incidence target this also achieved the mortality target, but to avoid clinically unacceptable HCV-related deaths an additional 5564 (1959-6917) treatments per year (30/1000 IDU-acquired infections) were required for 5 years for patients with advanced liver disease. Achieving both targets in this way cost $A4.6 ($A4.2-$A4.9) billion more than inaction, but gained 184 000 (119 000-417 000) QALYs, giving an ICER of $A25 121 ($A11 062-$A39 036) per QALY gained. Achieving WHO elimination targets with treatment scale-up is likely to be cost-effective, based on Australian HCV burden and demographics. Reducing incidence should be a priority to achieve both WHO elimination goals in the long-term.
Publisher: Cold Spring Harbor Laboratory
Date: 02-04-2020
DOI: 10.1101/2020.03.30.20048009
Abstract: Around the world there are ex les of both effective control (e.g., South Korea, Japan) and less successful control (e.g., Italy, Spain, United States) of COVID-19 with dramatic differences in the consequent epidemic curves. Models agree that flattening the curve without controlling the epidemic completely is insufficient and will lead to an overwhelmed health service. A recent model, calibrated for the UK and US, demonstrated this starkly. We used a simple compartmental deterministic model of COVID-19 transmission in Australia, to illustrate the dynamics resulting from shifting or flattening the curve versus completely squashing it. We find that when the reproduction number is close to one, a small decrease in transmission leads to a large reduction in burden (i.e., cases, deaths and hospitalisations), but achieving this early in the epidemic through social distancing interventions also implies that the community will not reach herd immunity. Australia needs not just to shift and flatten the curve, but to squash it by getting the reproduction number below one. This will require Australia to achieve transmission rates at least two thirds lower than those seen in the most severely affected countries. COVID-19 has been diagnosed in over 4,000 Australians. Up until mid-March, most were from international travel, but now we are seeing a rise in locally acquired cases. This study uses a simple transmission dynamic model to demonstrate the difference between moderate changes to the reproduction number and forcing the reproduction number below one. Lowering local transmission is becoming important in reducing the transmission of COVID-19. To maintain control of the epidemic, the focus should be on those in the community who do not regard themselves as at risk.
Publisher: Public Library of Science (PLoS)
Date: 07-2015
Publisher: Elsevier BV
Date: 12-2021
Publisher: Elsevier BV
Date: 05-2020
Publisher: Elsevier BV
Date: 04-2019
Publisher: Public Library of Science (PLoS)
Date: 03-01-2020
Publisher: Wiley
Date: 21-12-2012
Publisher: Elsevier BV
Date: 10-2004
DOI: 10.1016/J.JHIN.2004.06.010
Abstract: Hand hygiene is critical in the healthcare setting and it is believed that methicillin-resistant Staphylococcus aureus (MRSA), for ex le, is transmitted from patient to patient largely via the hands of health professionals. A study has been carried out at a large teaching hospital to estimate how often the gloves of a healthcare worker are contaminated with MRSA after contact with a colonized patient. The effectiveness of handwashing procedures to decontaminate the health professionals' hands was also investigated, together with how well different healthcare professional groups complied with handwashing procedures. The study showed that about 17% (9-25%) of contacts between a healthcare worker and a MRSA-colonized patient results in transmission of MRSA from a patient to the gloves of a healthcare worker. Different health professional groups have different rates of compliance with infection control procedures. Non-contact staff (cleaners, food services) had the shortest handwashing times. In this study, glove use compliance rates were 75% or above in all healthcare worker groups except doctors whose compliance was only 27%.
Publisher: Informa UK Limited
Date: 10-2014
DOI: 10.2147/DHPS.S68837
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 11-2017
DOI: 10.1097/CCM.0000000000002654
Abstract: The primary objective was to conduct a meta-analysis on published observational cohort data describing the association between acetyl-salicylic acid (aspirin) use prior to the onset of sepsis and mortality in hospitalized patients. Studies that reported mortality in patients on aspirin with sepsis with a comparison group of patients with sepsis not on prior aspirin therapy were included. Fifteen studies described hospital-based cohorts ( n = 17,065), whereas one was a large insurance-based database ( n = 683,421). In idual-level patient data were incorporated from all selected studies. Propensity analyses with 1:1 propensity score matching at the study level were performed, using the most consistently available covariates judged to be associated with aspirin. Meta-analyses were performed to estimate the pooled average treatment effect of aspirin on sepsis-related mortality. Use of aspirin was associated with a 7% (95% CI, 2–12% p = 0.005) reduction in the risk of death as shown by meta-analysis with considerable statistical heterogeneity ( I 2 = 61.6%). These results are consistent with effects ranging from a 2% to 12% reduction in mortality risk in patients taking aspirin prior to sepsis onset. This association anticipates results of definitive studies of the use of low-dose aspirin as a strategy for reduction of deaths in patients with sepsis.
Publisher: Elsevier BV
Date: 02-2014
Abstract: The 2050 Millennium Development Goals (MDG) for tuberculosis (TB) aim for elimination of TB as a public health issue. We used a mathematical modelling approach to evaluate the feasibility of this target in a low-prevalence setting with immigration-related strategies directed at latent tuberculosis. We used a stochastic in idual-based model to simulate tuberculosis disease among immigrants to Victoria, Australia a representative low-transmission setting. A variety of screening and treatment approaches aimed at preventing reactivation of latent infection were applied to evaluate overall tuberculosis incidence reduction and rates of multidrug resistant disease. Without additional intervention, tuberculosis incidence was predicted to reach 34.5 cases/million by 2050. Strategies involving the introduction of an available screening/treatment combination reduced TB incidence to between 16.9-23.8 cases/million, and required screening of 136-427 new arrivals for each case of TB prevented. Limiting screening to higher incidence regions of origin was less effective but more efficient. Public health strategies targeting latent tuberculosis infection in immigrants may substantially reduce tuberculosis incidence in a low prevalence region. However, immigration-focused strategies cannot achieve the 2050 MDG and alternative or complementary approaches are required.
Publisher: MDPI AG
Date: 15-07-2021
DOI: 10.3390/HEALTHCARE9070901
Abstract: Background: In this study, we aimed to assess the risk factors associated with mortality due to an infectious disease over the short-, medium-, and long-term based on a data-linkage study for patients discharged from an infectious disease unit in North Queensland, Australia, between 2006 and 2011. Methods: Age-sex standardised mortality rates (SMR) for different subgroups were estimated, and the Kaplan-Meier method was used to estimate and compare the survival experience among different groups. Results: Overall, the mortality rate in the hospital cohort was higher than expected in comparison with the Queensland population (SMR: 15.3, 95%CI: 14.9–15.6). The long-term mortality risks were significantly higher for severe infectious diseases than non-infectious diseases for male sex, Indigenous, residential aged care and elderly in iduals. Conclusion: In general, male sex, Indigenous status, age and comorbidity were associated with an increased hazard for all-cause deaths.
Publisher: Elsevier BV
Date: 09-2021
Publisher: BMJ
Date: 2017
Publisher: Elsevier BV
Date: 02-2021
Publisher: Springer Science and Business Media LLC
Date: 20-10-2015
DOI: 10.1038/SREP15468
Abstract: Vaccine effect, as measured in clinical trials, may not accurately reflect population-level impact. Furthermore, little is known about how sensitive apparent or real vaccine impacts are to factors such as the risk of re-infection or the mechanism of protection. We present a dynamic compartmental model to simulate vaccination for endemic infections. Several measures of effectiveness are calculated to compare the real and apparent impact of vaccination and assess the effect of a range of infection and vaccine characteristics on these measures. Although broadly correlated, measures of real and apparent vaccine effectiveness can differ widely. Vaccine impact is markedly underestimated when primary infection provides partial natural immunity, when coverage is high and when post-vaccination infectiousness is reduced. Despite equivalent efficacy, ‘all or nothing’ vaccines are more effective than ‘leaky’ vaccines, particularly in settings with high risk of re-infection and transmissibility. Latent periods result in greater real impacts when risk of re-infection is high, but this effect diminishes if partial natural immunity is assumed. Assessments of population-level vaccine effects against endemic infections from clinical trials may be significantly biased and vaccine and infection characteristics should be considered when modelling outcomes of vaccination programs, as their impact may be dramatic.
Publisher: International Union Against Tuberculosis and Lung Disease
Date: 2017
Abstract: To describe the distribution of tuberculosis (TB) and its drivers in Sheka Zone, a geographically remote region of Ethiopia. We collected data on TB patients treated from 2010 to 2014 in the Sheka Zone. Predictors of TB incidence were determined using a multivariate generalised linear regression model. We found significant spatial autocorrelation of TB incidence by kebele (the smallest administrative geographical sub ision in Ethiopia) (Moran's I = 0.3, P < 0.001). The average TB incidence per kebele ranged from 0 to 453 per 100 000 population per year, and was significantly associated with average TB incidence across adjacent kebeles, TB incidence in the same kebele in the previous year and health facility availability. Each increment in TB incidence by 10/100 000/year in adjacent kebeles or in a previous year was associated with an increase in TB incidence of respectively 3.0 and 5.5/100 000/year. Availability of a health centre was associated with an increase in TB incidence of 84.3/100 000. TB incidence in rural Ethiopia is highly heterogeneous, showing significant spatial autocorrelation. Both local transmission and access to health care are likely contributors to this pattern. Identification of local hotspots may assist in developing and optimising effective prevention and control strategies.
Publisher: Springer Science and Business Media LLC
Date: 30-05-2017
Publisher: Oxford University Press (OUP)
Date: 11-2018
DOI: 10.1093/CID/CIY938
Publisher: International Union Against Tuberculosis and Lung Disease
Date: 10-2012
Abstract: The effectiveness of public health strategies following exposure to multidrug-resistant tuberculosis (MDR-TB) is not clear. To perform long-term follow-up of MDR-TB contacts and review in idual outcomes and management approaches. Retrospective review of MDR-TB contacts identified by the Victorian Department of Health from 1995 to 2010. Health records, including personal medical and pharmacy records and statewide clinical and laboratory TB databases, were searched to identify management strategies and in idual outcomes. A total of 570 contacts of 47 MDR-TB cases were identified, with a total follow-up period of 3093 person-years of observation (PYO) since exposure. Of 570 contacts, 49 (8.6%) were considered likely to have been infected with Mycobacterium tuberculosis from index cases, and 11/49 (22.5%) of these were prescribed preventive therapy tailored to isolate susceptibility. No MDR-TB cases occurred in those receiving preventive treatment, while two cases were observed in those not treated (incidence 2878/100 000 PYO during the first 2 years post exposure). The risk of MDR-TB transmission to close contacts in this low-prevalence setting highlights the potential for public health strategies involving preventive treatment.
Publisher: Springer Science and Business Media LLC
Date: 16-08-2017
Publisher: Elsevier BV
Date: 08-2020
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 24-10-2014
DOI: 10.1002/HEP.27403
Abstract: With the development of new highly efficacious direct-acting antiviral (DAA) treatments for hepatitis C virus (HCV), the concept of treatment as prevention is gaining credence. To date, the majority of mathematical models assume perfect mixing, with injectors having equal contact with all other injectors. This article explores how using a networks-based approach to treat people who inject drugs (PWID) with DAAs affects HCV prevalence. Using observational data, we parameterized an exponential random graph model containing 524 nodes. We simulated transmission of HCV through this network using a discrete time, stochastic transmission model. The effect of five treatment strategies on the prevalence of HCV was investigated two of these strategies were (1) treat randomly selected nodes and (2) "treat your friends," where an in idual is chosen at random for treatment and all their infected neighbors are treated. As treatment coverage increases, HCV prevalence at 10 years reduces for both the high- and low-efficacy treatment. Within each set of parameters, the treat your friends strategy performed better than the random strategy being most marked for higher-efficacy treatment. For ex le, over 10 years of treating 25 per 1,000 PWID, the prevalence drops from 50% to 40% for the random strategy and to 33% for the treat your friends strategy (6.5% difference 95% confidence interval: 5.1-8.1). Treat your friends is a feasible means of utilizing network strategies to improve treatment efficiency. In an era of highly efficacious and highly tolerable treatment, such an approach will benefit not just the in idual, but also the community more broadly by reducing the prevalence of HCV among PWID.
Publisher: Cambridge University Press (CUP)
Date: 06-2008
DOI: 10.1086/588203
Abstract: Determining sensitivity and specificity of a postoperative infection surveillance process is a difficult undertaking. Because postoperative infections are rare, vast numbers of negative results exist, and it is often not reasonable to assess them all. This study gives a methodological framework for estimating sensitivity and specificity by taking only a small s le of the number of patients who test negative and comparing their findings to the reference or “gold standard” rather than comparing the findings of all patients to the gold standard. It provides a formula for deriving confidence intervals for these estimates and a guide to minimum requirements for s ling results.
Publisher: Public Library of Science (PLoS)
Date: 23-07-2020
Publisher: Elsevier BV
Date: 06-2008
DOI: 10.1016/J.JHIN.2008.02.021
Abstract: Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) are terms usually associated with diagnostic testing. Although these concepts have been expanded from diagnostic assays to surveillance systems, these systems are not like diagnostic assays. In attempting to estimate the sensitivity and specificity of surveillance systems, situations may arise where only the PPV, NPV and prevalence are known. We aim to demonstrate the equivalence of two methods for calculating sensitivity and specificity from PPV, NPV and prevalence. The formulae for sensitivity and specificity are calculated from first principles and compared with the adjustment of a standard contingency table. We have illustrated this method using a review of a s le of surgical site infection cases following coronary artery bypass grafting. The derived prevalence from the s le is an estimate of the population prevalence and is the value that must be used in the formulae for sensitivity and specificity as functions of PPV, NPV and prevalence to obtain the same estimates as those obtained from the adjusted contingency table. The general proof of this principle is provided as an Appendix. The sensitivity and specificity of surveillance systems can be calculated by two equivalent methods when only PPV, NPV and prevalence are known.
Publisher: BMJ
Date: 02-2018
DOI: 10.1136/BMJOPEN-2017-019593
Abstract: The sequelae of multidrug-resistant tuberculosis (MDR-TB) are poorly understood and inconsistently reported. We will aim to assess the existing evidence for the clinical, psychological, social and economic sequelae of MDR-TB and to assess the health-related quality of life in patients with MDR-TB. We will perform a systematic review and meta-analysis of published studies reporting sequelae of MDR-TB. We will search PubMed, SCOPUS, ProQuest, Web of Science and PsychINFO databases up to 5 September 2017. MDR-TB sequelae will include any clinical, psychological, social and economic effects as well as health-related quality of life that occur after MDR-TB treatment or illness. Two researchers will screen the titles and abstracts of all citations identified in our search, extract data, and assess the scientific quality using standardised formats. Providing there is appropriate comparability in the studies, we will use a random-effects meta-analysis model to produce pooled estimates of MDR-TB sequelae from the included studies. We will stratify the analyses based on treatment regimen, comorbidities (such as HIV status and diabetes mellitus), previous TB treatment history and study setting. As this study will be based on published data, ethical approval is not required. The final report will be disseminated through publication in a peer-reviewed scientific journal and will also be presented at relevant conferences. CRD42017073182 .
Publisher: Elsevier BV
Date: 12-2022
Publisher: Oxford University Press (OUP)
Date: 07-08-2021
DOI: 10.1093/CID/CIAA602
Abstract: Tuberculosis (TB) natural history remains poorly characterized, and new investigations are impossible as it would be unethical to follow up TB patients without treatment. We considered the reports identified in a previous systematic review of studies from the prechemotherapy era, and extracted detailed data on mortality over time. We used a Bayesian framework to estimate the rates of TB-induced mortality and self-cure. A hierarchical model was employed to allow estimates to vary by cohort. Inference was performed separately for smear-positive TB (SP-TB) and smear-negative TB (SN-TB). We included 41 cohorts of SP-TB patients and 19 cohorts of pulmonary SN-TB patients in the analysis. The median estimates of the TB-specific mortality rates were 0.389 year−1 (95% credible interval [CrI], .335–.449) and 0.025 year−1 (95% CrI, .017–.035) for SP-TB and SN-TB patients, respectively. The estimates for self-recovery rates were 0.231 year−1 (95% CrI, .177–.288) and 0.130 year−1 (95% CrI, .073–.209) for SP-TB and SN-TB patients, respectively. These rates correspond to average durations of untreated TB of 1.57 years (95% CrI, 1.37–1.81) and 5.35 years (95% CrI, 3.42–8.23) for SP-TB and SN-TB, respectively, when assuming a non-TB-related mortality rate of 0.014 year−1 (ie, a 70-year life expectancy). TB-specific mortality rates are around 15 times higher for SP-TB than for SN-TB patients. This difference was underestimated dramatically in previous TB modeling studies, raising concerns about the accuracy of the associated predictions. Despite being less infectious, SN-TB may be responsible for equivalent numbers of secondary infections as SP-TB due to its much longer duration.
Publisher: Elsevier BV
Date: 03-2012
DOI: 10.1016/J.JTBI.2011.12.008
Abstract: Hepatitis C virus (HCV) is a blood-borne virus that disproportionately affects people who inject drugs (PWIDs). Based on extensive interview and blood test data from a longitudinal study in Melbourne, Australia, we describe an in idual-based transmission model for HCV spread amongst PWID. We use this model to simulate the transmission of HCV on an empirical social network of PWID. A feature of our model is that sources of infection can be both network neighbours and non-neighbours via "importing". Data-driven estimates of sharing frequency and rate of importing are provided. Compared to an appropriately calibrated fully connected network, the empirical network provides some protective effect on the time to primary infection. We also illustrate heterogeneities in incidence rate of infection, both across and within node degrees (i.e., number of network partners). We explore the reduced risk of infection from spontaneously clearing cutpoint nodes whose infection status oscillates, both in theory and in simulation. Further, we show our model-based estimate of per-event transmission probability largely agrees with previous estimates at the lower end of the range 1-3% commonly cited.
Publisher: Center for Open Science
Date: 24-10-2023
Publisher: Oxford University Press (OUP)
Date: 19-05-2016
DOI: 10.1093/AJE/KWV323
Abstract: Tuberculosis (TB) and multidrug-resistant TB (MDR-TB) are major health problems in Western Province, Papua New Guinea. While comprehensive expansion of TB control programs is desirable, logistical challenges are considerable, and there is substantial uncertainty regarding the true disease burden. We parameterized our previously described mathematical model of Mycobacterium tuberculosis dynamics in Western Province, following an epidemiologic assessment. Five hypothetical scenarios representing alternative programmatic approaches during the period from 2013 to 2023 were developed with local staff. Bayesian uncertainty analyses were undertaken to explicitly acknowledge the uncertainty around key epidemiologic parameters, and an economic evaluation was performed. With continuation of existing programmatic strategies, overall TB incidence remained stable at 555 cases per 100,000 population per year (95% simulation interval (SI): 420, 807), but the proportion of incident cases attributable to MDR-TB increased from 16% to 35%. Comprehensive, provincewide strengthening of existing programs reduced incidence to 353 cases per 100,000 population per year (95% SI: 246, 558), with 46% being cases of MDR-TB, while incorporating programmatic management of MDR-TB into these programs reduced incidence to 233 cases per 100,000 population per year (95% SI: 198, 269) with 14% MDR-TB. Most economic costs were due to hospitalization during the intensive treatment phase. Broad scale-up of TB control activities in Western Province with incorporation of programmatic management of MDR-TB is vital if control is to be achieved. Community-based treatment approaches are important to reduce the associated economic costs.
Publisher: Springer Science and Business Media LLC
Date: 11-2021
DOI: 10.1038/S41467-021-26558-4
Abstract: During 2020, Victoria was the Australian state hardest hit by COVID-19, but was successful in controlling its second wave through aggressive policy interventions. We calibrated a detailed compartmental model of Victoria’s second wave to multiple geographically-structured epidemic time-series indicators. We achieved a good fit overall and for in idual health services through a combination of time-varying processes, including case detection, population mobility, school closures, physical distancing and face covering usage. Estimates of the risk of death in those aged ≥75 and of hospitalisation were higher than international estimates, reflecting concentration of cases in high-risk settings. We estimated significant effects for each of the calibrated time-varying processes, with estimates for the in idual-level effect of physical distancing of 37.4% (95%CrI 7.2−56.4%) and of face coverings of 45.9% (95%CrI 32.9−55.6%). That the multi-faceted interventions led to the dramatic reversal in the epidemic trajectory is supported by our results, with face coverings likely particularly important.
Publisher: Cold Spring Harbor Laboratory
Date: 26-06-2020
DOI: 10.1101/2020.06.26.173104
Abstract: Infectiousness heterogeneity among in iduals with tuberculosis (TB) is substantial and is likely to have a significant impact on the long-term dynamics of TB and the effectiveness of interventions. However, there is a gap in capturing heterogeneous infectiousness and evaluating its impact on the effectiveness of interventions. Informed by observed distribution of secondary infections, we constructed a deterministic model of TB transmission using ordinary differential equations. The model incorporated assumption of heterogeneous infectiousness with three levels of infectivity, namely non-spreaders, low-spreaders and super-spreaders. We evaluated the effectiveness of dynamic transmission untargeted and targeted implementation of an intervention intended to represent active case finding with a point-of-care diagnostic tool. The simulated intervention detected 20% of all TB patients who would otherwise have been missed by the health system during their disease episode and was compared across four epidemiological scenarios. Our model suggested that targeting the active case finding intervention towards super-spreaders was more effective than untargeted intervention in all setting scenarios, with more effectiveness in settings with low case detection and high transmission intensity. For instance, a targeted intervention achieved a 42.2% reduction in TB incidence, while the untargeted intervention achieved only a 20.7% reduction over 20 years, given the same number of people treated. Although the most marked impact on equilibrium TB incidence came from the rate of late reactivation, the proportion of super-spreaders and their relative infectiousness had shown substantial impact. Targeting active case-finding interventions to highly infectious cases likely to be particularly beneficial in settings where case detection is poor. Heterogeneity-related parameters had an equivalent effect to several other parameters that have been established as being very important to TB transmission dynamics.
Publisher: BMJ
Date: 03-2020
DOI: 10.1136/BMJOPEN-2019-034845
Abstract: To design a linked hospital database using administrative and clinical information to describe associations that predict infectious diseases outcomes, including long-term mortality. A retrospective cohort of Townsville Hospital inpatients discharged with an International Classification of Diseases and Related Health Problems 10th Revision Australian Modification code for an infectious disease between 1 January 2006 and 31 December 2016 was assembled. This used linked anonymised data from: hospital administrative sources, diagnostic pathology, pharmacy dispensing, public health and the National Death Registry. A Created Study ID was used as the central identifier to provide associations between the cohort patients and the subsets of granular data which were processed into a relational database. A web-based interface was constructed to allow data extraction and evaluation to be performed using editable Structured Query Language. The database has linked information on 41 367 patients with 378 487 admissions and 1 869 239 diagnostic rocedure codes. Scripts used to create the database contents generated over 24 000 000 database rows from the supplied data. Nearly 15% of the cohort was identified as Aboriginal or Torres Strait Islanders. Invasive staphylococcal, pneumococcal and Group A streptococcal infections and influenza were common in this cohort. The most common comorbidities were smoking (43.95%), diabetes (24.73%), chronic renal disease (17.93%), cancer (16.45%) and chronic pulmonary disease (12.42%). Mortality over the 11-year period was 20%. This complex relational database reutilising hospital information describes a cohort from a single tropical Australian hospital of inpatients with infectious diseases. In future analyses, we plan to explore analyses of risks, clinical outcomes, healthcare costs and antimicrobial side effects in site and organism specific infections.
Publisher: MDPI AG
Date: 16-01-2023
DOI: 10.3390/V15010254
Abstract: Vector control methods are considered effective in averting dengue transmission. However, several factors may modify their impact. Of these controls, chemical methods, in the long run, may increase mosquitoes’ resistance to chemicides, thereby decreasing control efficacy. The biological methods, which may be self-sustaining and very effective, could be h ered by seasonality or heatwaves (resulting in, e.g., loss of Wolbachia infection). The environmental methods that could be more effective than the chemical methods are under-investigated. In this study, a systematic review is conducted to explore the present understanding of the effectiveness of vector control approaches via dengue transmission models.
Publisher: Elsevier BV
Date: 11-2016
Publisher: Oxford University Press (OUP)
Date: 12-2008
DOI: 10.1086/593107
Publisher: Public Library of Science (PLoS)
Date: 09-02-2017
Publisher: Springer Science and Business Media LLC
Date: 06-01-2017
Publisher: Frontiers Media SA
Date: 02-12-2021
Publisher: The Journal of Rheumatology
Date: 06-2012
Publisher: The Royal Society
Date: 12-08-2020
Abstract: Combinations of intense non-pharmaceutical interventions (lockdowns) were introduced worldwide to reduce SARS-CoV-2 transmission. Many governments have begun to implement exit strategies that relax restrictions while attempting to control the risk of a surge in cases. Mathematical modelling has played a central role in guiding interventions, but the challenge of designing optimal exit strategies in the face of ongoing transmission is unprecedented. Here, we report discussions from the Isaac Newton Institute ‘Models for an exit strategy’ workshop (11–15 May 2020). A erse community of modellers who are providing evidence to governments worldwide were asked to identify the main questions that, if answered, would allow for more accurate predictions of the effects of different exit strategies. Based on these questions, we propose a roadmap to facilitate the development of reliable models to guide exit strategies. This roadmap requires a global collaborative effort from the scientific community and policymakers, and has three parts: (i) improve estimation of key epidemiological parameters (ii) understand sources of heterogeneity in populations and (iii) focus on requirements for data collection, particularly in low-to-middle-income countries. This will provide important information for planning exit strategies that balance socio-economic benefits with public health.
Publisher: Springer Science and Business Media LLC
Date: 07-08-2017
Publisher: Elsevier BV
Date: 05-2009
DOI: 10.1016/J.JINF.2009.03.006
Abstract: To assess the influence of acetyl-salicylic acid (ASA) on clinical outcomes in Staphylococcus aureus infective endocarditis (SA-IE). The International Collaboration on Endocarditis - Prospective Cohort Study database was used in this observational study. Multivariable analysis of the SA-IE cohort compared outcomes in patients with and without ASA use, adjusting for other predictive variables, including: age, diabetes, hemodialysis, cancer, pacemaker, intracardiac defibrillator and methicillin resistance. Data were analysed from 670 patients, 132 of whom were taking ASA at the time of SA-IE diagnosis. On multivariable analysis, ASA usage was associated with a significantly decreased overall rate of acute valve replacement surgery (OR 0.58 [95% CI 0.35-0.97] p<0.04), particularly where valvular regurgitation, congestive heart failure or periannular abscess was the indication for such surgery (OR 0.46 [0.25-0.86] p<0.02). There was no reduction in the overall rates of clinically apparent embolism with prior ASA usage, and no increase in hemorrhagic strokes in ASA-treated patients. In this multinational prospective observational cohort, recent ASA usage was associated with a reduced occurrence of acute valve replacement surgery in SA-IE patients. Future investigations should focus on ASA's prophylactic and therapeutic use in high-risk and newly diagnosed patients with SA bacteremia and SA-IE, respectively.
Publisher: Cold Spring Harbor Laboratory
Date: 07-03-2021
DOI: 10.1101/2021.03.03.21252859
Abstract: The Marshall Islands implemented ambitious population-based screening programs for latent and active tuberculosis in 2017 and 2018. These interventions’ long-term effects remain to be estimated. To predict the long-term impact of the previous interventions and identify strategies to drive tuberculosis towards elimination. We built a transmission model of tuberculosis informed by local data to capture the epidemic’s historical dynamics. We used the model to project the future epidemic trajectory following the screening interventions, as well as considering a counterfactual scenario with no intervention. We also simulated future scenarios including periodic interventions similar to those previously implemented, to assess the feasibility of reaching the End TB Strategy targets and tuberculosis pre-elimination. The 2017-2018 screening activities were estimated to have reduced tuberculosis incidence and mortality by more than one third in 2020, and are predicted to achieve the End TB Strategy milestone of 50% incidence reduction by 2025 compared to 2015. Interventions had a considerably greater impact when in iduals were also screened for latent infection than active case finding alone. Such combined programs implemented at the national level could achieve tuberculosis pre-elimination by 2035 if repeated every two years, and around 2045 if repeated every five years. We predict that it is possible to achieve tuberculosis pre-elimination by 2035 in the Marshall Islands through periodic repetition of the same ambitious interventions as those previously implemented. Including latent infection testing in active screening activities will be a critical pillar for achieving these ambitious goals.
Publisher: Elsevier BV
Date: 03-2017
DOI: 10.1016/J.IJID.2017.01.031
Abstract: Multidrug-resistant tuberculosis (MDR-TB) is a threat to tuberculosis (TB) control. To guide TB control, it is essential to understand the extent to which and the circumstances in which MDR-TB will replace drug-susceptible TB (DS-TB) as the dominant phenotype. The issue was examined by assessing evidence from genomics, pharmacokinetics, and epidemiology studies. This evidence was then synthesized into a mathematical model. This model considers two TB strains, one with and one without an MDR phenotype. It was considered that intrinsic transmissibility may be different between the two strains, as may the control response including the detection, treatment failure, and default rates. The outcomes were explored in terms of the incidence of MDR-TB and time until MDR-TB surpasses DS-TB as the dominant strain. The ability of MDR-TB to dominate DS-TB was highly sensitive to the relative transmissibility of the resistant strain however, MDR-TB could dominate even when its transmissibility was modestly reduced (to between 50% and 100% as transmissible as the DS-TB strain). This model suggests that it may take decades or more for strain replacement to occur. It was also found that while the lification of resistance is the early cause of MDR-TB, this will rapidly give way to person-to-person transmission.
Publisher: Oxford University Press (OUP)
Date: 09-03-2015
Publisher: Oxford University Press (OUP)
Date: 03-2009
DOI: 10.1086/597012
Publisher: Springer Science and Business Media LLC
Date: 11-10-2018
Publisher: Cambridge University Press (CUP)
Date: 17-01-2018
DOI: 10.1017/S0950268817003041
Abstract: We performed a systematic review and meta-analyses of studies assessing tuberculosis (TB) patient-related risk factors for transmission of Mycobacterium tuberculosis infection. Meta-analyses were conducted for sputum smear-positivity, lung cavitation and HIV seropositivity of index patients with both crude and adjusted odds ratios (AORs) pooled using random effect models. Thirty-seven studies were included in the review. We found that demographic characteristics such as age and sex were not significant risk factors, while behaviours such as smoking and alcohol intake were associated with infectiousness although inconsistently. Treatment delay of days was a significant predictor of greater infectiousness. Contacts of sputum smear-positive index patients were found to be more likely to be infected than contacts of sputum smear-negative patients, with a pooled AOR of 2.15 (95% confidence interval (CI) 1.47–3.17, I 2 = 38%). Similarly, contacts of patients with the cavitary disease were around twice as likely to be infected as contacts of patients without cavitation (pooled AOR 1.9, 95% CI 1.26–2.84, I 2 = 63%). In contrast, HIV seropositive patients were associated with few contact infections than HIV seronegative patients (AOR 0.45, 95% CI 0.26–0.80, I 2 = 52%). In conclusion, behavioural and clinical characteristics of TB patients can be used to identify highly infectious patients for targeted interventions.
Publisher: Wiley
Date: 05-07-2018
DOI: 10.1111/TMI.13118
Abstract: Papua New Guinea (PNG) has an emerging tuberculosis (TB) epidemic which has become a national public health priority. In Western Province, there are few data about TB outside Daru and the South Fly District. This study describes the epidemiology of TB diagnosed at Balimo District Hospital (BDH) in the Middle Fly District of Western Province, PNG. All patients (n = 1614) diagnosed with TB at BDH from April 2013 to February 2017 were recorded. Incidence of reported new cases was calculated for the combined Balimo Urban and Gogodala Rural local level government areas. Analyses investigated patient demographic and clinical information, differences between pulmonary and extrapulmonary TB patients, and predictors of treatment failure. The average case notification rate (2014-2016) was 727 TB cases per 100 000 people per year. One-quarter of TB cases were in children, and 77.1% of all cases had an extrapulmonary TB diagnosis. There was a 1:1.1 ratio of female to male TB cases. When comparing pulmonary and extrapulmonary TB patients, extrapulmonary TB was more likely in those aged up to 14 years and over 54 years. Extrapulmonary TB was more likely in new patients, and pulmonary TB more likely in previously treated patients. Residence in rural regions was associated with treatment failure. There is a high burden of TB in the Balimo region, including a very high proportion of extrapulmonary TB. These factors emphasise the importance of BDH as the primary hospital for TB cases in the Balimo region and the Middle Fly District, and the need for resources and staff to manage both drug-susceptible and drug-resistant TB cases.
Publisher: Public Library of Science (PLoS)
Date: 23-09-2016
Publisher: Elsevier BV
Date: 12-2015
Publisher: Oxford University Press (OUP)
Date: 06-09-2016
DOI: 10.1093/CID/CIW610
Abstract: Delayed antifungal therapy for invasive candidiasis (IC) contributes to poor outcomes. Predictive risk models may allow targeted antifungal prophylaxis to those at greatest risk. A prospective cohort study of 6685 consecutive nonneutropenic patients admitted to 7 Australian intensive care units (ICUs) for ≥72 hours was performed. Clinical risk factors for IC occurring prior to and following ICU admission, colonization with Candida species on surveillance cultures from 3 sites assessed twice weekly, and the occurrence of IC ≥72 hours following ICU admission or ≤72 hours following ICU discharge were measured. From these parameters, a risk-predictive model for the development of ICU-acquired IC was then derived. Ninety-six patients (1.43%) developed ICU-acquired IC. A simple summation risk-predictive model using the 10 independently significant variables associated with IC demonstrated overall moderate accuracy (area under the receiver operating characteristic curve = 0.82). No single threshold score could categorize patients into clinically useful high- and low-risk groups. However, using 2 threshold scores, 3 patient cohorts could be identified: those at high risk (score ≥6, 4.8% of total cohort, positive predictive value [PPV] 11.7%), those at low risk (score ≤2, 43.1% of total cohort, PPV 0.24%), and those at intermediate risk (score 3-5, 52.1% of total cohort, PPV 1.46%). Dichotomization of ICU patients into high- and low-risk groups for IC risk is problematic. Categorizing patients into high-, intermediate-, and low-risk groups may more efficiently target early antifungal strategies and utilization of newer diagnostic tests.
Publisher: Public Library of Science (PLoS)
Date: 09-12-2022
DOI: 10.1371/JOURNAL.PONE.0266436
Abstract: Drug-resistant tuberculosis (DR-TB) is an ongoing challenge in the Torres Strait Islands (TSI) / Papua New Guinea (PNG) border region. Treatment success rates have historically been poor for patients diagnosed with DR-TB, leading to increased transmission. This study aimed to identify variables associated with unfavourable outcome in patients diagnosed with DR-TB to inform programmatic improvements. A retrospective study of all DR-TB cases who presented to Australian health facilities in the Torres Strait between 1 March 2000 and 31 March 2020 was performed. This time period covers four distinct TB programmatic approaches which reflect Australian and Queensland Government decisions on TB management in this remote region. Univariate and multivariate predictors of unfavourable outcome were analysed. Unfavourable outcome was defined as lost to follow up, treatment failure and death. Successful outcome was defined as cure and treatment completion. In total, 133 patients with resistance to at least one TB drug were identified. The vast majority (123/133 92%) of DR-TB patients had pulmonary involvement and of these, 41% (50/123) had both pulmonary and extrapulmonary TB. Unfavourable outcomes were observed in 29% (39/133) of patients. Patients living with human immunodeficiency virus, renal disease or diabetes (4/133 4/133 3/133) had an increased frequency of unfavourable outcome ( p .05), but the numbers were small. Among all 133 DR-TB patients, 41% had a low lymphocyte count, which was significantly associated with unfavourable outcome ( p .05). We noted a 50% increase in successful outcomes achieved in the 2016–2020 programmatic period, compared to earlier periods (OR 5.3, 95% Confidence Interval [1.3, 20.4]). Being a close contact of a known TB case was associated with improved outcome. While DR-TB treatment outcomes have improved over time, enhanced surveillance for DR-TB, better cross border collaboration and consistent diagnosis and management of comorbidities and other risk factors should further improve patient care and outcomes.
Publisher: Elsevier BV
Date: 02-2018
DOI: 10.1016/J.MBS.2017.12.006
Abstract: We introduce and analyze coupled, multi-strain epidemic models designed to simulate the emergence and dissemination of mutant (e.g. drug-resistant) pathogen strains. In particular, we investigate the mathematical and biological properties of a general class of multi-strain epidemic models in which the infectious compartments of each strain are coupled together in a general manner. We derive explicit expressions for the basic reproduction number of each strain and highlight their importance in regulating the system dynamics (e.g. the potential for an epidemic outbreak) and the existence of nonnegative endemic solutions. Importantly, we find that the basic reproduction number of each strain is independent of the mutation rates between the strains - even under quite general assumptions for the form of the infectious compartment coupling. Moreover, we verify that the coupling term promotes strain coexistence (as an extension of the competitive exclusion principle) and demonstrate that the strain with the greatest reproductive capacity is not necessarily the most prevalent. Finally, we briefly discuss the implications of our results for public health policy and planning.
Publisher: Wiley
Date: 06-01-2017
DOI: 10.1111/TMI.12826
Abstract: Multidrug-resistant tuberculosis (MDR-TB) is an emerging public health problem in Ethiopia. The aim of this study was to assess MDR-TB treatment outcomes and determine predictors of poor treatment outcomes in north-west Ethiopia. A retrospective cohort study was conducted using all MDR-TB patients who were enrolled at Gondar University Hospital since the establishment of the MDR-TB programme in 2010. A Cox proportional hazard model was used to identify the predictors of time to poor treatment outcomes, which were defined as death or treatment failure. Of the 242 patients who had complete records, 131 (54%) were cured, 23 (9%) completed treatment, 31 (13%) died, four (2%) experienced treatment failure, 27 (11%) were lost to follow-up, six (2%) transferred out, and 20 (8%) were still on treatment at the time of analysis. The overall cumulative probability survival of the patients at the end of treatment (which was 24 months in duration) was 80% (95% CI: 70%, 87%). The proportion of patients with poor treatment outcomes increased over time from 6% per person-year (PY) during 2010-2012, to 12% per PY during 2013-2015. The independent predictors of time to poor treatment outcome were being anaemic [AHR = 4.2 95% CI: 1.1, 15.9] and being a farmer [AHR = 2.2 95% CI: 1.0, 4.9]. Overall, in north-west Ethiopia, the MDR-TB treatment success rate was high. However, poor treatment outcomes have gradually increased since 2012. Being a farmer and being anaemic were associated with poor treatment outcomes. It would be beneficial to assess other risk factors that might affect treatment outcomes such as co-infection with malaria, poverty and other socio-economic and biological risk factors.
Publisher: Centers for Disease Control and Prevention (CDC)
Date: 06-2011
Publisher: Springer Science and Business Media LLC
Date: 29-06-2011
Publisher: Cold Spring Harbor Laboratory
Date: 07-04-2021
DOI: 10.1101/2021.04.03.21254866
Abstract: Victoria has been Australia’s hardest hit state by the COVID-19 pandemic, but was successful in reversing its second wave of infections through aggressive policy interventions. The clear reversal in the epidemic trajectory combined with information on the timing and geographical scope of policy interventions offers the opportunity to estimate the relative contribution of each change. We developed a compartmental model of the COVID-19 epidemic in Victoria that incorporated age and geographical structure, and calibrated it to data on case notifications, deaths and health service needs according to the administrative isions of Victoria’s healthcare, termed clusters. We achieved a good fit to epidemiological indicators, at both the state level and for in idual clusters, through a combination of time-varying processes that included changes to case detection rates, population mobility, school closures, seasonal forcing, physical distancing and use of face coverings. Estimates of the risk of hospitalisation and death among persons with disease that were needed to achieve this close fit were markedly higher than international estimates, likely reflecting the concentration of the epidemic in groups at particular risk of adverse outcomes, such as residential facilities. Otherwise, most fitted parameters were consistent with the existing literature on COVID-19 epidemiology and outcomes. We estimated a significant effect for each of the calibrated time-varying processes on reducing the risk of transmission per contact, with broad estimates of the reduction in transmission risk attributable to seasonal forcing (27.8%, 95% credible interval [95%CI] 9.26-44.7% for mid-summer compared to mid-winter), but narrower estimates for the in idual-level effect of physical distancing of 12.5% (95%CI 5.69-27.9%) and of face coverings of 39.1% (95%CI 31.3-45.8%). That the multi-factorial public health interventions and mobility restrictions led to the dramatic reversal in the epidemic trajectory is supported by our model results, with the mandatory face coverings likely to have been particularly important.
Publisher: The Royal Society
Date: 03-2015
Abstract: Hepatitis C virus (HCV) reinfection rates are probably underestimated due to reinfection episodes occurring between study visits. A Markov model of HCV reinfection and spontaneous clearance was fitted to empirical data. Bayesian post-estimation was used to project reinfection rates, reinfection spontaneous clearance probability and duration of reinfection. Uniform prior probability distributions were assumed for reinfection rate (more than 0), spontaneous clearance probability (0–1) and duration (0.25–6.00 months). Model estimates were 104 per 100 person-years (95% CrI: 21–344), 0.84 (95% CrI: 0.59–0.98) and 1.3 months (95% CrI: 0.3–4.1) for reinfection rate, spontaneous clearance probability and duration, respectively. Simulation studies were used to assess model validity, demonstrating that the Bayesian model estimates provided useful information about the possible sources and magnitude of bias in epidemiological estimates of reinfection rates, probability of reinfection clearance and duration or reinfection. The quality of the Bayesian estimates improved for larger s les and shorter test intervals. Uncertainty in model estimates notwithstanding, findings suggest that HCV reinfections frequently and quickly result in spontaneous clearance, with many reinfection events going unobserved.
Publisher: Rural and Remote Health
Date: 10-02-2021
DOI: 10.22605/RRH6317
Publisher: Cold Spring Harbor Laboratory
Date: 11-10-2020
DOI: 10.1101/2020.10.08.20208108
Abstract: In anticipation of COVID-19 vaccine deployment, we use an age-structured mathematical model to investigate the benefits of optimizing age-specific dose allocation to suppress the transmission, morbidity and mortality of SARS-CoV-2 and the associated disease, COVID-19. To minimize transmission, we find that the highest priority in iduals across 179 countries are typically those between 30 and 59 years of age because of their high contact rates and higher risk of infection and disease. Conversely, morbidity and mortality are initially most effectively reduced by targeting 60+ year olds who are more likely to experience severe disease. However, when population-level coverage is sufficient — such that herd immunity can be achieved through targeted dose allocation — prioritizing middle-aged in iduals becomes the most effective strategy to minimize hospitalizations and deaths. For each metric considered, we show that optimizing the allocation of vaccine doses can more than double their effectiveness.
Publisher: Cold Spring Harbor Laboratory
Date: 19-07-2021
DOI: 10.1101/2021.07.16.21260642
Abstract: The Australian National Cabinet four-step plan to transition to post-pandemic re-opening begins with vaccination to achieve herd protection and protection of the health system against a surge in COVID-19 cases. Assuming a pre-vaccination reproduction number for the Delta variant of 5, we show that for the current Mixed program of vaccinating over 60s with AstraZeneca and 16-60s with Pfizer we would not achieve herd immunity. We would need to cover 85% of the population (including many 5-16 year-olds to achieve herd immunity). At lower reproduction number of 3 and our current Mixed strategy, we can achieve herd immunity without vaccinating 5-15 year olds. This will be achieved at a 60% coverage pursuing a strategy targetting high transmitters or 70% coverage using a strategy targetting the vulnerable first. A reproduction number of 7 precludes achieving herd immunity, however vaccination is able to prevent 75% of deaths compared with no vaccination. We also examine the impact of vaccination on death in the event that herd immunity is not achieved. Direct effects of vaccination on reducing death are very good for both Pfizer and AstraZeneca vaccines. However we estimate that the Mixed or Pfizer program performs better than the AstraZeneca program. Furthermore, vaccination levels below the herd immunity threshold can lead to substantial (albeit incomplete) indirect protection for both vaccinated and unvaccinated populations. Given the potential for not reaching herd immunity, we need to consider what level of severe disease and death is acceptable, balanced against the consequences of ongoing aggressive control strategies.
Publisher: Elsevier BV
Date: 2016
Publisher: Cambridge University Press (CUP)
Date: 2019
DOI: 10.1017/S0950268819001857
Abstract: As Bulgaria transitions away from Global Fund grant, robust estimates of the comparative impact of the various response strategies under consideration are needed to ensure sustained effectiveness of the tuberculosis (TB) programme. We tailored an established mathematical model for TB control to the epidemic in Bulgaria to project the likely outcomes of seven intervention scenarios. Under existing programmatic conditions projected forward, the country's targets for achieving TB elimination in the coming decades will not be achieved. No interventions under consideration were predicted to accelerate the baseline projected reduction in epidemiological indicators significantly. Discontinuation of the ‘Open Doors’ program and activities of non-governmental organisations would result in a marked exacerbation of the epidemic (increasing incidence in 2035 by 6–8% relative to baseline conditions projected forward). Changing to a short course regimen for multidrug-resistant TB (MDR-TB) would substantially decrease MDR-TB mortality (by 21.6% in 2035 relative to baseline conditions projected forward). Changing to ambulatory care for eligible patients would not affect TB burden but would be markedly cost-saving. In conclusion, Bulgaria faces important challenges in transitioning to a primarily domestically-financed TB programme. The country should consider maintaining currently effective programs and shifting towards ambulatory care to ensure program sustainability.
Publisher: The Royal Society
Date: 23-02-2011
Abstract: We present a method for estimating reproduction numbers for adults and children from daily onset data, using pandemic influenza A(H1N1) data as a case study. We investigate the impact of different underlying transmission assumptions on our estimates, and identify that asymmetric reproduction matrices are often appropriate. Under-reporting of cases can bias estimates of the reproduction numbers if reporting rates are not equal across the two age groups. However, we demonstrate that the estimate of the higher reproduction number is robust to disproportionate data-thinning. Applying the method to 2009 pandemic influenza H1N1 data from Japan, we demonstrate that the reproduction number for children was considerably higher than that of adults, and that our estimates are insensitive to our choice of reproduction matrix.
Publisher: Informa UK Limited
Date: 16-12-2015
Publisher: American Society of Tropical Medicine and Hygiene
Date: 06-12-2017
Publisher: Elsevier BV
Date: 12-2017
DOI: 10.1016/J.EPIDEM.2017.06.002
Abstract: Although different structures are used in modern tuberculosis (TB) models to simulate TB latency, it remains unclear whether they are all capable of reproducing the particular activation dynamics empirically observed. We aimed to determine which of these structures replicate the dynamics of progression accurately. We reviewed 88 TB-modelling articles and classified them according to the latency structure employed. We then fitted these different models to the activation dynamics observed from 1352 infected contacts diagnosed in Victoria (Australia) and Amsterdam (Netherlands) to obtain parameter estimates. Six different model structures were identified, of which only those incorporating two latency compartments were capable of reproducing the activation dynamics empirically observed. We found important differences in parameter estimates by age. We also observed marked differences between our estimates and the parameter values used in many previous models. In particular, when two successive latency phases are considered, the first period should have a duration that is much shorter than that used in previous studies. In conclusion, structures incorporating two latency compartments and age-stratification should be employed to accurately replicate the dynamics of TB latency. We provide a catalogue of parameter values and an approach to parameter estimation from empiric data for calibration of future TB-models.
Publisher: Elsevier BV
Date: 03-2020
Publisher: Elsevier BV
Date: 10-2019
Publisher: Springer Science and Business Media LLC
Date: 27-01-2015
Publisher: Springer Science and Business Media LLC
Date: 25-05-2010
Publisher: AMPCo
Date: 08-12-2021
DOI: 10.5694/MJA2.50894
Publisher: Public Library of Science (PLoS)
Date: 10-11-2017
Publisher: Elsevier BV
Date: 12-2008
Publisher: Elsevier BV
Date: 10-2018
Publisher: Hindawi Limited
Date: 19-10-2022
DOI: 10.1111/TBED.14725
Abstract: Leptospirosis is the most common bacterial zoonosis globally. The pathogen, Leptospira spp., is primarily associated with rodent reservoirs. However, a wide range of other species has been implicated as reservoirs or dead-end hosts. We conducted a survey for Leptospira spp. in bats and rodents from Papua New Guinea. Kidney s les were collected from 97 pteropodid bats (five species), 37 insectivorous bats from four different families (six species) and 188 rodents (two species). Leptospires were detected in a high proportion of pteropodid bats, including Nyctimene cf. albiventer (35%), Macroglossus minimus (34%) and Rousettus lexicaudatus (36%). Partial sequencing of the secY gene from rodent and bat leptospires showed host species clustering, with Leptospira interrogans and L. weilii detected in rodents and L. kirschneri and a potential novel species of Leptospira detected in bats. Further research is needed in Papua New Guinea and other locales in the Pacific region to gain a better understanding of the circulation dynamics of leptospires in reservoir species and the risks to public and veterinary health.
Publisher: Frontiers Media SA
Date: 29-05-2020
Publisher: Cambridge University Press (CUP)
Date: 2020
DOI: 10.1017/S0950268820001740
Abstract: Following the importation of coronavirus disease (COVID-19) into Nigeria on 27 February 2020 and then the outbreak, the question is: How do we anticipate the progression of the ongoing epidemic following all the intervention measures put in place? This kind of question is appropriate for public health responses and it will depend on the early estimates of the key epidemiological parameters of the virus in a defined population. In this study, we combined a likelihood-based method using a Bayesian framework and compartmental model of the epidemic of COVID-19 in Nigeria to estimate the effective reproduction number ( R ( t )) and basic reproduction number ( R 0 ) – this also enables us to estimate the initial daily transmission rate ( β 0 ). We further estimate the reported fraction of symptomatic cases. The models are applied to the NCDC data on COVID-19 symptomatic and death cases from 27 February 2020 and 7 May 2020. In this period, the effective reproduction number is estimated with a minimum value of 0.18 and a maximum value of 2.29. Most importantly, the R ( t ) is strictly greater than one from 13 April till 7 May 2020. The R 0 is estimated to be 2.42 with credible interval: (2.37–2.47). Comparing this with the R ( t ) shows that control measures are working but not effective enough to keep R ( t ) below 1. Also, the estimated fraction of reported symptomatic cases is between 10 and 50%. Our analysis has shown evidence that the existing control measures are not enough to end the epidemic and more stringent measures are needed.
Publisher: Springer Science and Business Media LLC
Date: 23-02-2021
DOI: 10.1038/S41598-021-83768-Y
Abstract: Tuberculosis (TB) is a major public health problem in Bangladesh. Although the National TB control program of Bangladesh is implementing a comprehensive expansion of TB control strategies, logistical challenges exist, and there is significant uncertainty concerning the disease burden. Mathematical modelling of TB is considered one of the most effective ways to understand the dynamics of infection transmission and allows quantification of parameters in different settings, including Bangladesh. In this study, we present a two-strain mathematical modelling framework to explore the dynamics of drug-susceptible (DS) and multidrug-resistant (MDR) TB in Bangladesh. We calibrated the model using DS and MDR-TB annual incidence data from Bangladesh from years 2001 to 2015. Further, we performed a sensitivity analysis of the model parameters and found that the contact rate of both strains had the largest influence on the basic reproduction numbers $${\\text{R}}_{{0{\\text{s}}}}$$ R 0 s and $${\\text{R}}_{{0{\\text{m}}}}$$ R 0 m of DS and MDR-TB, respectively. Increasingly powerful intervention strategies were developed, with realistic impact and coverage determined with the help of local staff. We simulated for the period from 2020 to 2035. Here, we projected the DS and MDR-TB burden (as measured by the number of incident cases and mortality) under a range of intervention scenarios to determine which of these scenario is the most effective at reducing burden. Of the single-intervention strategies, enhanced case detection is the most effective and prompt in reducing DS and MDR-TB incidence and mortality in Bangladesh and that with GeneXpert testing was also highly effective in decreasing the burden of MDR-TB. Our findings also suggest combining additional interventions simultaneously leads to greater effectiveness, particularly for MDR-TB, which we estimate requires a modest investment to substantially reduce, whereas DS-TB requires a strong sustained investment.
Publisher: AMPCo
Date: 08-2009
Publisher: Elsevier BV
Date: 09-2020
Publisher: Elsevier BV
Date: 09-2020
Publisher: Centers for Disease Control and Prevention (CDC)
Date: 09-2011
Publisher: Public Library of Science (PLoS)
Date: 11-2013
Publisher: Springer Science and Business Media LLC
Date: 18-11-2016
Publisher: Hindawi Limited
Date: 15-04-2019
DOI: 10.1111/TBED.13188
Abstract: Ethiopia is one of 30-high burden multidrug-resistant tuberculosis (MDR-TB) countries globally. The aim of this study was to describe the characteristics of patients with MDR-TB and to investigate risk factors for MDR-TB relative to having drug-susceptible tuberculosis (TB), in northwest Ethiopia. A hospital-based, unmatched case-control study was conducted. Cases were all MDR-TB patients (i.e., resistant to at least rif icin and isoniazid) who were confirmed by culture and drug-susceptibility testing whilst enrolled on treatment at Gondar University Hospital. Controls were all drug-susceptible tuberculosis (DS-TB) patients who were confirmed by Gene Xpert MTB/RIF at Gondar University Hospital. Univariable and multivariable logistic regression models were used for comparisons, and odds ratios with 95% confidence intervals (CI) were computed to measure the strength of association between the dependent and independent variables. A total of 452 patients (242 MDR-TB and 210 DS-TB) were included in this study. The mean age of the study participants was 33 years (SD ± 14 years). Approximately one-fifth (78, 17%) of all study participants were human immunodeficiency virus (HIV) positive 21% (51) of cases and 13% (27) of controls. Risk factors associated with MDR-TB were a history of previous TB treatment (Adjusted Odds Ratio (AOR): 83.8 95% CI: 40.7, 172.5), low educational status (AOR: 5.32 95% CI: 1.43, 19.81) and ages less than 20 years (AOR: 9.01 95% CI: 2.30, 35.25) and 21-30 years (AOR: 2.61 95% CI: 1.02, 6.64). HIV infection was also significantly associated with MDR-TB among new TB patients (AOR: 5.55 95% CI: 1.17, 26.20). This study shows that clinical and demographic features can be used to indicate higher risks of drug resistance in this setting.
Publisher: MDPI AG
Date: 08-01-2021
Abstract: Arthropod-borne viruses (Arboviruses) continue to generate significant health and economic burdens for people living in endemic regions. Of these viruses, some of the most important (e.g., dengue, Zika, chikungunya, and yellow fever virus), are transmitted mainly by Aedes mosquitoes. Over the years, viral infection control has targeted vector population reduction and inhibition of arboviral replication and transmission. This control includes the vector control methods which are classified into chemical, environmental, and biological methods. Some of these control methods may be largely experimental (both field and laboratory investigations) or widely practised. Perceptively, one of the biological methods of vector control, in particular, Wolbachia-based control, shows a promising control strategy for eradicating Aedes-borne arboviruses. This can either be through the artificial introduction of Wolbachia, a naturally present bacterium that impedes viral growth in mosquitoes into heterologous Aedes aegypti mosquito vectors (vectors that are not natural hosts of Wolbachia) thereby limiting arboviral transmission or via Aedes albopictus mosquitoes, which naturally harbour Wolbachia infection. These strategies are potentially undermined by the tendency of mosquitoes to lose Wolbachia infection in unfavourable weather conditions (e.g., high temperature) and the inhibitory competitive dynamics among co-circulating Wolbachia strains. The main objective of this review was to critically appraise published articles on vector control strategies and specifically highlight the use of Wolbachia-based control to suppress vector population growth or disrupt viral transmission. We retrieved studies on the control strategies for arboviral transmissions via arthropod vectors and discussed the use of Wolbachia control strategies for eradicating arboviral diseases to identify literature gaps that will be instrumental in developing models to estimate the impact of these control strategies and, in essence, the use of different Wolbachia strains and features.
Publisher: Elsevier BV
Date: 02-2016
DOI: 10.1016/J.CHEST.2015.11.017
Abstract: It is often stated that the lifetime risk of developing active TB after an index infection is 5% to 10%, one-half of which accrues in the 2 to 5 years following infection. The goal of this study was to determine whether such estimates are consistent with local programmatic data. This study included close contacts of in iduals with active pulmonary TB notified in the Australian state of Victoria from January 1, 2005, to December 31, 2013, who we deemed to have been infected as a result of their exposure. Survival analysis was first performed on the assumption of complete follow-up through to the end of the study period. The analysis was then repeated with imputation of censorship for migration, death, and preventive treatment, using local mortality and migration data combined with programmatic data on the administration of preventive therapy. Of 613 infected close contacts, 67 (10.9%) developed active TB during the study period. Assuming complete follow-up, the 1,650-day cumulative hazard was 11.5% (95% CI, 8.9-14.1). With imputation of censorship for death, migration, and preventive therapy, the median 1,650-day cumulative hazard over 10,000 simulations was 14.5% (95% CI, 11.1-17.9). Most risk accrued in the first 5 months after infection, and risk was greatest in the group aged < 5 years, reaching 56.0% with imputation, but it was also elevated in older children (27.6% in the group aged 5-14 years). The risk of active TB following infection is several-fold higher than traditionally accepted estimates, and it is particularly high immediately following infection and in children.
Publisher: Elsevier BV
Date: 10-2015
DOI: 10.1016/J.IJANTIMICAG.2015.05.015
Abstract: This study assessed urinary Escherichia coli antibiotic susceptibility patterns in Tasmania, Australia, and examined their association with community antibiotic use. The susceptibility profiles of all urinary E. coli isolates collected in Tasmania between January 2010 and December 2012 were included. The amount of Pharmaceutical Benefits Scheme (PBS)-subsidised use of amoxicillin, amoxicillin/clavulanic acid (AMC), cefalexin, norfloxacin, ciprofloxacin and trimethoprim was retrieved (at the Tasmanian population level) and the number of defined daily doses per 1000 population per day in Tasmania for these antibiotics was calculated for each month during the study period. Antimicrobial susceptibility data were assessed for changes over time in the 3-year study period. Antimicrobial use and susceptibility data were assessed for seasonal differences and lag in resistance following antibiotic use. Excluding duplicates, 28145 E. coli isolates were included. Resistance levels were low 35% of isolates were non-susceptible to amoxicillin, 14% were non-susceptible to trimethoprim and <5% were non-susceptible to AMC, cefalexin, gentamicin and norfloxacin. Amoxicillin use increased by 35% during winter/spring compared with summer/autumn, and AMC use increased by 21%. No seasonal variation in quinolone use or resistance was detected. The low levels of antimicrobial resistance identified may relate to Tasmania's isolated geographical location. Significant seasonal variation in amoxicillin and AMC use is likely to be due to increased use of these antibiotics for treatment of respiratory tract infections in winter. Quinolone use is restricted by the PBS in Australia, which is the likely explanation for the low levels of quinolone use and resistance identified.
Publisher: Elsevier BV
Date: 10-2021
Publisher: Springer Science and Business Media LLC
Date: 08-10-2020
DOI: 10.1038/S41598-020-73819-1
Abstract: Arboviral infections such as dengue, Zika and chikungunya are fast spreading diseases that pose significant health problems globally. In order to control these infections, an intracellular bacterium called Wolbachia has been introduced into wild-type mosquito populations in the hopes of replacing the vector transmitting agent, Aedes aegypti with one that is incapable of transmission. In this study, we developed a Wolbachia transmission model for the novel w Au strain which possesses several favourable traits (e.g., enhanced viral blockage and maintenance at higher temperature) but not cyctoplasmic incompatibility (CI)—when a Wolbachia -infected male mosquito mates with an uninfected female mosquito, producing no viable offspring. This model describes the competitive dynamics between w Au- Wolbachia -infected and uninfected mosquitoes and the role of imperfect maternal transmission. By analysing the system via computing the basic reproduction number(s) and stability properties, the potential of the w Au strain as a viable strategy to control arboviral infections is established. The results of this work show that enhanced maintenance of Wolbachia infection at higher temperatures can overcome the lack of CI induction to support w Au- Wolbachia infected mosquito invasion. This study will support future arboviral control programs, that rely on the introduction of new Wolbachia variants.
Publisher: Cold Spring Harbor Laboratory
Date: 20-05-2020
DOI: 10.1101/2020.05.16.20104471
Abstract: Following the importation of Covid-19 into Nigeria on the 27 February 2020 and then the outbreak, the question is: how do we anticipate the progression of the ongoing epidemics following all the intervention measures put in place? This kind of question is appropriate for public health responses and it will depend on the early estimates of the key epidemiological parameters of the virus in a defined population. In this study, we combined a likelihood-based method using a Bayesian framework and compartmental model of the epidemic of Covid-19 in Nigeria to estimate the effective reproduction number (R(t)) and basic reproduction number (R_0). This also enables us to estimate the daily transmission rate (β) that determines the effect of social distancing. We further estimate the reported fraction of symptomatic cases. The models are applied to the NCDC data on Covid-19 symptomatic and death cases from 27 February 2020 and 7 May 2020. In this period, the effective reproduction number is estimated with a minimum value of 0.18 and a maximum value of 1.78. Most importantly, the R(t) is strictly greater than one from April 13 till 7 May 2020. The R_0 is estimated to be 2.42 with credible interval: (2.37, 2.47). Comparing this with the R(t) shows that control measures are working but not effective enough to keep R(t) below one. Also, the estimated fractional reported symptomatic cases are between 10 to 50%. Our analysis has shown evidence that the existing control measures are not enough to end the epidemic and more stringent measures are needed.
Publisher: AMPCo
Date: 03-2013
DOI: 10.5694/MJA12.11703
Abstract: To determine research priorities of infectious diseases physicians for clinician-initiated randomised controlled trials (RCTs). Online survey of infectious diseases physicians in Australia and New Zealand. Research priorities for, and perceived barriers to, clinician-initiated RCTs. 122/550 infectious diseases physicians (22%) responded to the survey. The five highest ranked proposals for clinician-initiated RCTs were in the areas of prosthetic joint infections, septic arthritis and osteomyelitis of native joints, Staphylococcus aureus bloodstream infections, diabetic foot infections and the treatment of serious multiresistant, gram-negative bacterial infections. Lack of funding was the most important perceived barrier to participation in clinician-initiated RCTs. The research focus of infectious diseases physicians - optimal treatment of commonly encountered serious infections - highlights a lack of well conducted RCTs in this area.
Publisher: Springer Science and Business Media LLC
Date: 20-08-2015
Publisher: American Society for Microbiology
Date: 12-2018
DOI: 10.1128/AAC.01487-18
Abstract: Short-course regimens for multidrug-resistant tuberculosis (MDR-TB) are urgently needed. Limited data suggest that the new drug bedaquiline (BDQ) may have the potential to shorten MDR-TB treatment to less than 6 months when used in conjunction with standard anti-TB drugs.
Publisher: Springer Science and Business Media LLC
Date: 07-03-2022
DOI: 10.1038/S41598-022-07536-2
Abstract: Tuberculosis (TB) is an airborne infectious disease that causes millions of deaths worldwide each year (1.2 million people died in 2019). Alarmingly, several strains of the causative agent, Mycobacterium tuberculosis (MTB)—including drug-susceptible (DS) and drug-resistant (DR) variants—already circulate throughout most developing and developed countries, particularly in Bangladesh, with totally drug-resistant strains starting to emerge. In this study we develop a two-strain DS and DR TB transmission model and perform an analysis of the system properties and solutions. Both analytical and numerical results show that the prevalence of drug-resistant infection increases with an increasing drug use through lification. Both analytic results and numerical simulations suggest that if the basic reproduction numbers of both DS ( $${\\text{R}}_{{0{\\text{s}}}}$$ R 0 s ) and DR ( $${\\text{R}}_{{0{\\text{r}}}}$$ R 0 r ) TB are less than one, i.e. $$\\max \\left[ {{\\text{R}}_{{0{\\text{s}}}} ,{\\text{ R}}_{{0{\\text{r}}}} } \\right] 1,$$ max R 0 s , R 0 r 1 , the disease-free equilibrium is asymptotically stable, meaning that the disease naturally dies out. Furthermore, if $${\\text{R}}_{{0{\\text{r}}}} {\\text{max}}\\left[ {{\\text{R}}_{{0{\\text{s}}}} ,1} \\right]$$ R 0 r max R 0 s , 1 , then DS TB dies out but DR TB persists in the population, and if $${\\text{R}}_{{0{\\text{s}}}} {\\text{max}}\\left[ {{\\text{R}}_{{0{\\text{r}}}} ,1} \\right]$$ R 0 s max R 0 r , 1 both DS TB and DR TB persist in the population. Further, sensitivity analysis of the model parameters found that the transmission rate of both strains had the greatest influence on DS and DR TB prevalence. We also investigated the effect of treatment rates and lification on both DS and DR TB prevalence results indicate that inadequate or inappropriate treatment makes co-existence more likely and increases the relative abundance of DR TB infections.
Publisher: Public Library of Science (PLoS)
Date: 25-05-2016
Publisher: Springer Science and Business Media LLC
Date: 02-10-2017
Publisher: International Union Against Tuberculosis and Lung Disease
Date: 09-2018
Publisher: Oxford University Press (OUP)
Date: 15-11-2009
DOI: 10.1086/644782
Publisher: Elsevier BV
Date: 07-2011
Publisher: Elsevier BV
Date: 07-2018
Publisher: Elsevier BV
Date: 03-2019
Publisher: Springer Science and Business Media LLC
Date: 02-01-2020
Publisher: Public Library of Science (PLoS)
Date: 23-05-2018
Publisher: Elsevier BV
Date: 02-2018
DOI: 10.1016/J.IJID.2017.12.004
Abstract: Tuberculosis (TB) is a serious health problem in Papua New Guinea (PNG) with an estimated 30000 new cases and 3800 deaths each year. In the Balimo region of the Western Province, diagnosis relies on clinical manifestations and on the microscopic detection of acid-fast bacilli (AFB) in sputum smears, a technique with limited sensitivity. A molecular diagnosis assay targeting DNA extracted from archived sputum smear slides collected from the Balimo region (2012-2014) was conducted, without the need for a viable culture. The presence of Mycobacterium sp on 1162 slides prepared from 345 sputum s les was assessed using a real-time PCR (qPCR) approach. The qPCR technique identified the presence of mycobacteria in 35.4% of the smear slides and 59.7% of the tested sputum s les. Poor agreement was observed between the two diagnosis methods (smear AFB microscopy versus qPCR), with 100 AFB-positive sputum s les compared to 206 qPCR-positive sputum s les overall. Treatment was initiated in 90.2% of the smear-positive cases. Unnecessary treatment of 'false-positive' TB cases (AFB-negative/qPCR-negative) was very low (8.6%) and was even lower when the nine patients diagnosed with extrapulmonary TB were excluded from the analysis. However, the prevalence of false-negatives (AFB-negative/qPCR-positive) was high (28.5%). Undetected smear-negative TB is occurring in the Balimo region of PNG, as well as some unnecessary empirical treatment. Molecular methods of diagnosis could greatly reduce the frequency of inappropriate clinical assessment, as well as providing point-of-care diagnosis. This may provide substantial patient and programmatic benefits, including lowering the economic burden on patients from rural areas seeking medical diagnosis in Balimo.
Publisher: Cold Spring Harbor Laboratory
Date: 06-02-2022
DOI: 10.1101/2022.02.05.479210
Abstract: Genomic neighbor typing enables heuristic inference of bacterial lineages and phenotypes from nanopore sequencing data. However, small reference databases may not be sufficiently representative of the ersity of lineages and genotypes present in a collection of isolates. In this study, we explore the use of genomic neighbor typing for surveillance of community-associated Staphylococcus aureus outbreaks in Papua New Guinea (PNG) and Far North Queensland, Australia (FNQ). We developed Sketchy , an implementation of genomic neighbor typing that queries exhaustive whole genome reference databases using MinHash. Evaluations were conducted using nanopore read simulations and six species-wide reference sketches (4832 - 47616 genomes), as well as two S. aureus outbreak data sets sequenced at low depth using a sequential multiplex library protocol on the MinION (n = 160, with matching Illumina data). Heuristic inference of lineages and antimicrobial resistance profiles allowed us to conduct multiplex genotyping in situ at the Papua New Guinea Institute of Medical Research in Goroka, on low-throughput Flongle adapters and using multiple successive libraries on the same MinION flow cell (n = 24 - 48). Comparison to phylogenetically informed genomic neighbor typing with RASE on the dominant outbreak sequence type suggests slightly better performance at predicting lineage-scale genotypes using large sketch sizes, but inferior performance in resolving clade-specific genotypes (methicillin resistance). Sketchy can be used for large-scale bacterial outbreak surveillance and in challenging sequencing scenarios, but improvements to clade-specific genotype inference are needed for diagnostic applications. Sketchy is available open-source at: steinig/sketchy
Publisher: Public Library of Science (PLoS)
Date: 28-11-2007
Publisher: Cold Spring Harbor Laboratory
Date: 30-11-2020
DOI: 10.1101/2020.11.26.20239533
Abstract: The variable efficacy observed in studies of BCG vaccination is incompletely explained by currently accepted hypotheses, such as latitudinal gradient in non-tuberculous mycobacteria exposure. We investigated heterogeneity in BCG vaccination in the context of participant demography, diagnostic approach and TB-related epidemiological context. We updated previous systematic reviews of the effectiveness of BCG vaccination to 31 st December 2018. We employed an identical search strategy and inclusion/exclusion criteria to past reviews, but reclassified several studies and developed an alternative classification system. Of 21 included trials, those recruiting neonates and children aged under five were consistent in demonstrating considerable protection for several years. Trials in high-burden settings with shorter follow-up also showed considerable protection, as did most trials in settings of declining burden with longer follow-up. However, the few trials performed in high-burden settings with longer follow-up showed no protection, sometimes with higher case rates in the vaccinated than the controls in the later follow-up period. The most plausible explanatory hypothesis is that BCG protects against TB that results from exposure shortly after vaccination. However, risk is equivalent or increased when exposure occurs later from vaccination, a phenomenon which is predominantly observed in adults in high-burden settings with longer follow-up. In settings of declining burden, most exposure occurs shortly following vaccination and the sustained protection thereafter represents continued protection against this early exposure. By contrast, in settings of continued intense transmission, initial protection subsequently declines due to repeated exposure to M. tuberculosis or other pathogens.
Publisher: Elsevier BV
Date: 02-2022
Publisher: Elsevier BV
Date: 11-2016
Publisher: Wiley
Date: 03-2002
Publisher: Public Library of Science (PLoS)
Date: 10-11-2015
Publisher: Elsevier BV
Date: 09-2021
Publisher: Elsevier BV
Date: 09-2021
Publisher: AMPCo
Date: 10-2012
DOI: 10.5694/MJA12.10035
Abstract: To estimate the risk of active tuberculosis (TB) in immigrants to VICtoria, Australia, as a function of time since arrival and stratified by age group and region of origin. DESIGN, SETTING AND SUBJECT: Longitudinal study of the incidence of active TB in VICtorian immigrants, excluding New Zealanders, who arrived in Australia between 1975 and 2007. VICtorian immigration data were used to describe annual arrival cohorts by age and region of origin, and TB case notification data for 1995 to 2010 were matched to the cohorts. Survival analysis was performed to determine incidence rates of active TB. Incidence of active TB, stratified by age, region of origin and time since arrival in Australia. Incidence of active TB following immigration to Australia was highly dependent on region of origin, with the highest risks being in immigrants from South Asia and sub-Saharan Africa. For immigrants from high-risk regions (Asia, Africa and the Pacific), the incidence of active TB infection was 100-150 per 100 000 person-years in the first 6 years following immigration. Overall, we estimate that 50% of TB occurred within 7 years of arrival. A bimodal age distribution was evident, with peaks of incidence in 20-24-year-olds and 70-74-year-olds. Our data show that substantial risk of TB in VICtorian immigrants persists well beyond the first 2-3 years following arrival, and that risk is highly dependent on region of origin. The regional dependence suggests that public health strategies would benefit from more refined regional stratification of risk, which could be used to determine risk thresholds for the use of TB prevention strategies and predict rates of TB in Australia following particular patterns of immigration.
Publisher: Springer Science and Business Media LLC
Date: 05-07-2014
Publisher: Springer Science and Business Media LLC
Date: 29-10-2019
DOI: 10.1038/S41598-019-51892-5
Abstract: Tuberculosis remains the world’s leading cause of death from an infectious agent, and is a serious health problem in Papua New Guinea (PNG) with an estimated 36,000 new cases each year. This study describes the genetic ersity of Mycobacterium tuberculosis among tuberculosis patients in the Balimo/Bamu region in the Middle Fly District of Western Province in PNG, and investigates rif icin resistance-associated mutations. Archived Ziehl-Neelsen-stained sputum smears were used to conduct microbead-based spoligotyping and assess genotypic resistance. Among the 162 s les included, 80 (49.4%) generated spoligotyping patterns (n = 23), belonging predominantly to the L2 Lineage (44%) and the L4 Lineage (30%). This is consistent with what has been found in other PNG regions geographically distant from Middle Fly District of Western Province, but is different from neighbouring South-East Asian countries. Rif icin resistance was identified in 7.8% of the successfully sequenced s les, with all resistant s les belonging to the L2/Beijing Lineage. A high prevalence of mixed L2/L4 profiles was suggestive of polyclonal infection in the region, although this would need to be confirmed. The method described here could be a game-changer in resource-limited countries where large numbers of archived smear slides could be used for retrospective (and prospective) studies of M. tuberculosis genetic epidemiology.
Publisher: Elsevier BV
Date: 02-2021
Publisher: MDPI AG
Date: 10-02-2019
DOI: 10.3390/TROPICALMED4010033
Abstract: Papua New Guinea (PNG) has a high burden of tuberculosis (TB), including drug-resistant TB (DR-TB). DR-TB has been identified in patients in Western Province, although there has been limited study outside the provincial capital of Daru. This study focuses on the Balimo region of Western Province, aiming to identify the proportion of DR-TB, and characterise Mycobacterium tuberculosis (MTB) drug resistance-associated gene mutations. Sputum s les were investigated for MTB infection using published molecular methods. DNA from MTB-positive s les was lified and sequenced, targeting the rpoB and katG genes to identify mutations associated with rif icin and isoniazid resistance respectively. A total of 240 sputum s les were collected at Balimo District Hospital (BDH). Of these, 86 were classified as positive based on the results of the molecular assays. For s les where rpoB sequencing was successful, 10.0% (5/50, 95% CI 4.4–21.4%) were considered rif icin-resistant through detection of drug resistance-associated mutations. We have identified high rates of presumptive DR-TB in the Balimo region of Western Province, PNG. These results emphasise the importance of further surveillance, and strengthening of diagnostic and treatment services at BDH and throughout Western Province, to facilitate detection and treatment of DR-TB, and limit transmission in this setting.
Publisher: Wiley
Date: 11-10-2021
DOI: 10.5694/MJA2.51263
Publisher: Wiley
Date: 12-2017
DOI: 10.1111/IMJ.13601
Abstract: Currently, treatment of latent tuberculosis infection (LTBI) in Australia consists most commonly of a 9-month course of isoniazid (9H). A 3-month course of weekly isoniazid and rifapentine (3HP) has been shown to be as effective as 9 months of daily isoniazid, and associated with less hepatotoxicity however, rifapentine is not currently available in Australia. Introduction of this regimen would have apparent advantages for people with LTBI in Victoria by safely shortening duration of LTBI therapy. However, the cost benefit of this new therapeutic approach is uncertain. Cost-analysis of standard and short-course therapy for LTBI in an Australian context. Single-centre randomised controlled trial conducted between December 2013-March 2016. Participants underwent 1:1 randomisation to either a 9-month course of daily isoniazid or a 12-week course of weekly isoniazid and rifapentine. The primary outcome measure was total healthcare system costs (in Australian dollars AUD) per completed course of LTBI therapy. Secondary cost analyses were performed to consider varying assumptions regarding commercial cost of rifapentine. Overall, 34 of 40 (85%) participants in the 9H group and 36/40 (90%) in the 3HR group completed therapy. One patient in the 3HP group was hospitalised for a febrile illness no hospitalisations were recorded in the 9H group. The cost per completed course of 9H was 601 AUD, while that of 3HP was significantly lower at 511 AUD (P < 0.01). This study provides cost analysis evidence to support the use of 3HP for the treatment of LTBI in Australia.
Publisher: Elsevier BV
Date: 10-2013
Publisher: Springer Science and Business Media LLC
Date: 19-02-2008
Publisher: American College of Physicians
Date: 05-05-2009
Publisher: Elsevier BV
Date: 2023
Publisher: Springer Science and Business Media LLC
Date: 08-04-2006
Publisher: European Respiratory Society (ERS)
Date: 04-06-2019
Publisher: Elsevier BV
Date: 06-2005
DOI: 10.1016/J.JHIN.2004.10.020
Abstract: The aim of this study was to assess the sensitivity and specificity of catheter-drawn and peripheral blood cultures. Paired blood culture s les collected over a 44-month period from a 280 bed Brisbane metropolitan hospital were analysed, using standard clinical and microbiological criteria, to determine whether blood culture isolates represented true bacteraemias or contamination. Catheter-collected cultures had a specificity of 85% compared with 97% for peripheral cultures. In only two instances (0.2%) was the diagnosis of clinically significant bacteraemia made on the basis of catheter culture alone. This study concluded that catheter-collected s les are not a good test for true bacteraemia, and that peripheral cultures are more reliable when the results of the paired cultures are discordant.
Publisher: AMPCo
Date: 08-05-2020
DOI: 10.5694/MJA2.50606
Publisher: Wiley
Date: 06-2015
DOI: 10.1111/JVH.72_12425
Publisher: BMJ
Date: 23-04-2021
DOI: 10.1136/THORAXJNL-2020-216794
Abstract: The heterogeneity in efficacy observed in studies of BCG vaccination is not fully explained by currently accepted hypotheses, such as latitudinal gradient in non-tuberculous mycobacteria exposure. We updated previous systematic reviews of the effectiveness of BCG vaccination to 31 December 2020. We employed an identical search strategy and inclusion/exclusion criteria to these earlier reviews, but reclassified several studies, developed an alternative classification system and considered study demography, diagnostic approach and tuberculosis (TB)-related epidemiological context. Of 21 included trials, those recruiting neonates and children aged under 5 were consistent in demonstrating considerable protection against TB for several years. Trials in high-burden settings with shorter follow-up also showed considerable protection, as did most trials in settings of declining burden with longer follow-up. However, the few trials performed in high-burden settings with longer follow-up showed no protection, sometimes with higher case rates in the vaccinated than the controls in the later follow-up period. The most plausible explanatory hypothesis for these results is that BCG protects against TB that results from exposure shortly after vaccination. However, we found no evidence of protection when exposure occurs later from vaccination, which would be of greater importance in trials in high-burden settings with longer follow-up. In settings of declining burden, most exposure occurs shortly following vaccination and the sustained protection observed for many years thereafter represents continued protection against this early exposure. By contrast, in settings of continued intense transmission, initial protection subsequently declines with repeated exposure to Mycobacterium tuberculosis or other pathogens.
Publisher: Elsevier BV
Date: 02-2020
Publisher: Elsevier BV
Date: 06-2009
Publisher: Elsevier BV
Date: 11-2018
DOI: 10.1016/J.JINF.2018.07.007
Abstract: Mental health disorders, social stress, and poor health-related quality of life are commonly reported among people with tuberculosis (TB). We conducted a systematic review and meta-analysis to quantify mental health disorders, social stressors, and health-related quality of life in patients with multidrug-resistant tuberculosis (MDR-TB). We searched PubMed, SCOPUS, ProQuest, Web of Science, and PsycINFO databases for studies that reported data on mental health disorders, social stressors, and health-related quality of life among MDR-TB patients. Hand-searching the reference lists of included studies was also performed. Studies were selected according to pre-defined selection criteria and data were extracted by two authors. Pooled prevalence and weighted mean difference estimates were performed using random-effects meta-analysis. Heterogeneity was explored using meta-regression, and subgroup analyses were performed. We included a total of 40 studies that were conducted in 20 countries. Depression, anxiety, and psychosis were the most common mental health disorders reported in the studies. The overall pooled prevalence was 25% (95% confidence interval (CI): 14, 39) for depression, 24% (95% CI: 2, 57) for anxiety, and 10% (95% CI: 7, 14) for psychosis. There was substantial heterogeneity in the estimates. The stratified analysis showed that the prevalence of psychosis was 4% (95% CI: 0, 22) before MDR-TB treatment commencement, and 9% (95% CI: 5, 13) after MDR-TB treatment commencement. The most common social stressors reported were stigma, discrimination, isolation, and a lack of social support. Health-related quality of life was significantly lower among MDR-TB patients when compared to drug-susceptible TB patients (Q = 9.88, p = 0.01, I This review found that mental health and social functioning are compromised in a significant proportion of MDR-TB patients, a finding confirmed by the poor health-related quality of life reported. Thus, there is a substantial need for integrating mental health services, social protection and social support into the clinical and programmatic management of MDR-TB.
Publisher: International Union Against Tuberculosis and Lung Disease
Date: 2017
Publisher: The Royal Society
Date: 13-03-2007
Abstract: Background . Antibiotic-resistant nosocomial pathogens can arise in epidemic clusters or sporadically. Genotyping is commonly used to distinguish epidemic from sporadic vancomycin-resistant enterococci (VRE). We compare this to a statistical method to determine the transmission characteristics of VRE. Methods and findings . A structured continuous-time hidden Markov model (HMM) was developed. The hidden states were the number of VRE-colonized patients (both detected and undetected). The input for this study was weekly point-prevalence data 157 weeks of VRE prevalence. We estimated two parameters: one to quantify the cross-transmission of VRE and the other to quantify the level of VRE colonization from sporadic sources. We compared the results to those obtained by concomitant genotyping and phenotyping. We estimated that 89% of transmissions were due to ward cross-transmission while 11% were sporadic. Genotyping found that 90% had identical glycopeptide resistance genes and 84% were identical or nearly identical on pulsed-field gel electrophoresis (PFGE). There was some evidence, based on model selection criteria, that the cross-transmission parameter changed throughout the study period. The model that allowed for a change in transmission just prior to the outbreak and again at the peak of the outbreak was superior to other models. This model estimated that cross-transmission increased at week 120 and declined after week 135, coinciding with environmental decontamination. Significance . We found that HMMs can be applied to serial prevalence data to estimate the characteristics of acquisition of nosocomial pathogens and distinguish between epidemic and sporadic acquisition. This model was able to estimate transmission parameters despite imperfect detection of the organism. The results of this model were validated against PFGE and glycopeptide resistance genotype data and produced very similar results. Additionally, HMMs can provide information about unobserved events such as undetected colonization.
Publisher: Informa UK Limited
Date: 2021
DOI: 10.2147/RMHP.S278774
Publisher: Elsevier BV
Date: 2019
DOI: 10.1016/J.TUBE.2018.08.011
Abstract: Accurate and timely diagnosis of tuberculosis (TB) is essential to control the global pandemic. Currently available immunodiagnostic tests cannot discriminate between latent tuberculosis infection (LTBI) and active tuberculosis. This study aimed to determine whether candidate mycobacterial antigen-stimulated cytokine biomarkers can discriminate between TB-uninfected and TB-infected adults, and additionally between LTBI and active TB disease. 193 adults were recruited, and categorised into four unambiguous diagnostic groups: microbiologically-proven active TB, LTBI, sick controls (non-TB lower respiratory tract infections) and healthy controls. Whole blood assays were used to determine mycobacterial antigen (CFP-10, ESAT-6, PPD)-stimulated cytokine (IL-1ra, IL-2, IL-10, IL-13, TNF-α, IFN-γ, IP-10 and MIP-1β) responses, measured by Luminex multiplex immunoassay. The background-corrected mycobacterial antigen-stimulated cytokine responses of all eight cytokines were significantly higher in TB-infected participants compared with TB-uninfected in iduals, with IL-2 showing the best performance characteristics. In addition, mycobacterial antigen-stimulated responses with IL-1ra, IL-10 and TNF-α were higher in participants with active TB compared those with LTBI, reaching statistical significance with PPD stimulation, although there was a degree of overlap between the two groups. Mycobacterial antigen-stimulated cytokine responses may prove useful in future immunodiagnostic tests to discriminate between tuberculosis-infected and tuberculosis-uninfected in idual, and potentially between LTBI and active tuberculosis.
Publisher: Informa UK Limited
Date: 14-05-2019
Publisher: Oxford University Press (OUP)
Date: 15-08-2008
DOI: 10.1086/590006
Publisher: Oxford University Press (OUP)
Date: 04-08-2014
DOI: 10.1093/CID/CIU602
Abstract: Increased global access and use of antiretroviral therapy (ART) for human immunodeficiency virus (HIV) has been postulated to undermine HIV prevention efforts by changing in idual risk-taking behavior. This review aims to determine whether ART use is associated with changes in sexual or injecting risk-taking behavior or diagnosis of sexually transmitted infections (STIs). A systematic review and meta-analysis was conducted of HIV-seropositive participants receiving ART compared with no ART use in experimental or observational studies. Primary outcomes included (1) any unprotected sexual intercourse, (2) STI diagnoses, and (3) any unsafe injecting behavior. Fifty-eight studies met the selection criteria. Fifty-six studies containing 32 857 participants reported unprotected sex 11 studies containing 16 138 participants reported STI diagnoses and 4 studies containing 1600 participants reported unsafe injecting behavior. All included studies were observational. Unprotected sex was lower in participants receiving ART than in those not receiving ART (odds ratio [OR], 0.73 95% confidence interval [CI], .64-.83 P < .001 heterogeneity I(2) = 79%) in both high-income (n = 38) and low-/middle-income country (n = 18) settings, without any evidence of publication bias. STI diagnoses were also lower among in iduals on ART (OR, 0.58 95% CI, .33-1.01 P = .053 I(2) = 92%) however, there was no difference in injecting risk-taking behavior with antiretroviral use (OR, 0.90 95% CI, .60-1.35 P = .6 I(2) = 0%). Despite concerns that use of ART might increase sexual or injecting risk-taking, available research suggests that unprotected sex is reduced among HIV-infected in iduals on treatment. The reasons for this are not yet clear, although self-selection and mutually reinforcing effects of HIV treatment and prevention messages among people on ART are likely.
Publisher: MDPI AG
Date: 24-04-2019
DOI: 10.3390/TROPICALMED4020071
Abstract: The tuberculosis (TB) health burden in Fiji has been declining in recent years, although challenges remain in improving control of the diabetes co-epidemic and achieving adequate case detection across the widely dispersed archipelago. We applied a mathematical model of TB transmission to the TB epidemic in Fiji that captured the historical reality over several decades, including age stratification, diabetes, varying disease manifestations, and incorrect diagnoses. Next, we simulated six intervention scenarios that are under consideration by the Fiji National Tuberculosis Program. Our findings show that the interventions were able to achieve only modest improvements in disease burden, with awareness raising being the most effective intervention to reduce TB incidence, and treatment support yielding the highest impact on mortality. These improvements would fall far short of the ambitious targets that have been set by the country, and could easily be derailed by moderate increases in the diabetes burden. Furthermore, the effectiveness of the interventions was limited by the extensive pool of latent TB infection, because the programs were directed at only active cases, and thus were unlikely to achieve the desired reductions in burden. Therefore, it is essential to address the co-epidemic of diabetes and treat people with latent TB infection.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 08-2015
Publisher: Centers for Disease Control and Prevention (CDC)
Date: 03-2019
Publisher: Elsevier BV
Date: 11-2010
DOI: 10.1016/J.DIAGMICROBIO.2010.07.022
Abstract: The interpretation of a positive result for Mycobacterium tuberculosis by nucleic acid lification such as polymerase chain reaction (PCR) can be challenging. We present 2 cases that illustrate the limitations of tuberculosis PCR on respiratory secretions in previously treated patients, even years after the previous disease episode.
Publisher: Mary Ann Liebert Inc
Date: 02-2007
DOI: 10.1089/SUR.2006.093
Publisher: Cambridge University Press (CUP)
Date: 12-2014
DOI: 10.1086/678596
Abstract: Multidrug-resistant bacteria are major causes of nosocomial infections and are associated with considerable morbidity, mortality, and healthcare costs. Preventive strategies have therefore become increasingly important. Mathematical modeling has been widely used to understand the transmission dynamics of nosocomial infections and the quantitative effects of infection control measures. This review will explore the principles of mathematical modeling used in nosocomial infections and discuss the effectiveness of infection control measures investigated using mathematical modeling. Infect Control Hosp Epidemiol 2014 (12):1521–1530
Publisher: Elsevier BV
Date: 04-2013
Publisher: Elsevier BV
Date: 05-2018
DOI: 10.1016/J.VACCINE.2018.04.046
Abstract: Motivated by the unexplained variation in the performance of some vaccines across different settings, we extend previous theoretical work to consider the potential impact of incomplete case ascertainment on measures of vaccine efficacy (VE), which is more likely in subclinical or clinically unimportant infections, such as rotavirus gastroenteritis. By simulating the measurement of VE under outbreak conditions using a discrete time stochastic SIR model, we compare three commonly used measures, VE Under plausibly low levels of ascertainment, the group with the most infections, and therefore the most missed cases, has the most falsely inflated denominator, producing similar rates in the control and intervention groups. As a result, VE This study demonstrates that a biologically active vaccine may produce a low measured VE under a range of epidemiological, vaccine-related and logistical conditions. Low case ascertainment may partly explain the observed heterogeneity in the performance of rotavirus vaccine across different settings, and should be considered in the design and interpretation of future field trials.
Publisher: American Society for Microbiology
Date: 04-2015
DOI: 10.1128/JCM.03239-14
Abstract: Colonization with Candida species is an independent risk factor for invasive candidiasis (IC), but the minimum and most practicable parameters for prediction of IC have not been optimized. We evaluated Candida colonization in a prospective cohort of 6,015 nonneutropenic, critically ill patients. Throat, perineum, and urine were s led 72 h post-intensive care unit (ICU) admission and twice weekly until discharge or death. Specimens were cultured onto chromogenic agar, and a subset underwent molecular characterization. Sixty-three (86%) patients who developed IC were colonized prior to infection 61 (97%) tested positive within the first two time points. The median time from colonization to IC was 7 days (range, 0 to 35). Colonization at any site was predictive of IC, with the risk of infection highest for urine colonization (relative risk [RR] = 2.25) but with the sensitivity highest (98%) for throat and/or perineum colonization. Colonization of ≥2 sites and heavy colonization of ≥1 site were significant independent risk factors for IC (RR = 2.25 and RR = 3.7, respectively), increasing specificity to 71% to 74% but decreasing sensitivity to 48% to 58%. Molecular testing would have prompted a resistance-driven decision to switch from fluconazole treatment in only 11% of patients infected with C. glabrata , based upon species-level identification alone. Positive predictive values (PPVs) were low (2% to 4%) and negative predictive values (NPVs) high (99% to 100%) regardless of which parameters were applied. In the Australian ICU setting, culture of throat and perineum within the first two time points after ICU admission captures 84% (61/73 patients) of subsequent IC cases. These optimized parameters, in combination with clinical risk factors, should strengthen development of a setting-specific risk-predictive model for IC.
Publisher: Cold Spring Harbor Laboratory
Date: 22-03-2022
DOI: 10.1101/2022.03.22.22272751
Abstract: Drug-resistant tuberculosis (DR-TB) is an ongoing challenge in the Torres Strait Islands (TSI) / Papua New Guinea (PNG) border region. Treatment success rates have historically been poor for patients diagnosed with DR-TB, leading to increased transmission. This study aimed to identify variables associated with unfavourable outcome in patients diagnosed with DR-TB to inform programmatic improvements. A retrospective study of all DR-TB cases who presented to Australian health facilities in the Torres Strait between 1 March 2000 and 31 March 2020 was performed. This time period covers four distinct TB programmatic approaches which reflect Australian and Queensland Government decisions on TB management in this remote region. Univariate and multivariate predictors of unfavourable outcome were analysed. Unfavourable outcome was defined as lost to follow up, treatment failure and death. Successful outcome was defined as cure and treatment completion. In total, 133 patients with resistance to at least one TB drug were identified. The vast majority (123/133 92%) of DR-TB patients had pulmonary involvement and of these, 41% (50/123) had both pulmonary and extrapulmonary TB. Unfavourable outcomes were observed in 29% (39/133) of patients. Patients living with human immunodeficiency virus, renal disease or diabetes (4/133 4/133 3/133) had an increased frequency of unfavourable outcome ( p .05), but the numbers were small. Among all 133 DR-TB patients, 41% had a low lymphocyte count, which was significantly associated with unfavourable outcome ( p .05). We noted a 50% increase in successful outcomes achieved in the 2016 - 2020 programmatic period, compared to earlier periods (OR 5.3, 95% Confidence Interval [1.3, 20.4]). Being a close contact of a known TB case was associated with improved outcome. While DR-TB treatment outcomes have improved over time, enhanced surveillance for DR-TB, better cross border collaboration and consistent diagnosis and management of comorbidities and other risk factors should further improve patient care and outcomes.
Publisher: Cold Spring Harbor Laboratory
Date: 14-01-2022
DOI: 10.1101/2022.01.13.22269264
Abstract: Tuberculosis (TB) remains a disease of public health significance at the Australia / Papua New Guinea (PNG) international border. In the remote Torres Strait Islands, aeromedical evacuation is a necessary but costly component of TB management and patients with critical care needs require support to prevent onward TB transmission. A detailed costing of an exemplar TB patient from PNG who presented to a Queensland Health facility in the Torres Strait and required urgent aeromedical evacuation was performed. Data were drawn from patient charts, financial and clinical information systems used within Queensland Health and the Torres and Cape Hospital and Health Service. The total cost of aeromedical evacuation was AUD 124,280 54% of the cost was attributed to travel. Between 2016 and 2019, 19 patients diagnosed with TB were medically evacuated from an outer Torres Strait Island with a median length of hospital stay of 57 days. Aeromedical evacuation and medical management costs require adequate budget allocation.
Publisher: Springer Science and Business Media LLC
Date: 02-12-2022
DOI: 10.1038/S41598-022-25242-X
Abstract: Wolbachia intracellular bacteria successfully reduce the transmissibility of arthropod-borne viruses (arboviruses) when introduced into virus-carrying vectors such as mosquitoes. Despite the progress made by introducing Wolbachia bacteria into the Aedes aegypti wild-type population to control arboviral infections, reports suggest that heat-induced loss-of- Wolbachia -infection as a result of climate change may reverse these gains. Novel, supplemental Wolbachia strains that are more resilient to increased temperatures may circumvent these concerns, and could potentially act synergistically with existing variants. In this article, we model the ecological dynamics among three distinct mosquito (sub)populations: a wild-type population free of any Wolbachia infection an invading population infected with a particular Wolbachia strain and a second invading population infected with a distinct Wolbachia strain from that of the first invader. We explore how the range of possible characteristics of each Wolbachia strain impacts mosquito prevalence. Further, we analyse the differential system governing the mosquito populations and the Wolbachia infection dynamics by computing the full set of basic and invasive reproduction numbers and use these to establish stability of identified equilibria. Our results show that releasing mosquitoes with two different strains of Wolbachia did not increase their prevalence, compared with a single-strain Wolbachia -infected mosquito introduction and only delayed Wolbachia dominance.
Publisher: Elsevier BV
Date: 10-2015
DOI: 10.1016/J.DRUGPO.2015.05.006
Abstract: The hepatitis C virus (HCV) epidemic is a major health issue in most developed countries it is driven by people who inject drugs (PWID). Injecting networks powerfully influence HCV transmission. In this paper we provide an overview of 10 years of research into injecting networks and HCV, culminating in a network-based approach to provision of direct-acting antiviral therapy. Between 2005 and 2010 we followed a cohort of 413 PWID, measuring HCV incidence, prevalence and injecting risk, including network-related factors. We developed an in idual-based HCV transmission model, using it to simulate the spread of HCV through the empirical social network of PWID. In addition, we created an empirically grounded network model of injecting relationships using exponential random graph models (ERGMs), allowing simulation of realistic networks for investigating HCV treatment and intervention strategies. Our empirical work and modelling underpins the TAP Study, which is examining the feasibility of community-based treatment of PWID with DAAs. We observed incidence rates of HCV primary infection and reinfection of 12.8 per 100 person-years (PY) (95%CI: 7.7-20.0) and 28.8 per 100 PY (95%CI: 15.0-55.4), respectively, and determined that HCV transmission clusters correlated with reported injecting relationships. Transmission modelling showed that the empirical network provided some protective effect, slowing HCV transmission compared to a fully connected, homogenous PWID population. Our ERGMs revealed that treating PWID and all their contacts was the most effective strategy and targeting treatment to infected PWID with the most contacts the least effective. Networks-based approaches greatly increase understanding of HCV transmission and will inform the implementation of treatment as prevention using DAAs.
Publisher: Springer Science and Business Media LLC
Date: 03-09-2019
DOI: 10.1038/S41598-019-49135-8
Abstract: Tuberculosis (TB) is a potentially fatal infectious disease that continues to be a public health problem in Bangladesh. Each year in Bangladesh an estimated 70,000 people die of TB and 300,000 new cases are projected. It is important to understand the association between TB incidence and weather factors in Bangladesh in order to develop proper intervention programs. In this study, we examine the delayed effect of weather variables on TB occurrence and estimate the burden of the disease that can be attributed to weather factors. We used generalized linear Poisson regression models to investigate the association between weather factors and TB cases reported to the Bangladesh National TB control program between 2007 and 2012 in three known endemic districts of North-East Bangladesh. The associated risk of TB in the three districts increases with prolonged exposure to temperature and rainfall, and persisted at lag periods beyond 6 quarters. The association between humidity and TB is strong and immediate at low humidity, but the risk decreases with increasing lag. Using the optimum weather values corresponding to the lowest risk of infection, the risk of TB is highest at low temperature, low humidity and low rainfall. Measures of the risk attributable to weather variables revealed that weather-TB cases attributed to humidity is higher than that of temperature and rainfall in each of the three districts. Our results highlight the high linearity of temporal lagged effects and magnitudes of the burden attributable to temperature, humidity, and rainfall on TB endemics. The results can hopefully advise the Bangladesh National TB control program and act as a practical reference for the early warning of TB cases.
Publisher: Elsevier BV
Date: 08-2012
Publisher: Elsevier BV
Date: 03-2021
Publisher: Informa UK Limited
Date: 07-2010
DOI: 10.2147/IDR.S8994
Publisher: Research Square Platform LLC
Date: 04-10-2022
DOI: 10.21203/RS.3.RS-2108937/V1
Abstract: Wolbachia intracellular bacteria successfully reduce the transmissibility of arthropod-borne viruses (arboviruses) when introduced into virus-carrying vectors such as mosquitoes. Despite the progress made by introducing Wolbachia bacteria into the Aedes aegypti wild-type population to control arboviral infections, reports suggest that heat-induced loss-of-Wolbachia infection as a result of climate change may reverse these gains. Novel, supplemental Wolbachia strains that are more resilient to increased temperatures may circumvent these concerns, and could potentially act synergistically with existing variants. In this article, we model the ecological dynamics among three distinct mosquito (sub)populations: a wild-type population free of any Wolbachia infection an invading population infected with a particular Wolbachia strain and a second invading population infected with a distinct Wolbachia strain from that of the first invader. We explore how the range of possible characteristics of each Wolbachia strain impacts mosquito prevalence. Further, we analyse the differential system governing the mosquito populations and the Wolbachia infection dynamics by computing the full set of basic and invasive reproduction numbers and use these to establish stability of identified equilibria. Our results show that releasing mosquitoes with two different strains of Wolbachia did not increase their prevalence, compared with a single-strain Wolbachia-infected mosquito introduction and only delayed Wolbachia dominance.
Publisher: Cambridge University Press (CUP)
Date: 08-2013
DOI: 10.1086/671273
Abstract: To determine the relationship between methicillin-resistant Staphylococcus aureus (MRSA) colonization density, colonization site, and probability of infection in a frequently screened cohort of intensive care unit (ICU) patients. Patients had swab s les tested for MRSA at admission to the ICU, discharge from the ICU, and twice weekly during their ICU stay, and they were followed up for development of MRSA infection. Swab test results were analyzed to determine the proportion of patients colonized and the proportion colonized at each screening site. Hazard of MRSA infection (rate of infection per day at risk) was calculated using a Cox proportional hazards analysis, and risk factors for MRSA infection, including presence of MRSA, degree of colonization, and pattern of colonization were determined. Among the 4,194 patient episodes, 238 (5.7%) had screening results that were positive for MRSA, and there were 34 cases of MRSA infection. The hazard ratio (HR) for developing an infection increased as more sites were colonized (HR, 3.4 for being colonized at more than 1 site compared with colonization at 1 site [95% confidence interval, 1.2-9.9]). Colonization site was predictive of developing infection (HR for nose or throat colonization compared with no colonization, 168 [95% confidence interval, 69-407]). This study demonstrated that the hazard of developing an infection was higher when more sites were colonized and that certain sites were more predictive of infection than others. These results may be useful for predicting infection in ICU patients and may influence treatment.
Publisher: Oxford University Press (OUP)
Date: 10-03-2017
DOI: 10.1093/AJE/KWW239
Abstract: New combination human acquired deficiency (HIV) prevention strategies that include biomedical and primary prevention approaches add complexity to the task of measuring sexual risk. Latent transition models are beneficial for understanding complex phenomena therefore, we trialed the application of latent class and latent transition models to HIV surveillance data. Our aims were to identify sexual risk states and model in iduals' transitions between states. A total of 4,685 HIV-negative men who have sex with men (MSM) completed behavioral questionnaires alongside tests for HIV and sexually transmissible infections at one of 2 Melbourne, Victoria, Australia, general practices (2007-2013). We found 4 distinct classes of sexual risk, which we labeled "monogamous" (n = 1,224), "risk minimizer" (n = 1,443), "risk potential" (n = 1,335), and "risk taker" (n = 683). A positive syphilis, gonorrhea, or chlamydia test was significantly associated with class membership. Among a subset of 516 MSM who had at least 3 clinic visits, there was general stability across risk classes MSM had on average a 0.70 (i.e., 70%) probability of remaining in the same class between visits 1 and 2 and between visits 2 and 3. Monogamous MSM were one exception the probability of remaining in the monogamous class was 0.51 between visits 1 and 2. Latent transition analyses identified unobserved risk patterns in surveillance data, characterized high-risk MSM, and quantified transitions over time.
Publisher: Elsevier BV
Date: 12-2008
Publisher: Oxford University Press (OUP)
Date: 10-03-2017
DOI: 10.1093/AJE/KWW238
Publisher: Public Library of Science (PLoS)
Date: 28-11-2017
Publisher: AMPCo
Date: 03-2012
DOI: 10.5694/MJA12.10082
Abstract: To determine incidence and trends in antibiotic resistance in Australian Salmonella enterica subspecies enterica serovars Typhi (S. Typhi) and Paratyphi (S. Paratyphi) isolates over the past 26 years. A retrospective analysis of consecutive microbiologically confirmed enteric fever isolates. All S. Typhi and S. Paratyphi isolates from patients diagnosed with enteric fever in Australia between 1985 and 2010. Incidence and variation in antibiotic resistance over time and according to country of origin. We analysed 2551 isolates, which originated from 74 countries or regions, mainly India (33%) and Indonesia (22%). The incidence among Australian residents increased from four to five before 2003 to seven cases per million person-years after 2003. Multidrug resistance (chlor henicol, icillin, trimethoprim) and nalidixic acid resistance emerged rapidly from the early 1990s, with nalidixic acid resistance increasing to 70% in 2009-2010, while multidrug resistance was relatively stable at between 4% and 11%. Nalidixic acid and multidrug resistance rates are highest in isolates from the Indian subcontinent. Some countries in South-East Asia, such as Indonesia, had very low rates of resistance however, this varied across the region. Nalidixic acid resistance has become widespread in enteric fever isolates from the Indian subcontinent and some parts of South-East Asia, justifying the use of ceftriaxone or azithromycin rather than ciprofloxacin as first-line treatment. However, resistance in some countries remains rare, potentially allowing treatment to be adjusted according to country of origin.
Publisher: Public Library of Science (PLoS)
Date: 26-02-2013
Publisher: Elsevier BV
Date: 2016
Publisher: Oxford University Press (OUP)
Date: 22-03-2022
DOI: 10.1093/IJE/DYAC045
Abstract: Ambitious population-based screening programmes for latent and active tuberculosis (TB) were implemented in the Republic of the Marshall Islands in 2017 and 2018. We used a transmission dynamic model of TB informed by local data to capture the Marshall Islands epidemic’s historical dynamics. We then used the model to project the future epidemic trajectory following the active screening interventions, as well as considering a counterfactual scenario with no intervention. We also simulated future scenarios including periodic interventions similar to those previously implemented, to assess their ability to reach the End TB Strategy targets and TB pre-elimination in the Marshall Islands. The screening activities conducted in 2017 and 2018 were estimated to have reduced TB incidence and mortality by around one-third in 2020, and are predicted to achieve the End TB Strategy milestone of 50% incidence reduction by 2025 compared with 2015. Screening interventions had a considerably greater impact when latent TB screening and treatment were included, compared with active case finding alone. Such combined programmes implemented at the national level could achieve TB pre-elimination around 2040 if repeated every 2 years. Our model suggests that it would be possible to achieve TB pre-elimination by 2040 in the Marshall Islands through frequent repetition of the same interventions as those already implemented in the country. It also highlights the importance of including latent infection testing in active screening activities.
Publisher: Springer Science and Business Media LLC
Date: 25-03-2021
DOI: 10.1038/S41598-021-86301-3
Abstract: Acute respiratory infections appear to precipitate vascular events. Acute myocardial infarction (AMI) and stroke are the leading cause of death and disability globally. This study was based on a cohort of patients admitted to Townsville University Hospital between January 2006 and December 2016. Using a self-controlled case series design, we investigated the risk of AMI or ischaemic stroke after an episode of pneumonia. We defined the ‘risk interval’ as the first 14 days after hospitalisation for pneumonia and the ‘control interval’ as one year before and one year after the risk interval. Among a population (N = 4557) with a median age of over 70, a total of 128 AMI and 27 stroke cases were identified within 1 year of an episode of pneumonia in this study. Ten and two admissions occurred during the risk interval, while 118 and 25 admissions occurred during the control period. The relative incidence ratios (RIR) of AMI increased after an episode of pneumonia (RIR=4.85, 95% confidence interval (CI) 2.44–9.67). The risk for stroke after the exposure period of 14 days was 4.94 (95% CI 1.12–21.78) considering only the first stroke incidence. The RIR results for AMI and stroke were not altered by adjusting for age, sex or Indigenous status. The risk of AMI and stroke were significantly higher two weeks after an episode of pneumonia.
Publisher: Cold Spring Harbor Laboratory
Date: 30-04-2021
DOI: 10.1101/2021.04.30.442212
Abstract: Community-associated, methicillin-resistant Staphylococcus aureus (MRSA) lineages have emerged in many geographically distinct regions around the world during the past 30 years. Here, we apply consistent phylodynamic methods across multiple community-associated MRSA lineages to describe and contrast their patterns of emergence and dissemination. We generated whole genome sequencing data for the Australian sequence type (ST) 93-MRSA-IV from remote communities in Far North Queensland and Papua New Guinea, and the Bengal Bay ST772-MRSA-V clone from metropolitan communities in Pakistan. Increases in the effective reproduction number (R e ) and sustained transmission (R e 1) coincided with spread of progenitor methicillin-susceptible S. aureus (MSSA) in remote northern Australia, dissemination of the ST93-MRSA-IV geno-type into population centers on the Australian East Coast, and sub-sequent importation into the highlands of Papua New Guinea and Far North Queensland. Analysis of a ST772-MRSA-V cluster in Pakistan suggests that sustained transmission in the community following importation of resistant genotypes may be more common than previously thought. Applying the same phylodynamic methods to existing lineage datasets, we identified common signatures of epidemic growth in the emergence and epidemiological trajectory of community-associated S. aureus lineages from America, Asia, Australasia and Europe. Surges in R e were observed at the ergence of antibiotic resistant strains, coinciding with their establishment in regional population centers. Epidemic growth was also observed amongst drug-resistant MSSA clades in Africa and northern Australia. Our data suggest that the emergence of community-associated MRSA and MSSA lineages in the late 20th century was driven by a combination of antibiotic resistant genotypes and host epidemiology, leading to abrupt changes in lineage-wide transmission dynamics and sustained transmission in regional population centers.
Publisher: Oxford University Press (OUP)
Date: 30-08-2013
Publisher: Cold Spring Harbor Laboratory
Date: 08-08-2019
DOI: 10.1101/729426
Abstract: Tuberculosis (TB) natural history remains poorly characterised and new investigations are impossible as it would be unethical to follow up TB patients without treating them. Estimates of TB burden and mortality rely heavily on TB self-recovery and mortality rates, as around 40% of in iduals with TB are never detected, making their prognosis entirely dependent on the disease natural history. We considered the reports identified in a previous systematic review of studies from the prechemotherapy era, and extracted detailed data on mortality over time. We used a continuous-time Markov model in a Bayesian framework to estimate the rates of TB-induced mortality and self-cure. A hierarchical model was employed to allow estimates to vary by cohort. Inference was performed separately for smear-positive TB (SP-TB) and smear-negative TB (SN-TB). We included 41 cohorts of SP-TB patients and 19 cohorts of pulmonary SN-TB patients in the analysis. No data were available on extrapulmonary TB. The posterior median estimates of the TB-specific mortality rates were 0.390 year −1 (0.329-0.452, 95% credible interval) and 0.025 year −1 (0.016-0.036) for SP-TB and SN-TB patients, respectively. The estimates for self-recovery rates were 0.233 year −1 (0.179-0.293) and 0.147 year −1 (0.087-0.248) for SP-TB and SN-TB patients, respectively. These rates correspond to average durations of untreated TB of 1.57 years (1.37-1.81) and 5.35 years (3.42-8.23) for SP-TB and SN-TB, respectively, when assuming a natural mortality rate of 0.014 year −1 (i.e. a 70-year life expectancy). TB-specific mortality rates are around 15 times higher for SP-TB than for SN-TB patients. This difference was underestimated dramatically in previous TB modelling studies that parameterised models based on the ratio of 3.3 between the 10-year case fatality of SP-TB and SN-TB. Our findings raise important concerns about the accuracy of past and current estimates of TB mortality and predicted impact of control interventions on TB mortality.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 24-12-2013
DOI: 10.1002/HEP.26623
Publisher: Springer Science and Business Media LLC
Date: 17-10-2020
DOI: 10.1186/S12936-020-03442-Y
Abstract: District Health Information Systems 2 (DHIS2) is used for supporting health information management in 67 countries, including Solomon Islands. However, there have been few published evaluations of the performance of DHIS2-enhanced disease reporting systems, in particular for monitoring infectious diseases such as malaria. The aim of this study was to evaluate DHIS2 supported malaria reporting in Solomon Islands and to develop recommendations for improving the system. The evaluation was conducted in three administrative areas of Solomon Islands: Honoria City Council, and Malaita and Guadalcanal Provinces. Records of nine malaria indicators including report submission date, total malaria cases, Plasmodium falciparum case record, Plasmodium vivax case record, clinical malaria, malaria diagnosed with microscopy, malaria diagnosed with (rapid diagnostic test) (RDT), record of drug stocks and records of RDT stocks from 1st January to 31st December 2016 were extracted from the DHIS2 database. The indicators permitted assessment in four core areas: availability, completeness, timeliness and reliability. To explore perceptions and point of view of the stakeholders on the performance of the malaria case reporting system, focus group discussions were conducted with health centre nurses, whilst in-depth interviews were conducted with stakeholder representatives from government (province and national) staff and World Health Organization officials who were users of DHIS2. Data were extracted from nine health centres in Honoria City Council and 64 health centres in Malaita Province. The completeness and timeliness from the two provinces of all nine indicators were 28.2% and 5.1%, respectively. The most reliable indicator in DHIS2 was ‘clinical malaria’ (i.e. numbers of clinically diagnosed malaria cases) with 62.4% reliability. Challenges to completeness were a lack of supervision, limited feedback, high workload, and a lack of training and refresher courses. Health centres located in geographically remote areas, a lack of regular transport, high workload and too many variables in the reporting forms led to delays in timely reporting. Reliability of reports was impacted by a lack of technical professionals such as statisticians and unavailability of tally sheets and reporting forms. The availability, completeness, timeliness and reliability of nine malaria indicators collected in DHIS2 were variable within the study area, but generally low. Continued onsite support, supervision, feedback and additional enhancements, such as electronic reporting will be required to further improve the malaria reporting system.
Location: Australia
Start Date: 2009
End Date: 2012
Funder: Australian Research Council
View Funded ActivityStart Date: 2012
End Date: 2016
Funder: National Health and Medical Research Council
View Funded ActivityStart Date: 2009
End Date: 2010
Funder: National Health and Medical Research Council
View Funded ActivityStart Date: 2022
End Date: 2026
Funder: National Health and Medical Research Council
View Funded ActivityStart Date: 2014
End Date: 2019
Funder: National Health and Medical Research Council
View Funded ActivityStart Date: 2013
End Date: 2017
Funder: National Health and Medical Research Council
View Funded ActivityStart Date: 2009
End Date: 2010
Funder: National Health and Medical Research Council
View Funded ActivityStart Date: 2009
End Date: 2010
Funder: National Health and Medical Research Council
View Funded ActivityStart Date: 2004
End Date: 2006
Funder: National Health and Medical Research Council
View Funded ActivityStart Date: 2007
End Date: 2009
Funder: National Health and Medical Research Council
View Funded ActivityStart Date: 2009
End Date: 2010
Funder: National Health and Medical Research Council
View Funded ActivityStart Date: 2006
End Date: 2007
Funder: National Health and Medical Research Council
View Funded ActivityStart Date: 2018
End Date: 2020
Funder: National Health and Medical Research Council
View Funded ActivityStart Date: 2018
End Date: 2020
Funder: National Health and Medical Research Council
View Funded ActivityStart Date: 2016
End Date: 2020
Funder: National Health and Medical Research Council
View Funded ActivityStart Date: 2009
End Date: 2012
Funder: Australian Research Council
View Funded ActivityStart Date: 2011
End Date: 2013
Funder: Australian Research Council
View Funded ActivityStart Date: 2014
End Date: 2019
Funder: National Health and Medical Research Council
View Funded ActivityStart Date: 2011
End Date: 2013
Funder: Australian Research Council
View Funded ActivityStart Date: Start date not available
End Date: End date not available
Funder: National Health and Medical Research Council
View Funded ActivityStart Date: 2009
End Date: 12-2012
Amount: $550,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 03-2011
End Date: 12-2014
Amount: $364,771.00
Funder: Australian Research Council
View Funded Activity