Research Articles (Veterinary Tropical Diseases)

Permanent URI for this collectionhttp://hdl.handle.net/2263/1710

News

For inquiries regarding this collection or items in the collection, please contact Tertia Coetsee Tel.: +27 12 420 8580

Browse

Now showing 1 - 20 of 1288

Seroprevalence and risk factors associated with Brucellosis in goats in Nyagatare District, Rwanda
(Wiley, 2025-08) Habimana, Jean Paul; Ntivuguruzwa, Jean Bosco; Uwimana, Aime Lambert; Ugirabe, Marie Aurore; Gasana, Eric; Van Heerden, Henriette
Given the endemic nature of bovine brucellosis in Rwanda, caprine brucellosis, primarily caused by Brucella melitensis in goats, may also be prevalent. However, no data exist on the disease’s prevalence and associated risk factors in goats, particularly in Nyagatare district. A cross-sectional study was therefore conducted to determine the seroprevalence of brucellosis and to identify herd-level risk factors associated with the disease among goat herds (n = 102) across six sectors of Nyagatare district. Serum samples from 612 goats were tested using both the indirect enzyme-linked immunosorbent assay (i-ELISA) and the Rose Bengal Test (RBT), applied in parallel. A systematic questionnaire, pretested for reliability, was used to gather data on potential risk factors for caprine brucellosis. The study found a brucellosis true adjusted seroprevalence of 6.08% and 10.7% using RBT and i-ELISA, respectively. When combining the results from both tests, the overall seroprevalence was 6.08% at the animal level and 16.6% at the herd level. The most significant risk factors for Brucella seropositivity were mixing of cattle and goats within the same herd and a history of abortions in the herd (p < 0.05). This study confirms that caprine brucellosis is endemic in Nyagatare district, highlighting the need for a One Health approach to control and prevent the disease in both livestock and humans. The study recommends implementing awareness campaigns to educate livestock farmers about brucellosis and calls for further research to characterize Brucella spp. in small ruminants in Rwanda and to establish appropriate control measures.
Predicting tick distributions in a changing climate : an ensemble approach for South Africa
(Elsevier, 2025-08) Motloung, R.F.; Chaisi, Mamohale E.; Sibiya, M.S.; Nyangiwe, N.; Shivambu, T.C.
Predicting the potential distribution of disease vectors is crucial for vector management and disease transmission surveillance. This study aims to assess changes in the geographic projection of the ecological niche of ticks of veterinary, public health, and economic importance in South Africa, and to predict areas suitable for their establishment under current and future climate scenarios. We used a suite of six algorithms within the ensemble modelling framework of the biomod2 package in R version 4.4.2 to produce species distribution models for current (2021–2040) and future (2041–2060) climate scenarios. Six bioclimatic variables, representing a range of biophysical and anthropogenic factors, were used in combination with tick presence-only occurrence data submitted to SANBI’s Integrated Publishing Toolkit by tick species experts. The model outputs indicate that all 10 tick species will likely experience range shifts over time (2021–2060). All species are projected to gain significant portions of suitable ranges in the future. Notably, Rhipicephalus microplus is predicted to gain the most, with a 14 % increase in its suitable range in South Africa. This predicted range expansion could potentially disrupt ecological balances in the ecosystems it is likely to occupy. Native species such as Amblyomma hebraeum and Hyalomma rufipes are predicted to expand their ranges by 10 and 9 %, respectively, while others may gain less than 6 % of their potential ranges The overall predicted range expansion could also introduce new disease dynamics, potentially leading to increased pathogen transmission, host switching and higher incidences of diseases in humans and animals in currently unaffected areas. The study provides baseline information to support ongoing monitoring and adaptive management strategies to mitigate the negative impacts associated with ticks on ecosystems, public health, and agriculture. The results will help inform tick control programs in South Africa and other similar environments. South Africa must adopt a comprehensive One Health approach to tick management to address the challenges posed by invasive species like R. microplus, which threaten livestock health and have significant veterinary and economic impacts. HIGHLIGHTS • Distribution models developed for 10 zoonotic tick species in South Africa. • An innovative ensemble modelling framework utilized. • Assessed the impact of climate change on zoonotic ticks. • Addressed a critical gap on regional tick distribution data. • Closely related tick species are likely to increase their range sizes.
Smart farming with AI : enhancing anemia detection in small ruminants
(Elsevier, 2025-08) Siddique, Aftab; Khan, Sophia; Terrill, Thomas H.; Mahaptra, Ajit K.; Panda, Sudhanshu S.; Morgan, Eric R.; Pech-Cervantes, Andres A.; Randall, Reginald; Singh, Anurag; Batchu, Phaneendra; Gurrapu, Priyanka; Van Wyk, Jan Aucamp; jan.vanwyk@up.ac.za
Accurate classification of FAMACHA© scores is essential for assessing anemia in small ruminants and optimizing parasite management strategies in livestock agriculture. The FAMACHA© system categorizes anemia severity on a scale from 1 to 5, where scores 1 and 2 indicate healthy animals, score 3 represents a borderline condition, and scores 4 and 5 indicate severe anemia. In this study, a dataset of 4700 images of the lower eye conjunctiva of young male goats was collected weekly over six months using a Samsung A54 smartphone. Traditional FAMACHA© assessment methods rely on subjective visual examination, which is labor-intensive and susceptible to observer bias. To address this limitation, this study implemented machine learning algorithms to automate FAMACHA© classification, leveraging Support Vector Machine (SVM), Backpropagation Neural Network (BPNN), and Convolutional Neural Network (CNN) models. A comparative analysis of these models was conducted using precision, recall, F1-score, and accuracy metrics. The CNN model demonstrated the highest classification accuracy (97.8 %), outperforming both BPNN and SVM. The SVM model achieved a mean accuracy of 84.6 %, with strong performance in severe anemia detection, but limitations in intermediate classes. The overall accuracy of 84 % attained by the BPNN model provided a balanced tradeoff between precision and recall. The CNN model’s superior performance was attributed to its ability to learn spatial and contextual patterns from images, ensuring robust classification across all FAMACHA© categories. These findings underscore CNN’s potential as a reliable, scalable solution for automated anemia detection in livestock, facilitating early intervention and improving herd health management. The study also highlights the need for future research to explore ensemble learning approaches and integration with mobile applications for real-time deployment for both commercial and resource-limited livestock producers.
A single-centre retrospective study of surgical site infection following equine colic surgery (2013-2021)
(Wiley, 2025-05) Griessel, Theunis Steyn; Moran, Juan Alberto Munoz; Byaruhanga, Charles; Smit, Yolandi
BACKGROUND : Surgical site infection (SSI) is a significant cause of postoperative morbidity following equine laparotomy. Therefore, if risk factors for SSI can be identified, morbidity may consequently be reduced. The objectives of this study were to determine the prevalence of SSI in horses undergoing exploratory laparotomy at a single hospital over an 8-year period (2013‒2021), investigate the risk factors associated with SSI and report on the bacterial isolates identified. METHODS : The medical records of horses that had an exploratory laparotomy performed at the teaching hospital due to colic were retrospectively reviewed. SSI was defined as any purulent or serous discharge from the laparotomy incision for more than 24 hours duration during hospitalisation. Pre-, intra- and postoperative risk factors for SSI were identified using multivariable logistic regression analysis. RESULTS : A total of 143 horses met the criteria for inclusion in the study, of which 38 developed an SSI (26.6%, 95% confidence interval: 19.5–34.6%). Multivariable analysis revealed that the application of a postoperative abdominal bandage was significantly associated with a decreased likelihood of SSI (odds ratio = 0.29, p = 0.026). LIMITATIONS : As this was a retrospective study performed at a single hospital, the findings may have limited generalisability. CONCLUSIONS : The application of a postoperative abdominal bandage is protective against SSI in horses following exploratory laparotomy for colic.
GAVI investment should accelerate rabies “zero by 30” aspiration
(Elsevier, 2024-12) Salahuddin, Naseem; Blumberg, Lucille Hellen; Abela, Bernadette; Durrheim, David N.
Rabies has been known to humankind for at least 4000 years. In Eastern culture, rabies was considered a “curse,” ordained by destiny, to be treated by mystics and mendicants, but inevitably ending in agonizing, torturous death. Around 59,000 rabies deaths still occur annually, and rabies remains a significant public health problem in many countries in Asia, South and Central America, and Africa, where unvaccinated, unowned, and stray dogs roam freely. The highest-risk countries for travelers include Bolivia, China, Haiti, Nepal, Philippines, Pakistan, India, Sri Lanka, Thailand, and Vietnam. Most human rabies infections in the Americas and Europe are due to rabid wild animal bites, including bats. Rabies has the highest fatality rate of any infectious disease. Although great strides have been made in making safe and effective vaccines, these do not reach all those ex posed, hence the mortality due to rabies continues unabated.
Widespread infections with bacterial and protozoan tick-borne pathogens in 22 wildlife species across South African game reserves
(Elsevier, 2025-10) Cossu, Carlo Andrea; Quan, Melvyn; Collins, Nicola E.; Wentzel, Jeanette Maria; De Klerk, Lin Mari; Van Schalkwyk, Ockert Louis; Vorster, Ilse; Oosthuizen, Marinda C.; Neves, Luís C.B.G.; Bhoora, Raksha Vasantrai; Van Heerden, Henriette; ca.cossu@tuks.co.za
Tick-borne pathogens (TBPs) are a growing global concern, contributing to emerging and re-emerging diseases in humans and animals. Human encroachment into natural habitats and unregulated wildlife translocations are key drivers of TBP emergence, as they expand wildlife–livestock–human interfaces and facilitate the introduction of alien TBPs into naïve hosts and new regions. Accurate molecular surveillance is essential to guide management strategies and prevent clinical outbreaks. This study conducted a cross-sectional molecular screening of TBPs in wildlife from 22 host species sampled over a four year period from 2021 to 2024 across eight South African protected areas: Kruger (KNP), Karoo (KaNP), Camdeboo (CaNP), Mountain Zebra (MZNP), Mokala (MokNP), and Addo Elephant (AENP) National Parks, as well as Lapalala Wilderness (LWR), and Timbavati (TPNR) Nature Reserves. A total of 572 spleen, liver and blood samples were tested for Anaplasma, Ehrlichia, Rickettsia, Coxiella, Theileria and Babesia spp. using Reverse Line Blot hybridization, with confirmation by Sanger sequencing and phylogenetic analysis. Prevalence, confidence intervals, risk factors and co-infections were also assessed. High prevalence (50–100 %) of Anaplasma/Ehrlichia and Theileria/Babesia spp. was recorded. Anaplasma marginale was detected in African buffalo (Syncerus caffer; KNP), kudu (Tragelaphus strepsiceros; CaNP), warthog (Phacochoerus africanus; AENP), hippo (Hippopotamus amphibius; TPNR), and eland (Taurotragus oryx; KaNP), while zoonotic A. capra was found in a hippo. Coxiella burnetii was detected in all sampled areas and in multiple species, including African buffalo, wild dog (Lycaon pictus), black wildebeest (Connochaetes gnou), eland, gemsbok (Oryx gazella), zebra (Equus quagga), hartebeest (Alcelaphus buselaphus), springbok (Antidorcas marsupialis), and warthog. SFG Rickettsia spp., including R. africae and R. felis, were detected in 18 animals. Babesia bigemina was found in springbok (MokNP). These findings reveal widespread TBP presence in South African wildlife and highlight the need for ongoing surveillance to mitigate spillover risks and protect ecosystems and public health. While high prevalences were observed, clinical impacts of these infections on wildlife remain unclear. HIGHLIGHTS • Large-scale molecular screening of TBPs in 22 wildlife species. • Non-buffalo bovids host diverse TBPs, raising concerns with animal translocations. • Zoonotic A. capra, C. burnetii and SFG Rickettsia spp. detected in multiple hosts. • A. marginale like organisms found in wild dog, hippo, warthog. • B. bigemina in springboks from Mokala National Park; vectors may be shifting.
The first cryptic genus of ixodida, cryptocroton n. gen. for amblyomma papuanum hirst, 1914 : a tick of North Queensland, Australia, and Papua New Guinea
(Magolia Press, 2024-02-12) Barker, Stephen C.; Kelava, Samuel; Mans, Ben J. (Barend Johannes); Apanakevich, Dmitry A.; Seeman, Owen D.; Gofton, Alexander; Shao, Renfu; Teo, Ernest J.M.; Evasco, Kimberley; Soennichsen, Kari F.; Barker, Dayana; Nakao, Ryo
We describe a new genus Cryptocroton n. gen. for Amblyomma papuanum Hirst, 1914, a tick of North Queensland, Australia, and Papua New Guinea.
Molecular evidence of Brucella abortus circulating in cattle, goats, and humans in Central Equatoria State, South Sudan
(Nature Research, 2025-04) Lita, Emmanuel P.; Mkupasi, Ernatus M.; Ochi, Erneo B.; Misinzo, Gerald; Van Heerden, Henriette; Katani, Robab; Godfroid, Jacques; Mathew, Coletha
Brucellosis is a neglected zoonotic disease in most developing countries, including South Sudan. Precise identification of Brucella species is crucial for addressing public health and epidemiological concerns associated with brucellosis. The study aimed to identify Brucella species using real-time polymerase chain reaction (qPCR) from seropositive samples that were acquired from an earlier investigation. A total of 143 genomic DNA samples were extracted from brucellosis Rose Bengal plate test (RBPT) seropositive samples from humans (n = 7), cattle (n = 103) and goats (n = 33). The samples were collected from Terekeka and Juba counties, Central Equatoria State (CES), South Sudan. The qPCR targeting the Brucella-specific IS711 insertion gene at the genus level was performed. Samples with a cycle threshold (Ct) of ≤ 35 were considered positive and subjected to further Brucella speciation assays. Out of 143 DNA samples tested for genus-specific Brucella, 15 (10.5%) were positive including 4 (2.8%) from humans, 10 (6.9%) from cattle, and 1 (0.7%) from goats. Brucella abortus was identified in 5 (33.3%) of the positive samples at the genus level. The overall individual species infection rates with B. abortus were 6.6% (1/15) in humans, 20% (3/15) in cattle, and 6.6% (1/15) in goats. There was no B. melitensis detected in this study. This study identified B. abortus in cattle, goats and humans in CES, South Sudan. The findings suggest that cattle are probably the primary reservoirs for transmission of B. abortus, with infections occurring in goats and humans primarily resulting from cattle spillover.
A standardized pipeline for assembly and annotation of African swine fever virus genome
(MDPI, 2024-08-13) Spinard , Edward; Dinhobl , Mark; Erdelyan, Cassidy N.G.; O’Dwyer , James; Fenster , Jacob; Birtley , Hillary; Tesler, Nicolas; Calvelage , Sten; Leijon , Mikael; Steinaa , Lucilla; O’Donnell , Vivian; Blome, Sandra; Bastos, Armanda D.S.; Ramirez-Medina , Elizabeth; Lacasta , Anna; Stahl, Karl; Qiu , Huaji; Nilubol , Dachrit; Tennakoon , Chandana; Maesembe , Charles; Faburay, Bonto; Ambagala , Aruna; Williams , David; Ribeca , Paolo; Borca , Manuel V.; Gladue, Douglas P.
Obtaining a complete good-quality sequence and annotation for the long double-stranded DNA genome of the African swine fever virus (ASFV) from next-generation sequencing (NGS) technology has proven difficult, despite the increasing availability of reference genome sequences and the increasing affordability of NGS. A gap analysis conducted by the global African swine fever research alliance (GARA) partners identified that a standardized, automatic pipeline for NGS analysis was urgently needed, particularly for new outbreak strains. Whilst there are several diagnostic and research labs worldwide that collect isolates of the ASFV from outbreaks, many do not have the capability to analyze, annotate, and format NGS data from outbreaks for submission to NCBI, and some publicly available ASFV genomes have missing or incorrect annotations. We developed an automated, standardized pipeline for the analysis of NGS reads that directly provides users with assemblies and annotations formatted for their submission to NCBI. This pipeline is freely available on GitHub and has been tested through the GARA partners by examining two previously sequenced ASFV genomes; this study also aimed to assess the accuracy and limitations of two strategies present within the pipeline: reference-based (Illumina reads) and de novo assembly (Illumina and Nanopore reads) strategies.
Rabies in cats—an emerging public health issue
(MDPI, 2024-10-19) Fehlner-Gardiner , Christine; Gongal , Gyanendra; Tenzin, Tenzin; Sabeta, Claude Taurai; De Benedictis , Paola; Rocha , Silene Manrique; Vargas , Alexander; Cediel-Becerra, Natalia; Gomez , Luis Carlos; Maki , Joanne; Rupprecht, Charles E.; claude.sabeta@up.ac.za
Human rabies cases today are predominantly associated with infection from rabid domestic dogs. Unlike dogs, a common global reservoir species that perpetuates rabies viruses (RABV) within their populations, domestic cats are much less frequently reported or vaccinated. Epidemiologically, cats are important vectors of lyssaviruses but are not viral reservoirs. Typically, cats are incidental hosts only, infected with the predominant lyssavirus in their geographic locale. Human cases associated with rabid cats have occurred in Africa, Asia, Europe and throughout the Americas. As adept, solitary hunters, wild and domestic felids are at risk of lyssavirus infection based upon interactions with infected prey, such as bats, or from transmission by other mesocarnivores, such as rabid dogs, foxes, jackals, raccoons, and skunks. Current veterinary vaccines provide safe and effective immunity in cats against phylogroup I lyssaviruses, such as RABV, but not against divergent lyssaviruses in phylogroups II-IV. With the focus upon the global elimination of canine rabies, the emergence of rabies in cats represents a concerning trend. Clearly, education about the occurrence of rabies in cats needs to be improved, as well as the routine vaccination of cats to reduce the associated risks to public health, agriculture, and conservation biology from a One Health perspective.
Sequence- and structure-based bioinformatic screening for potential Theileria parva transport-related proteins
(Elsevier, 2026-02) Kotsovolos, Nikolaos; Schnittger, Leonhard; Sibeko-Matjila, Kgomotso Penelope; u14196973@tuks.co.za
As an obligate intracellular parasite, Theileria parva is strictly dependent on its host for nutrient acquisition. Transport proteins are expected to play a crucial role in the influx of essential nutrients to sustain the parasite’s rapid growth. Unfortunately, the T. parva transportome is still not comprehensively elucidated, and plagued by the presence of uncharacterized proteins. In this study, we employed a combination of approaches including sequence orthology and structural similarity to identify 188 proteins predicted to be involved in transport-related processes. Among these, 24 were uncharacterized proteins, and 17 of them could be assigned a tentative annotation. Furthermore, the localization of these 188 proteins was investigated, resulting in their assignment to seven cellular compartments. Screening of the proteomes of other Theileria species, T. annulata, T. orientalis, and T. equi revealed that all 188 proteins were present in both transforming and non-transforming Theileria parasites. Among the 188 potential transport-related proteins, 45 were associated with transmembrane transport and most of them (87 %) are conserved across phylum Apicomplexa. HIGHLIGHTS • A set of 188 potential transport-related proteins were identified in Theileria parva • Tentative annotations assigned to 17 transport-related uncharacterized proteins • Subcellular localization predicted for 153 of 188 proteins
Prioritising intervention areas for antimicrobial resistance in Nigeria's human and animal health sectors using a mixed-methods approach
(Elsevier, 2025-06) Awulu, Oche A.; Jenkins, Akinbowale; Balogun, Babatunde A.; Chukwu, Emelda E.; Fasina, Folorunso Oludayo; Egwuenu, Abiodun; Oduyebo, Oyinlola O.; Bamidele, Tajudeen A.; Cadmus, Simeon; Aworh, Mabel K.; Adekola, Adewole A.; Desbois, Andrew P.; Chah, Kennedy F.; Brunton, Lucy A.
A One Health approach is essential to prioritise intervention areas to tackle antimicrobial resistance (AMR). This study aimed to identify and evaluate critical drivers and antimicrobial stewardship (AMS) challenges within Nigeria's human and animal health sectors. Human (22) and animal (33) health professionals in Nigeria were asked via an online questionnaire to rank priority pathogens, AMS challenges, and AMR drivers identified by subject matter experts. Descriptive statistics and the Fisher's exact test were used to evaluate differences in rankings between sectors. Subsequently, a scoping literature review of peer-reviewed research and grey literature was conducted to evaluate the evidence supporting the rankings. Salmonella spp. (28.5 %) and Escherichia coli (28.2 %) were selected as the top-ranked priority pathogens for AMR. The Fisher's exact test showed a significant association (p = 0.049) between profession and ranking of Salmonella, which was ranked higher by animal health professionals than their human health counterparts. Priority AMS challenges in both human and animal health sectors were “ease of access to over-the-counter antimicrobials” (14.9 % and 20.1 %, respectively) and “lack of awareness of AMR/AMS” (14.1 % and 20.4 %, respectively). “Lack of infection prevention and control (IPC)” (24.5 %) was the highest-ranked AMR driver across sectors. Differences were observed between the rankings human and animal health professionals gave to the challenge of access to veterinary expertise (p = 0.011), as medical doctors ranked this component higher than veterinarians. “Lack of IPC” (p = 0.022) and “environmental degradation” (p = 0.048) were ranked higher by medical doctors than veterinarians. Conversely, “unsanitary processes in the abattoir(s)” was ranked higher among veterinarians (p = 0.032). Of the 84 articles reviewed, 62 supported the rankings of AMS challenges in both sectors, while 24 captured relevant AMR drivers. Our findings underscore the need for a One Health approach in Nigeria to improve AMS and curb AMR.
Antibiotic resistance profiles of oral flora in hippopotami (Hippopotamus amphibius) : implications for treatment of human bite wound infections
(BioMed Central, 2025-04) Michel, Anita Luise; Engelbrecht, Maralize; Roux, Francois; Wentzel, Jeanette Maria; Jonker, Annelize; anita.michel@up.ac.za
BACKGROUND : The common hippopotamus (Hippopotamus amphibius) is found in aquatic environments throughout sub-Saharan Africa and is known to cause attacks on humans living or working close to water bodies. Victims surviving an attack often suffer from the consequences of severe wound infections caused by the animal’s sharp canine teeth. OBJECTIVE : Isolation of normal flora bacteria from the oral cavity of common hippopotami (Hippopotamus amphibious) followed by antibiotic susceptibility testing to aid in the identification of a targeted antibiotic treatment regimen for hippopotamus attack victims. METHODS : Oral swabs were collected from 34 free-ranging hippopotami in three reserves within the Greater Kruger National Park Complex in South Africa and cultured for aerobic and anaerobic bacteria. Antibiotic susceptibility testing was conducted using the disc diffusion method (Kirby-Bauer method) and a panel of 16 antibiotic drugs representing 10 antibiotic categories. RESULTS : Culturing of 50 oral swab samples from 34 hippopotami yielded 188 aerobic isolates belonging to 30 bacterial genera and 41 bacterial species (Gram-negative: 70.7%; Gram-positive: 29.3%) and 16 obligate anaerobic isolates from two genera. Three bacterial species, namely Aeromonas hydrophila, Aeromonas sobria and Shewanella putrefaciens accounted for 52% of the aerobic isolates. The anaerobic isolates were identified as Prevotella melaninogenica and Clostridium spp. Antimicrobial susceptibility testing was performed for 112 aerobic isolates (Gram-negative: 93 (83%); Gram-positive: 19 (17%)) representing all isolated bacterial species. High levels of antibiotic resistance were observed among the Gram-negative species especially to most beta-lactam antibiotics (50.5% to 80.7%). Multidrug resistance was detected in 22.6% of Gram-negative isolates and in 24.1% of all isolates. CONCLUSIONS : This study provides the first investigation of the oral flora bacteria of the common hippopotamus. Among the 32 mostly aerobic bacterial genera the most abundant bacterial species were A. hydrophila, A. sobria and S. putrefaciens. They are typical inhabitants of the aquatic habitat of the hippopotamus and of zoonotic importance as opportunistic human pathogens. The antibiotic susceptibility profiles demonstrated that quinolones, aminoglycosides, and tetracyclines were highly efficacious against these bacterial species which otherwise showed moderate to high levels of resistance to the traditional bite wound treatment with amoxicillin/clavulanate and 1st and 2nd generation cephalosporins.
Perceptions on anthelmintic use and resistance development in goats under communal production systems
(BioMed Central, 2025-07) Ndwandwe, Khanyisani Cyril; Chimonyo, Michael; Tsotetsi-Khambule, Ana; Marufu, Munyaradzi Christopher; chris.marufu@up.ac.za
For decades, farmers relied on anthelmintic drug treatments to control gastrointestinal nematode (GIN) infections, which has led to the development of anthelmintic resistance (AR). The objective of this study was to investigate the perceptions of communal goat farmers regarding anthelmintic resistance in communal goat flocks. A structured, close-ended questionnaire was used to carry out face-to-face interviews with communal goat farmers (n = 384) across four local municipalities in the uMkhanyakude district. The results showed that elderly farmers were 1.4 times more likely to underdose compared to younger farmers (p < 0.05). Educated farmers were aware of the negative influence on AR development brought by using substandard drugs (p < 0.01) and repetitive use of one drug (p < 0.05). However, lack of professional veterinary assistance (p < 0.01) resulted in more than 65% of elderly farmers underdosing the anthelmintic drugs (p < 0.05) while 68% were using expired drugs (p < 0.05). Despite varying levels of education, most farmers treated goats only showing GIN infection signs (p < 0.05) in their flocks which can potentially delay the AR development. The elderly farmers are less likely to delay the development of AR due to their inability to adhere to the recognized principles of responsible and sustainable drug use. Despite reasonable awareness of AR as a problem in their flocks, communal farmers proved to have poor perceptions regarding the development of AR. This was attributed to old age, illiteracy and under dosing. Engaging veterinarians, farmers and animal health technicians could achieve sustainable management of GIN infections.
Temporal and spatial analysis of rabies virus lineages in South Africa
(MDPI, 2025-02) Viljoen, Natalie; Sabeta, Claude Taurai; Markotter, Wanda; Weyer, Jacqueline
Rabies virus (RABV; species Lyssavirus rabies) causes rabies, a disease of the central nervous system that invariably results in the death of the host. In South Africa, studies have indicated that RABV is maintained by animal species that include four wildlife carnivore species—the black-backed jackal (Canis mesomelas), bat-eared fox (Otocyon megalotis), yellow mongoose (Cynictis penicillata), and aardwolf (Proteles cristatus)—and domestic dogs (Canis lupus familiaris). The complex natural ecology holds significant implications for the control and elimination of rabies. In this study, confirmed animal rabies case data, including geospatial features, were analyzed for 12,879 laboratory-confirmed animal cases reported on a database managed by the Department of Agriculture, Land Reform and Rural Development (DALRRD). Sequence data generated from animal rabies cases in South Africa were also analyzed, which included 1374 cytoplasmic domain of the glycoprotein and the G-L intergenic sequences using maximum likelihood (ML) and Bayesian inference. The analysis provides insights into the transmission dynamics involving several wildlife species and domestic dogs in South Africa. This information is crucial for the strategic planning for rabies control and elimination programs, and particularly in understanding the interlinked nature of some lineages and the importance of the cross-border spread of rabies. This analysis provided an improved understanding of the distribution of the RABV lineages in South Africa and identified areas that can be targeted for rabies control strategies to limit future spread of RABV, which is important due to the limited available resources that must be carefully managed to allow optimal control.
A multi-modal investigation into the prevalence and diagnostic evaluation of vector-borne pathogens and retroviruses in domestic cats throughout Namibia
(Elsevier, 2025-08) De Villiers, Lourens; Penzhorn, Barend Louis; Schoeman, Johan P.; Molini, Umberto; De Villiers, Mari; Byaruhanga, Charles; Makgabo, Sekgota Marcus; Collins, Nicola E.; Zealand, Samantha; Baines, Ian J.M.; Stoltsz, Wilhelm Heinrich; Thompson, P.N. (Peter N.); Oosthuizen, Marinda C.
Neglected, but economically significant, tropical diseases may be prevalent in domestic cats of Namibia. A multi-centre prevalence field study was conducted across Namibia to assess the distribution of vector-borne pathogens and retroviruses from domestic cats. Samples of blood and serum from 280 cats in 15 towns across eight regions (22–51 cats per region) were analysed. Screening for Ehrlichia, Anaplasma, Babesia, and Hepatozoon species, as well as feline leukaemia virus (FeLV) and feline immunodeficiency virus (FIV), was conducted using light microscopy, point-of-care serology, and quantitative real-time polymerase chain reaction (qPCR) assays. Haematology and serum biochemistry analyses were also performed. Several pathogens were identified in Namibian cats using these diagnostic tools. Comparatively, pathogen detection rates varied by modality, namely light microscopy (5 %), serology (42 %), and qPCR (27 %). More specifically, microscopy revealed an overall prevalence (3 %) for inclusions resembling large Babesia parasites, serology indicated a seroprevalence for FIV antibodies (4 %) and FeLV antigen (40 %), and an overall prevalence determined by qPCR for E. canis (2 %) and H. canis (26 %). The investigation also demonstrated the associations between tick presence, pathogen infection, and disease manifestations in Namibian cats. A particular significant positive association was found between H. canis infection and FeLV antigen seroprevalence (P = 0.005). Overall, the study highlighted the difference of various diagnostic tools for detecting pathogen prevalence in cats. Appropriate diagnostic testing - informed by known associations with disease manifestation - should be key in guiding responsible treatment strategies and evaluating potential zoonotic risks linked to domestic cats of Namibia. HIGHLIGHTS • First comprehensive survey of vector-borne diseases and retroviruses in domestic cats across several Namibian regions. • First confirmed detection of Ehrlichia canis and Hepatozoon canis in domestic feline blood across several regions of Namibia. • Demonstrated significant associations between pathogen infection, tick presence, and disease manifestation.
Ehrlichia ruminantium (Ehrlichiaceae) infection rates and genotyping in Amblyomma species from southern Africa
(Elsevier, 2025-05) Smit, Andeliza; Mulandane, Fernando C.; Wojcik, Stephane H; Malabwa, Choolwe; Sili, Gourgelia; Mandara, Stephen; Pineau, Kaissa Plaisir; Lecollinet, Sylvie; Exbrayat, Antoni; Rodrigues, Valerie; Vineer, Hannah Rose; Dlamkile, Zinathi; Stoltsz, Wilhelm Heinrich; Meyer, Damien F.; Morar-Leather, Darshan; Makepeace, Benjamin L.; Neves, Luís C.B.G.; u14023190@tuks.co.za
Ticks are haematophagous ectoparasites of domestic and wild animals. With their vast geographical distribution and aptitude as vectors of a large variety of pathogens, they are ranked amongst the top two arthropod families of veterinary and medical concern. Amblyomma, the third largest genus in the Ixodidae, is important in southern Africa due to its vector competence for Ehrlichia ruminantium and other pathogens. Ehrlichia ruminantium, the causative agent of heartwater, a potentially lethal disease in ruminants, is classified as a notifiable disease by the World Organisation for Animal Health. Amblyomma species ticks were collected in five southern African countries from livestock and wildlife. They were morphologically identified to species level with taxonomic keys, and species identity was confirmed with molecular assays. Preliminary screening for E. ruminantium was conducted by targeting the pCS20 gene fragment. Genotyping of 39 E. ruminantium positives was obtained using Ampliseq technology. In total, 7,734 Amblyomma ticks were collected and identified as belonging to four species: Amblyomma eburneum, Amblyomma hebraeum, Amblyomma pomposum and Amblyomma variegatum. Ehrlichia ruminantium infection rates per country ranged from 7.1 % to 34.1 %. The genotyping analysis indicated the clustering of our sequences with strains Gardel, Welgevonden, Um Banein, Springbokfontein 4 and 2, Kwanyanga, and Blaauwkrans. The Ampliseq analysis was not effective in differentiating between strains found in southern Africa. This large study documents the genetic diversity and prevalence of E. ruminantium in ticks across southern Africa, highlighting implications for disease control and vaccine development.
In vitro infection of bovine erythrocytes with Theileria annulata merozoites as a key step in completing the T. annulata life cycle in vitro
(Nature Research, 2024-02-13) Elati, Khawla; Tajeri , Shahin; Mugo , Robert M.; Obara , Isaiah; Darghouth, Mohamed Aziz; Zweygarth, Erich; Nijhof, Ard Menzo
Theileria annulata is a protozoan parasite with a complex life cycle involving a bovine host and a tick vector. It is transmitted by Hyalomma ticks and is the causative agent of tropical theileriosis, a debilitating and often fatal disease in southern Europe, northern Africa and large parts of Asia. Understanding the biology of different life cycle stages is critical for the control of tropical theileriosis and requires the use of experimental animals which poses an ethical concern. We present for the first time the in vitro infection of red blood cells (RBCs) with T. annulata differentiated schizonts. The Ankara cell line of T. annulata was cultured at 41 °C for nine days to induce merogony and subsequently incubated with purified RBCs for one to three days. Percentage of parasitized erythrocyte (PPE) over the short culture period was estimated by Giemsa staining (0.007–0.01%), Flow cytometry activated sorting (FACS) (0.02–1.1%) and observation of FACS sorted cells by confocal microscopy (0.05–0.4%). There was a significant difference in the PPE between FACS and the two other techniques (one-way ANOVA followed by Tukey test, P = 0.004) but no significant difference was observed between the confocal imaging and Giemsa staining methods (ANOVA one-way followed by Tukey test, P = 0.06). Importantly, all three complementary methods confirmed the invasion of RBCs by T. annulata merozoites in vitro. Although the experimental conditions will require further optimization to increase the PPE, the in vitro infection of RBCs by T. annulata merozoites is pivotal in paving the way for the eventual completion of the T. annulata life cycle in vitro when combined with artificial tick feeding.
Indigenous ethno-nutraceutical plants : potential game-changers for the dual management of ruminant helminths and undernutrition in sub-Saharan Africa
(Elsevier, 2025-07) Mapiye, Cletos; Semwogerere, Farouk; Mahachi, Leo Nyikadzino; Mwale, Marizvikuru; Marufu, Munyaradzi Christopher
ETHNOPHARMACOLOGOCAL RELEVANCE : Ruminant productivity in sub-Saharan Africa (SSA) remains low largely due to helminth infections coupled with undernutrition. To jointly boost ruminant health and nutritional status, rural farmers in SSA often resort to indigenous ethno-nutraceutical plants (iENPs), which form part of folkloric practices perceived to be more accessible, affordable and effective compared with chemotherapy which is challenged by helminth resistance. However, these perceived advantages are largely unsubstantiated. AIM OF THE STUDY : The current review aimed to 1) identify iENPs used as ruminant anthelminthic and undernutrition remedies in SSA, 2) document their bio-efficiency, mode of action, safety, and optimal application conditions and 3) highlight priority areas for further research. MATERIALS AND METHODS : A PRISMA approach-based search of literature from the past three decades was performed in several electronic academic research databases and accredited scholarly repositories. RESULTS : The review identified 15 iENPs from 88 scientific articles. The Vachellia and Vernonia species possessing polyphenols, saponins and essential oils as the dominant phytochemicals demonstrated the highest anthelminthic and nutritional potency. However, for most iENPs, nutrients and phytochemicals have not been fully profiled, optimal conditions of application are not yet ascertained, bio-efficiency is highly variable, mode of action remains unclear, and safety limits are unknown. CONCLUSION : To exploit the full potential of SSA's iENPs as anthelminthic and undernutrition remedies for ruminants, the review advocates for a holistic, transdisciplinary regional approach focusing on identifying key phytochemicals in indigenous plants, validating their bio-efficacy and mechanisms of action, determining safety limits, and optimizing application conditions using least-cost technologies.
UP maak deurbraak met beesaborsie-diagnose
(Plaas Publishing, 2025-03) Marais, Susan; melvyn.quan@up.ac.za
Navorsers aan die Universiteit van Pretoria (UP) is positief dat hulle 'n deurbraak gemaak het om een van die beeswêreld se grootste probleme te help oplos, naamlik die redes waarom koeie aborteer.

Browse

Recent Submissions