ORCID Profile
0000-0001-8134-5681
Current Organisations
University of Sheffield
,
University of Sydney
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Publisher: MDPI AG
Date: 11-07-2022
Abstract: Mycoplasma bovis (M. bovis) can cause a multitude of diseases in cattle, with detrimental effects on the farm economy and the welfare of both adult and young cattle. The objective of this study was to determine the prevalence of M. bovis in adult cows and calves in the south-west region of Western Australia. A cross-sectional study was conducted on 29 dairy farms with 699 apparently healthy adult lactating cows and 495 young calves during 2019–2020. Nasal swabs and blood s les collected from the animals and bulk tank milk (BTM) s les were assessed for M. bovis-specific proteins and antibodies by using polymerase chain reaction (PCR) and Mycoplasma immunogenic lipase A- Enzyme-Linked Immune Sorbent Assay (MilA ELISA). A seroprevalence of 42.5% (95% CI: 38.9–46.2) and 61% (95% CI: 56.6–65.2) was found in adult lactating cows and calves, respectively. The herd-level seroprevalence of M. bovis ranged from 4% (95% CI: 07–19.5) to 92% (95% CI: 75.0–97.8) in adult lactating cows and 25% (95% CI: 10.2–49.5) to 87% (95% CI: 67.9–95.5) for calves in these farms. None of the BTM and nasal swab s les were positive for M. bovis, indicating an absence of any current active infections on the farms. The female calves and pure Holstein–Friesian animals are twice as likely to be seropositive for M. bovis compared to male calves (OR 2.4 95% CI: 1.7–3.5) and Holstein–Friesian crossbred calves (OR 2.4 95% CI: 1.7–3.5). The high seroprevalence in both adult and young cattle in the southwest dairy farms of Western Australia warrants more effective farm biosecurity measures and further evaluation of the current prevention and management measures practiced on the farms.
Publisher: Elsevier BV
Date: 10-2021
Publisher: Copernicus GmbH
Date: 15-06-2023
DOI: 10.5194/AMT-2023-123
Abstract: Abstract. Laser Induced Fluorescence (LIF) spectroscopy has been widely applied to fieldwork measurements of OH radicals, and of HO2, following conversion to OH, over a wide variety of conditions, on different platforms, and in simulation chambers. Conventional calibration of HOx (OH + HO2) instruments has mainly relied on a single method, generating known concentrations of HOx from H2O vapour photolysis in a flow of zero air impinging just outside the s le inlet (SHOx = CHOx.[HOx], where SHOx is the observed signal and CHOx is the calibration factor). The FAGE (Fluorescence Assay by Gaseous Expansion) apparatus designed for HOx measurements in the Highly Instrumented Reactor for Atmospheric Chemistry (HIRAC) at the University of Leeds has been used to examine the sensitivity of FAGE to external gas temperatures (266 – 348 K). The conventional calibration methods give the temperature dependence of COH (relative to the value at 293 K) of (0.0059 ± 0.0015) K-1 and CHO2 of (0.014 ± 0.013) K-1. Errors are 2σ. COH was also determined by observing the decay of hydrocarbons (typically cyclohexane) caused by OH reactions giving COH (again, relative to the value at 293 K) of (0.0038 ± 0.0007) K-1. Additionally, CHO2 was determined based on the second order kinetics of HO2 recombination with the temperature dependence of CHO2, relative to 293 K being (0.0064 ± 0.0034) K-1. The temperature dependence of CHOx depends on HOx number density, quenching, relative population of the probed OH rotational level and HOx transmission from inlet to detection axis. The first three terms can be calculated and, in combination with the measured values of CHOx, show that HOx transmission increases with temperature. Comparisons with other instruments and the implications of this work are discussed.
Publisher: Public Library of Science (PLoS)
Date: 25-01-2019
Publisher: Public Library of Science (PLoS)
Date: 29-04-2019
Publisher: Elsevier BV
Date: 04-2021
Publisher: Frontiers Media SA
Date: 06-06-2019
Publisher: MDPI AG
Date: 25-10-2021
DOI: 10.3390/ANI11113047
Abstract: Non-typeable (NT) Staphylococcus aureus strains are associated with chronic bovine mastitis. This study investigates the impact of biofilm formation by clinical NT S. aureus on cytokine production and mammary tissue damage by using a mouse mastitis model. Mice infected with two different NT S. aureus strains with strong and weak biofilm forming potential demonstrated identical clinical symptoms (moderate), minimal inflammatory infiltrates, and tissue damage (level 1 histopathological changes) in the mammary glands. However, the S. aureus load in the mammary glands of mice and the level of pro-inflammatory cytokines (IL-1β, IL-6, IL-12, IL-17 and IFN-γ) in serum were significantly higher (p ≤ 0.05) in those infected with the strong biofilm forming NT S. aureus strain. The level of IL-6 in sera s les of these mice was extremely high (15,479.9 ± 532 Pg/mL). Furthermore, these mice died in 24h of post infection compared to 30 h in the weak biofilm forming NT S. aureus infected group. The study demonstrates no association between the strength of PIA (polysaccharide intercellular adhesion)-dependent biofilm production by clinical NT S. aureus and mammary gland pathology in a mouse mastitis model. However, the role of biofilm in the virulence of S. aureus advancing the time of mortality in mice warrants further investigation.
Publisher: Springer Science and Business Media LLC
Date: 22-09-2021
DOI: 10.1186/S44149-021-00023-7
Abstract: Rabies is an acute encephalitis caused by a lyssavirus . It is primarily transmitted through bites of infected dogs which results in the worldwide death of an estimated 59000 humans every year. The disease is preventable through the application of post-exposure prophylaxis (PEP) and its elimination has been demonstrated in many countries by applying multiple interventions simultaneously. Nonetheless, rabies is still widespread in many developing countries, primarily due to the poor implementation of intervention strategies that include inadequate dog-bite wound management practices, unavailability/unaffordability of PEP by the communities, failure to control the disease in free-roaming dogs and wildlife, improper dog population management, weak surveillance and diagnostic facilities and a lack of a One Health approach to the disease. In this review, strategies to control dog-mediated rabies through a One Health approach were discussed. We recommend applying multiple interventions against the disease by involving all the concerned stakeholders in selected urban and rural areas of the countries where rabies is endemic. An empirical demonstration of disease freedom in the selected areas through a One Health approach is needed to convince policymakers to invest in rabies prevention and control on the national level. This multifaceted One Health control model will enhance the likelihood of achieving the goal of global rabies eradication by 2030.
Publisher: Public Library of Science (PLoS)
Date: 16-11-2018
Publisher: Springer Science and Business Media LLC
Date: 12-11-2019
DOI: 10.1038/S41598-019-52992-Y
Abstract: An understanding of the core demographic characteristics of the sub-populations of FRD is essential to effectively implement both rabies control interventions through mass vaccination of FRD, and dog population control programmes. This study compares the data obtained following photographic sight-resight surveys in rural (Shirsuphal village in west India) and urban (Municipal Corporation Panchkula in north India) locations . A total of 263 and 1408 FRD were seen at least once through 617 and 3465 sightings in the rural and urban sites, respectively. The rural location had a lower proportion of females (OR 0.5, 95% CI 0.4–0.7) and a higher proportion of poor and fair conditioned dogs (OR 1.8, 95% CI 1.3–2.3) compared to the urban setting. The rural site also had fewer active FRD (OR 0.6, 95% CI 0.5–0.7) and FRD were less likely to be sighted within 20 m of garbage points (OR 0.3, 95% CI 0.2–0.3) compared to the urban site. The demographic composition of the FRD population was found to vary within the urban location, with the odds of sighting a de-sexed dog being significantly higher in residential areas compared to other areas. The study underlines the importance of knowing the demographic composition of FRD for implementation of effective interventions against rabies. Fewer female dogs in the rural location indicate that spaying could be an effective tool for dog population management in this setting, while presence of dogs within 20 m of garbage points in urban settings highlights that an improved garbage management may reduce the carrying capacity of the urban locality resulting in smaller FRD population. It is concluded that quick and low cost surveys can generate useful demographic data for FRD in urban and rural settings which can be useful to understand the epidemiology of rabies and its control.
Publisher: MDPI AG
Date: 08-12-2020
DOI: 10.3390/ANI10122332
Abstract: The dairy industry plays an important role in the economy and food security of India. A study of the dairy value chains was conducted in Punjab, India, to identify production constraints and biosecurity risks. Focus group discussions and key informant interviews were conducted during 2018–2019 with a total of 119 participants comprising veterinarians (41), paraveterinarians (15), veterinary academics (12), dairy farmers (46) and key informants (5). Input and output value chains were created, and potential risk nodes were identified that could facilitate the transmission of pathogens between animals, farms and villages. The majority of the participants were male (93%), middle-aged (68%) or worked in rural areas (75%). Most of the farmers self-cultivated their green fodder (82%), used the wheat straw from their own fields (60%) but purchased commercial feed (63%). Artificial insemination was used by 85% of farmers for cattle, but only 68% for buffaloes. Most of the farmers (76%) reported getting their animals vaccinated against foot-and-mouth disease and hemorrhagic septicemia. Animals were sold and purchased without any health certification and testing in most cases. Adoption of biosecurity measures by farmers and the use of personal protective equipment by veterinary personnel were very low. We recommend conducting epidemiological studies to further characterize the identified risk nodes, training of veterinary practitioners and farmers to ensure adequate biosecurity practices and the appropriate use of personal protective equipment.
Publisher: Frontiers Media SA
Date: 23-05-2018
Publisher: MDPI AG
Date: 30-09-2019
Abstract: Adequate vaccination coverage of free roaming dogs (FRD) against canine rabies is not achieved primarily due to difficulties in administering parenteral vaccinations to this population. One factor associated with this difficulty is the tendency of FRD to form groups, which increases their aggressive behavior, resulting in a significant risk of dog-bites for the vaccinators. This study investigated factors that influenced FRD forming groups and their home-ranges, using data obtained from photographic capture-recapture/sight-resight surveys conducted in rural Shirsuphal (584 sightings) and urban Panchkula (3208 sightings), India. In the rural site, older dogs (OR 0.5, 95% CI 0.2–0.9, p = 0.03) and FRD sighted within 20 m of garbage sites (OR 0.6, 95% CI 0.4–0.9, p = 0.02) were less likely to be in groups. The number of dogs sighted with an FRD decreased with increased resight-probability of that dog (β= –1.0, p 0.001). The rural FRD with smaller home-ranges were more likely to be sighted alone (OR 2.3, 95% CI 1.0–95, p = 0.04) than those with larger home-ranges. In the urban site, females (OR 1.3, 95% CI 1.1–1.5, p = 0.002) and older dogs (OR 1.5, 95% CI 1.1–2.1, p = 0.07) were more likely to be found in groups, and groups of dogs were more likely to be seen within 20 meters of garbage sites (OR 1.7, 95% CI 1.5–2.0, p 0.001). The distribution of urban FRD sighted alone, in pairs, triads, and in packs of ≥4 dogs were not random in the administrative (p = 0.02), and the two industrial (p = 0.03 & 0.01) survey tracks of the urban site, implying stable groups. The resighting probability of a dog (β = 0.3, p 0.0001) and presence of garbage within 20 m (β = 0.2, p 0.0001) in the urban site increased the likelihood of sighting a FRD with other dogs. It is concluded that data on the resighting probability, presence of garbage points, and home-ranges can be utilised to guide the selection of parenteral or oral rabies vaccination to achieve a population vaccination coverage of 70% to break the transmission cycle of rabies virus in FRD in India.
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: India
No related grants have been discovered for Thomas Speak.