ORCID Profile
0000-0001-7772-9148
Current Organisations
Murdoch University
,
Mahidol Oxford Tropical Medicine Research Unit
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Publisher: Springer Science and Business Media LLC
Date: 03-06-2013
Publisher: Elsevier BV
Date: 02-2007
DOI: 10.1016/J.VACCINE.2006.10.038
Abstract: Vaccines are urgently needed to elicit immunity to different influenza virus strains. DNA vaccines can elicit partial protective immunity, however their efficacy requires improvement. We assessed the capacity of in idual type I IFN multigene family members as subtype transgenes to abrogate influenza virus replication in a vaccination/challenge mouse model. Differences in antiviral efficacy were found among the subtypes with IFNA5 and IFNA6 being most effective, while IFNA1 was the least effective in reducing lung virus replication. Mice vaccinated with combinatorial HA/IFNA6 or NP/IFNA6 showed reduced lung viral titres, clinical score, body weight loss, and pulmonary tissue damage compared to IFNA6, HA, or NP viral vaccination alone. In addition, IFNA6 increased IgG2a titres with upregulation of IFN-gamma response in the respiratory tract. We conclude that IFN-alpha 6 has antiviral and immunomodulatory effects, which improve efficacy of DNA vaccines for enhanced control of influenza.
Publisher: American Society of Tropical Medicine and Hygiene
Date: 02-08-2017
Publisher: World Health Organization, Western Pacific Regional Office
Date: 05-12-2013
Publisher: Springer Science and Business Media LLC
Date: 29-05-2020
DOI: 10.1038/S41467-020-16670-2
Abstract: Understanding the particle size distribution in the air and patterns of environmental contamination of SARS-CoV-2 is essential for infection prevention policies. Here we screen surface and air s les from hospital rooms of COVID-19 patients for SARS-CoV-2 RNA. Environmental s ling is conducted in three airborne infection isolation rooms (AIIRs) in the ICU and 27 AIIRs in the general ward. 245 surface s les are collected. 56.7% of rooms have at least one environmental surface contaminated. High touch surface contamination is shown in ten (66.7%) out of 15 patients in the first week of illness, and three (20%) beyond the first week of illness ( p = 0.01, χ 2 test). Air s ling is performed in three of the 27 AIIRs in the general ward, and detects SARS-CoV-2 PCR-positive particles of sizes µm and 1–4 µm in two rooms, despite these rooms having 12 air changes per hour. This warrants further study of the airborne transmission potential of SARS-CoV-2.
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: Mary Ann Liebert Inc
Date: 08-2011
Abstract: Rickettsia felis causes flea-borne spotted fever in humans worldwide. The cat flea, Ctenocephalides felis, serves as vector and reservoir host for this disease agent. To determine the role of dogs as potential reservoir hosts for spotted fever group rickettsiae, we screened blood from 100 pound dogs in Southeast Queensland by using a highly sensitive genus-specific PCR. Nine of the pound dogs were positive for rickettsial DNA and subsequent molecular sequencing confirmed lification of R. felis. A high prevalence of R. felis in dogs in our study suggests that dogs may act as an important reservoir host for R. felis and as a potential source of human rickettsial infection.
Publisher: Centers for Disease Control and Prevention (CDC)
Date: 12-2019
Publisher: Springer Science and Business Media LLC
Date: 12-2019
DOI: 10.1186/S12879-019-4653-4
Abstract: Scrub typhus is an important arthropod-borne disease causing significant acute febrile illness by infection with Orientia spp . Using a risk-based approach, this review examines current practice, the evidence base and regulatory requirements regarding matters of biosafety and biosecurity, and presents the case for reclassification from Risk Group 3 to Risk Group 2 along with recommendations for safe working practices of risk-based activities during the manipulation of Orientia spp. in the laboratory. We recommend to reclassify Orientia spp. to Risk Group 2 based on the classification for RG2 pathogens as being moderate in idual risk, low community risk. We recommend that low risk activities, can be performed within a biological safety cabinet located in a Biosafety Level (BSL) 2 core laboratory using standard personal protective equipment. But when the risk assessment indicates, such as high concentration and volume, or aerosol generation, then a higher biocontainment level is warranted. For, the majority of animal activities involving Orientia spp., Animal BSL 2 (ABSL2) is recommended however where high risk activities are performed including necropsies, Animal BSL (ABSL3) is recommended.
Publisher: Elsevier BV
Date: 11-2010
DOI: 10.1016/J.VETMIC.2010.04.018
Abstract: A survey of ectoparasites on feral pigs identified two commonly occurring ixodid tick species Amblyomma triguttatum triguttatum and Ixodes australiensis. Molecular screening of A. t. triguttatum and I. australiensis for the presence of Rickettsia species detected the presence of rickettsiae belonging to the Spotted Fever Group (SFG) in 78.4% of screened A. t. triguttatum. None of the screened I. australiensis were positive for rickettsiae. Sequence analysis of the gltA and ompA loci of positive Rickettsia isolates were 100% homologous to the newly described species Rickettsia gravesii sp. nov. BWI-1. Serological screening of feral pigs detected antibodies to SFG Rickettsia in 50% of serum s les tested. These findings suggest that A. t. triguttatum is a vector/reservoir for R. gravesii sp. nov.
Publisher: American Society for Microbiology
Date: 10-2013
DOI: 10.1128/CMR.00032-13
Abstract: Tick-borne rickettsioses are caused by obligate intracellular bacteria belonging to the spotted fever group of the genus Rickettsia . These zoonoses are among the oldest known vector-borne diseases. However, in the past 25 years, the scope and importance of the recognized tick-associated rickettsial pathogens have increased dramatically, making this complex of diseases an ideal paradigm for the understanding of emerging and reemerging infections. Several species of tick-borne rickettsiae that were considered nonpathogenic for decades are now associated with human infections, and novel Rickettsia species of undetermined pathogenicity continue to be detected in or isolated from ticks around the world. This remarkable expansion of information has been driven largely by the use of molecular techniques that have facilitated the identification of novel and previously recognized rickettsiae in ticks. New approaches, such as swabbing of eschars to obtain material to be tested by PCR, have emerged in recent years and have played a role in describing emerging tick-borne rickettsioses. Here, we present the current knowledge on tick-borne rickettsiae and rickettsioses using a geographic approach toward the epidemiology of these diseases.
Publisher: Oxford University Press (OUP)
Date: 22-01-2020
DOI: 10.1093/CID/CIAA042
Abstract: In Melanesia, the prevalence of trachomatous inflammation–follicular (TF) suggests that public health–level interventions against active trachoma are needed. However, the prevalence of trachomatous trichiasis is below the threshold for elimination as a public health problem and evidence of conjunctival infection with trachoma’s causative organism (Chlamydia trachomatis [CT]) is rare. Here, we examine the prevalence of ocular infection with CT and previous exposure to CT in three evaluation units (EUs) of Papua New Guinea. All in iduals aged 1–9 years who were examined for clinical signs of trachoma in 3 Global Trachoma Mapping Project EUs were eligible to take part in this study (N = 3181). Conjunctival swabs were collected from 349 children with TF and tested by polymerase chain reaction to assess for ocular CT infection. Dried blood spots were collected from 2572 children and tested for anti-Pgp3 antibodies using a multiplex assay. The proportion of children with TF who had CT infection was low across all 3 EUs (overall 2%). Anti-Pgp3 seroprevalence was 5.2% overall and there was no association between anti-Pgp3 antibody level and presence of TF. In 2 EUs, age-specific seroprevalence did not increase significantly with increasing age in the 1- to 9-year-old population. In the third EU, there was a statistically significant change with age but the overall seroprevalence and peak age-specific seroprevalence was very low. Based on these results, together with similar findings from the Solomon Islands and Vanuatu, the use of TF to guide antibiotic mass drug administration decisions in Melanesia should be reviewed.
Publisher: World Health Organization, Western Pacific Regional Office
Date: 29-09-2017
Publisher: Springer Science and Business Media LLC
Date: 16-10-2020
DOI: 10.1038/S41467-020-19080-6
Abstract: SARS-CoV-2 is the novel coronavirus responsible for the current COVID-19 pandemic. Severe complications are observed only in a small proportion of infected patients but the cellular mechanisms underlying this progression are still unknown. Comprehensive flow cytometry of whole blood s les from 54 COVID-19 patients reveals a dramatic increase in the number of immature neutrophils. This increase strongly correlates with disease severity and is associated with elevated IL-6 and IP-10 levels, two key players in the cytokine storm. The most pronounced decrease in cell counts is observed for CD8 T-cells and VD2 γδ T-cells, which both exhibit increased differentiation and activation. ROC analysis reveals that the count ratio of immature neutrophils to VD2 (or CD8) T-cells predicts pneumonia onset (0.9071) as well as hypoxia onset (0.8908) with high sensitivity and specificity. It would thus be a useful prognostic marker for preventive patient management and improved healthcare resource management.
Publisher: Cold Spring Harbor Laboratory
Date: 12-06-2020
DOI: 10.1101/2020.06.11.147389
Abstract: SARS-CoV-2 is the novel coronavirus responsible for the current COVID-19 pandemic. Severe complications are observed only in a small proportion of infected patients but the cellular mechanisms underlying this progression are still unknown. Comprehensive flow cytometry of whole blood s les from 54 COVID-19 patients revealed a dramatic increase in the number of immature neutrophils. This increase strongly correlated with disease severity and was associated with elevated IL-6 and IP-10 levels, two key players in the cytokine storm. The most pronounced decrease in cell counts was observed for CD8 T-cells and VD2 γδ T-cells, which both exhibited increased differentiation and activation. ROC analysis revealed that the count ratio of immature neutrophils to CD8 or VD2 T-cells predicts pneumonia onset (0.9071) as well as hypoxia onset (0.8908) with high sensitivity and specificity. It would thus be a useful prognostic marker for preventive patient management and improved healthcare resource management.
Publisher: American Society of Tropical Medicine and Hygiene
Date: 03-09-2014
Publisher: Oxford University Press (OUP)
Date: 03-08-2020
DOI: 10.1093/OFID/OFAA335
Abstract: The performance of real-time reverse transcription polymerase chain reaction (rRT-PCR) for SARS-CoV-2 varies with s ling site(s), illness stage, and infection site. Unilateral nasopharyngeal, nasal midturbinate, throat swabs, and saliva were simultaneously s led for SARS-CoV-2 rRT-PCR from suspected or confirmed cases of COVID-19. True positives were defined as patients with at least 1 SARS-CoV-2 detected by rRT-PCR from any site on the evaluation day or at any time point thereafter, until discharge. Diagnostic performance was assessed and extrapolated for site combinations. We evaluated 105 patients 73 had active SARS-CoV-2 infection. Overall, nasopharyngeal specimens had the highest clinical sensitivity at 85%, followed by throat, 80%, midturbinate, 62%, and saliva, 38%–52%. Clinical sensitivity for nasopharyngeal, throat, midturbinate, and saliva was 95%, 88%, 72%, and 44%–56%, respectively, if taken ≤7 days from onset of illness, and 70%, 67%, 47%, 28%–44% if & days of illness. Comparing patients with upper respiratory tract infection (URTI) vs pneumonia, clinical sensitivity for nasopharyngeal, throat, midturbinate, and saliva was 92% vs 70%, 88% vs 61%, 70% vs 44%, 43%–54% vs 26%–45%, respectively. A combination of nasopharyngeal plus throat or midturbinate plus throat specimen afforded overall clinical sensitivities of 89%–92% this rose to 96% for persons with URTI and 98% for persons ≤7 days from illness onset. Nasopharyngeal specimens, followed by throat specimens, offer the highest clinical sensitivity for COVID-19 diagnosis in early illness. Clinical sensitivity improves and is similar when either midturbinate or nasopharyngeal specimens are combined with throat specimens. Upper respiratory specimens perform poorly if taken after the first week of illness or if there is pneumonia.
Publisher: World Health Organization, Western Pacific Regional Office
Date: 11-04-2012
Publisher: Springer Science and Business Media LLC
Date: 07-02-2017
Publisher: F1000 Research Ltd
Date: 10-03-2022
DOI: 10.12688/WELLCOMEOPENRES.16393.2
Abstract: In rural areas of South and Southeast Asia malaria is declining but febrile illnesses still account for substantial morbidity and mortality. Village health workers (VHWs) are often the first point of contact with the formal health system, and for patients with febrile illnesses they can provide early diagnosis and treatment of malaria. However, for the majority of febrile patients, VHWs lack the training, support and resources to provide further care. Consequently, treatable bacterial illnesses are missed, antibiotics are overused and poorly targeted, and patient attendance wanes along with declining malaria. This Open Letter announces the start of a new initiative, the Rural Febrile Illness (RFI) project, the first in a series of projects to be implemented as part of the South and Southeast Asian Community-based Trials Network (SEACTN) research programme. This multi-country, multi-site project will run in Bangladesh, Cambodia, Lao PDR, Thailand, and Myanmar. It will define the epidemiological baseline of febrile illness in nine remote and underserved areas of Asia where malaria endemicity is declining and access to health services is limited. The RFI project aims to determine the incidence, causes and outcomes of febrile illness understand the opportunities, barriers and appetite for adjustment of the role of VHWs to include management of non-malarial febrile illnesses and establish a network of community healthcare providers and facilities capable of implementing interventions designed to triage, diagnose and treat patients presenting with febrile illnesses within these communities in the future.
Publisher: BMJ
Date: 10-2020
DOI: 10.1136/BMJOPEN-2020-041784
Abstract: Our project follows community requests for health service incorporation into conservation collaborations in the rainforests of Papua New Guinea (PNG). This protocol is for health needs assessments, our first step in coplanning medical provision in communities with no existing health data. The study includes clinical assessments and rapid anthropological assessment procedures (RAP) exploring the health needs and perspectives of partner communities in two areas, conducted over 6 weeks fieldwork. First, in Wanang village (population c.200), which is set in lowland rainforest. Second, in six communities (population c.3000) along an altitudinal transect up the highest mountain in PNG, Mount Wilhelm. In idual primary care assessments incorporate physical examinations and questioning (providing qualitative and quantitative data) while RAP includes focus groups, interviews and field observations (providing qualitative data). Given absence of in-community primary care, treatments are offered alongside research activity but will not form part of the study. Data are collected by a research fellow, primary care clinician and two PNG research technicians. After quantitative and qualitative analyses, we will report: ethnoclassifications of disease, causes, symptoms and perceived appropriate treatment community rankings of disease importance and service needs attitudes regarding health service provision disease burdens and associations with altitudinal-related variables and cultural practices. To aid wider use study tools are in online supplemental file, and paper and ODK versions are available free from the corresponding author. Challenges include supporting informed consent in communities with low literacy and erse cultures, moral duties to provide treatment alongside research in medically underserved areas while minimising risks of therapeutic misconception and inappropriate inducement, and PNG research capacity building. Brighton and Sussex Medical School (UK), PNG Institute of Medical Research and PNG Medical Research Advisory Committee have approved the study. Dissemination will be via journals, village meetings and plain language summaries.
Publisher: Microbiology Society
Date: 09-2017
Abstract: A rickettsial organism harboured by Amblyomma triguttatum ticks on Barrow Island, Western Australia, was discovered after reports of possible rickettsiosis among local workers. Subsequent isolation of this rickettsia (strain BWI-1) in cell culture and analysis of its phylogenetic, genotypic and phenotypic relationships with type strains of Rickettsia species with standing in nomenclature suggested that it was sufficiently ergent to warrant its classification as a new species. Multiple gene comparison of strain BWI-1 revealed degrees of sequence similarity with Rickettsia raoultii, its closest relative, of 99.58, 98.89, 97.03, 96.93 and 95.73 % for the 16S rRNA, citrate synthase, ompA, ompB and sca4 genes, respectively. Serotyping in mice also demonstrated that strain BWI-1T was distinct from Rickettsia raoultii. Thus, we propose the naming of a new species, Rickettsia gravesii sp. nov., based on its novel genotypic and phenotypic characteristics. Strain BWI-1T was deposited in the ATCC, CSUR and ARRL collections under reference numbers VR-1664, CSUR R172 and RGBWI-1, respectively.
Publisher: Informa UK Limited
Date: 2021
Publisher: Informa UK Limited
Date: 2011
Publisher: American Society for Microbiology
Date: 26-12-2013
Abstract: Rickettsia gravesii is a new Rickettsia species closely related to the human pathogen Rickettsia massiliae . Here, we describe the genome sequence of R. gravesii strain BWI-1, isolated from Amblyomma triguttatum triguttatum ticks collected from humans on Barrow Island, Western Australia.
Publisher: American Society for Microbiology
Date: 08-2018
DOI: 10.1128/JCM.01728-17
Abstract: Rickettsioses are globally distributed and caused by the family Rickettsiaceae , which comprise a erse and expanding list of organisms. These include two genera, Rickettsia and Orientia .
Publisher: Centers for Disease Control and Prevention (CDC)
Date: 06-2014
No related grants have been discovered for Mohammad Yazid Abdad.