Comparison of three diagnostic methods to detect the occurrence of Fasciola species in communally grazed cattle in the North West Province, South Africa

DATA AVAILABILITY STATEMENT : The data presented in this study are available on request from the corresponding author.Fasciolosis causes significant economic losses in commercial cattle herds in South Africa, but its prevalence is unknown in most communal areas. A cross-sectional study was conducted with the aim of determining the occurrence of bovine fasciolosis using three different diagnostic methods in Moretele Local Municipality in Bojanala District, NorthWest Province. Faecal samples were collected from 277 cattle of different breeds, ages, sex and faecal condition scores and examined using the sedimentation technique, quantitative real-time polymerase chain reaction (qPCR) and faecal antigen enzyme-linked immunosorbent assay (coproELISA). All samples were negative for bovine fasciolosis using coproELISA. A total of 73 (26.4%) samples were positive using the qPCR, while 36 were positive using the sedimentation technique, with low faecal egg counts (1 to 20 eggs per gram). The qPCR detected the highest positivity (26.4%, 95% CI 21.3, 32.0) followed by the sedimentation test (13.0%; 95% CI 9.3, 17.5). Location, breed, sex, age and faecal consistency score were not associated with positive qPCR results (p > 0.05). There was also no significant agreement (kappa = 0.011, p = 0.843) between qPCR and the sedimentation technique for the detection of Fasciola spp. The qPCR appeared to be the most sensitive method for detection of Fasciola spp. Further studies are required on the characterisation of Fasciola spp. in communal cattle in South Africa.The National Research Foundation (NRF) of South Africa, the University of Pretoria (South Africa) postgraduate bursary and the University of Ibadan (Nigeria) Tertiary Education Trust Fund.https://www.mdpi.com/journal/pathogensam2023Production Animal StudiesVeterinary Tropical Disease

Effects of probiotic (Saccharomyces cerevisiae) and ascorbic acid on oxidative gene damage biomarker, heat shock protein 70 and interleukin 10 in broiler chickens exposed to heat stress

Heat stress is a prominent factor responsible for losses economically in poultry meat industry due to adverse effects on the general performance of broiler chickens. In this study, we evaluated the effects of probiotic (Saccharomyces cerevisiae) and ascorbic acid on oxidative gene damage biomarker, heat shock protein 70 (HSP70) and interleukin 10 (IL-10) in broiler chickens exposed to heat stress under natural conditions. Fifty-six broiler chickens served as the subjects, they were divided into 4 groups of 14 as follows: group I (control), group II (probiotic S. cerevisiae at 1 g/kg of feed), group III (ascorbic acid at 200 mg/kg of feed) and group IV (probiotic + ascorbic acid at 1 g/kg and 200 mg/kg of feed, respectively). The treatments were administered via feed for 35 days (D1 to D35). Enzyme-linked immunosorbent assay (ELISA) and one step real time reverse transcription polymerase chain reaction (RT-PCR) was utilised to study the effects of heat stress on the expression levels of 8-hydroxy-2′-deoxyguanosine (8-OHdG), HSP70 and IL-10 respectively, in broiler chickens raised during the hot summer season. The level of 8-OHdG gene was significantly lower in the probiotic administered group. The expression level of HSP70 was lowest in the ascorbic acid group while, IL-10 level of expression was highest in the probiotic + ascorbic acid group. The administered antioxidants were efficient in exhibiting anti-stress effects at the level of gene expression. We conclude that probiotic, ascorbic acid and probiotic + ascorbic acid reduced oxidative gene damage, affected the expression of HSP70 and increased the level of IL-10 gene respectively, in broiler chickens exposed to heat stressThe University of Pretoria Doctoral Research Bursary, Department of Anatomy and Physiology and Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, South Africa.https://www.sciencedirect.com/journal/animal-geneAnatomy and PhysiologyParaclinical SciencesVeterinary Tropical Disease

Immunological evidence of variation in exposure and immune response to Bacillus anthracis in herbivores of Kruger and Etosha national parks

Exposure and immunity to generalist pathogens differ among host species and vary across spatial scales. Anthrax, caused by a multi-host bacterial pathogen, Bacillus anthracis, is enzootic in Kruger National Park (KNP), South Africa and Etosha National Park (ENP), Namibia. These parks share many of the same potential host species, yet the main anthrax host in one (greater kudu (Tragelaphus strepsiceros) in KNP and plains zebra (Equus quagga) in ENP) is only a minor host in the other. We investigated species and spatial patterns in anthrax mortalities, B. anthracis exposure, and the ability to neutralize the anthrax lethal toxin to determine if observed host mortality differences between locations could be attributed to population-level variation in pathogen exposure and/or immune response. Using serum collected from zebra and kudu in high and low incidence areas of each park (18- 20 samples/species/area), we estimated pathogen exposure from anti-protective antigen (PA) antibody response using enzyme-linked immunosorbent assay (ELISA) and lethal toxin neutralization with a toxin neutralization assay (TNA). Serological evidence of pathogen exposure followed mortality patterns within each system (kudus: 95% positive in KNP versus 40% in ENP; zebras: 83% positive in ENP versus 63% in KNP). Animals in the high-incidence area of KNP had higher anti-PA responses than those in the low-incidence area, but there were no significant differences in exposure by area within ENP. Toxin neutralizing ability was higher for host populations with lower exposure prevalence, i.e., higher in ENP kudus and KNP zebras than their conspecifics in the other park. These results indicate that host species differ in their exposure to and adaptive immunity against B. anthracis in the two parks. These patterns may be due to environmental differences such as vegetation, rainfall patterns, landscape or forage availability between these systems and their interplay with host behavior (foraging or other risky behaviors), resulting in differences in exposure frequency and dose, and hence immune response.NSF Division of Environmental Biology.https://www.frontiersin.org/journals/immunologydm2022Veterinary Tropical Disease

Environmental drivers of biseasonal anthrax outbreak dynamics in two multihost savanna systems

Environmental factors are common forces driving infectious disease dynamics. We compared interannual and seasonal patterns of anthrax infections in two multihost systems in southern Africa: Etosha National Park, Namibia, and Kruger National Park, South Africa. Using several decades of mortality data from each system, we assessed possible transmission mechanisms behind anthrax dynamics, examining (1) within- and between-species temporal case correlations and (2) associations between anthrax mortalities and environmental factors, specifically rainfall and the Normalized Difference Vegetation Index (NDVI), with empirical dynamic modeling. Anthrax cases in Kruger had wide interannual variation in case numbers, and large outbreaks seemed to follow a roughly decadal cycle. In contrast, outbreaks in Etosha were smaller in magnitude and occurred annually. In Etosha, the host species commonly affected remained consistent over several decades, although plains zebra (Equus quagga) became relatively more dominant. In Kruger, turnover of the main host species occurred after the 1990s, where the previously dominant host species, greater kudu (Tragelaphus strepsiceros), was replaced by impala (Aepyceros melampus). In both parks, anthrax infections showed two seasonal peaks, with each species having only one peak in a year. Zebra, springbok (Antidorcas marsupialis), wildebeest (Connochaetes taurinus), and impala cases peaked in wet seasons, while elephant (Loxodonta africana), kudu, and buffalo (Syncerus caffer) cases peaked in dry seasons. For common host species shared between the two parks, anthrax mortalities peaked in the same season in both systems. Among host species with cases peaking in the same season, anthrax mortalities were mostly synchronized, which implies similar transmission mechanisms or shared sources of exposure. Between seasons, outbreaks in one species may contribute to more cases in another species in the following season. Higher vegetation greenness was associated with more zebra and springbok anthrax mortalities in Etosha but fewer elephant cases in Kruger. These results suggest that host behavioral responses to changing environmental conditions may affect anthrax transmission risk, with differences in transmission mechanisms leading to multihost biseasonal outbreaks. This study reveals the dynamics and potential environmental drivers of anthrax in two savanna systems, providing a better understanding of factors driving biseasonal dynamics and outbreak variation among locations.The National Science Foundation of South Africa.https://onlinelibrary.wiley.com/r/ecmam2023Veterinary Tropical Disease

Exposure of wildlife to anthrax in Kruger and Etosha National Parks and the effect of haemoparasite coinfections

Anthrax has a global distribution and it is enzootic in Kruger National Park (KNP) in South Africa and Etosha National Park (ENP) in Namibia. These parks share some similarities such as hosts species and both have endemic and non-endemic areas, but host species differ in their susceptibility between the parks. We measured the presence of anti-PA antibodies in zebra and kudu from both parks using ELISA and also their ability to neutralize anthrax lethal toxin vis-à-vis haemoparasite coinfections detected with reverse line blot probes of Theileria, Babesia, Anaplasma and Ehrlichia. It was found that kudus in KNP had higher titres and proportion (95%) of positive animals than ENP (40%). ENP zebras had higher titres and proportions of positive animals (83%) than those of KNP (63%). Animals in anthrax endemic areas in KNP had higher titres than those in non-endemic areas, but this was not so in ENP. ENP kudus and KNP zebras showed better and higher proportion of neutralization. Animals positive to haemoparasites (Theileria, Babesia, Ehrlichia and Anaplasma) showed a significant difference between the kudu in KNP (100%) compared to 70% in ENP, while all ENP zebra (100%) tested positive compared to 84.6% KNP zebra. An increase in toxin neutralization was significantly associated with less likelihood of infection with haemoparasites in zebras. In summary, this study shows that rarity is largely a function of resistance toward anthrax, which could have emanated from both the dose of infection and the interval between exposures and the interplays of other infections in the host.Dissertation (MSc (Veterinary Science Tropical Diseases))--University of Pretoria, 2020.Veterinary Tropical DiseasesMSc (Veterinary Science Tropical Diseases)Unrestricte

Community Engagement newsletter, Faculty of Veterinary Science, Winter 2023

News articles with colour photos about the various community engagement projects of the Faculty of Veterinary Science, University of Pretoria.News articles with colour photos about the various community engagement projects of the Faculty of Veterinary Science, University of Pretoria.ab202