Research Articles (Veterinary Tropical Diseases)

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Clinical canine Borrelia burgdorferi (sensu lato) infections are associated with highly elevated total IgG ELISA titers and convalescent Th2 immune responses
Hovius, K. Emil; Van den Bergen, Tess; Almalik, Osama; Versmissen, Ellen; Rutten, Victor P.M.G.; Sprong, Hein; Hovius, Joppe W. (Elsevier, 2025-04-08)
Lyme disease is caused by Borrelia burgdorferi (sensu lato), which is transmitted through species belonging to the Ixodes ricinus complex. Canine Lyme Disease (CLD) is an established clinical entity in the USA. In Europe, an unambiguous diagnosis is rarely made, although it has been shown that dogs can be naturally infected and develop antibodies against B. burgdorferi (s.l.). The relation of Borrelia total IgG, IgG2, and IgG1 specific antibodies and the incidence of symptoms was studied in a prospective cohort study. In a tick-dense area in the Netherlands, 84 dogs in 4 age cohorts were followed up during 7 consecutive half-years. In addition, 31 Bernese Mountain dogs (BMD), known to have robust anti-Borrelia antibody responses, were clinically monitored and serologically examined. Generalized estimating equations (GEE) analysis on repeated half-year measurements of clinical and serological results showed a strong association between the clinical signs fever combined with lameness in time, which in turn was associated with transiently high total IgG titers and elevated IgG1 titers against B. burgdorferi (sensu stricto). In BMD, we observed seroconversions and persistence of specific high total IgG and IgG1 titers. Although the latter also developed a persistent reaction against the B. burgdorferi (s.l.) C6 peptide, their tissues tested negative for B. burgdorferi (s.l.) DNA. This study strongly suggests that dogs - not vaccinated against Borrelia spp. infections - that encounter yearly tick infestations are recurrently infected. Some breeds, such as Labrador Retrievers and BMD, in the course of multiple tick-infestation seasons, develop transient symptoms compatible with CLD. Symptoms were strongly associated with temporarily raised total IgG and concomitant or convalescent high IgG1 antibody responses against B. burgdorferi (sensu stricto). Our findings provide insights into the resistance of dogs against B. burgdorferi (s.l.) infections and show that transient symptoms of CLD only occur in a subset of infected dogs.
Two decades of One Health in action : enabling sustainable wildlife conservation and livestock production in southern Africa
Osofsky , Steven A.; Atkinson, Shirley J.; Ramsden, Nidhi; Penrith, Mary-Louise (CAB International, 2025-04-16)
The AHEAD (Animal & Human Health for the Environment And Development) program was launched in 2003 at the IUCN World Parks Congress in Durban, South Africa. We defined our mission as serving as “a convening, facilitative mechanism, working to create enabling environments that allow different and often competing sectors to literally come to the same table and find collaborative ways forward to address challenges at the interface of wildlife health, livestock health, and human health and livelihoods.” We continue on this mission more than 20 years later, convening stakeholders, helping delineate conceptual frameworks to underpin planning, management and research, and providing technical support and resources for projects stakeholders identify as priorities. As one of the first applied One Health programs, our work is premised upon the fact that the challenge of managing transboundary animal diseases (TADs) often lies at the heart of whether transfrontier conservation areas (TFCAs) will succeed or fail in their aspirations to become the ecologically resilient land-use entities required for long-term delivery of poverty alleviation and related development as well as biodiversity conservation benefits. As the Kavango Zambezi Transfrontier Conservation Area’s (KAZA’s) remaining key wildlife corridors, needed for wildlife populations to survive and thrive for generations to come, continue to be blocked by veterinary cordon fences, the urgency of improving regional animal disease management cannot be overstated. This is especially relevant for those European donors to TFCAs whose nations set up the veterinary cordon fencing-based disease management system in the first place – starting in the 1950s when today’s KAZA partner countries were European colonies or protectorates. The prevailing veterinary fencing paradigm is rooted in the colonial era, but with impacts on KAZA’s wildlife that have persisted on up to the present. If we fail to help all countries within a given TFCA actually co-manage disease threats to the livestock sector that all value highly – culturally, economically, and politically – then how can we expect significant progress in terms of fostering habitat connectivity across international boundaries? When a given country fears diseases they believe or know are across the border, how can we lower the perceived or actual risks of the vision of restoring wildlife migrations through removal of segments of the most environmentally damaging fences? The AHEAD program continues to work on these challenges, with recent progress on sectorally integrative approaches providing reasons for cautious optimism. ONE HEALTH IMPACT STATEMENT What was arguably the first applied One Health program, AHEAD (Animal & Human Health for the Environment And Development) was launched in 2003 at the IUCN World Parks Congress in Durban – a year before one of us led the drafting of The Manhattan Principles on ‘One World, One Health’ (Cook et al ., 2004 ). As AHEAD has recently marked its 20th anniversary, some introspection certainly seems prudent. Our goal, our raison d’etre , has been to serve as ‘a convening, facilitative mechanism, working to create enabling environments that allow different and often competing sectors to literally come to the same table and find collaborative ways forward to address challenges at the interface of wildlife health, livestock health, and human health and livelihoods’ (available at: http://cornell ahead.org ). We continue on our One Health mission to convene stakeholders, help delineate conceptual frameworks to underpin planning, management and research, and provide technical support and resources for projects stakeholders identify as priorities. AHEAD’s One Health framing recognises the need to look at health, disease, and the environment together, while always taking a given region’s socio-economic, political, and policy context into account.
Cross-neutralising antibodies to SARS-CoV-2 in sera from straw-coloured fruit bats (Eidolon helvum) in Nigeria
Goharriz, Hooman; Wu, Guanghui; Ameh, Veronica O.; Seekings, Amanda H.; Amaya-Cuesta, Joan; McElhinney, Lorraine M.; Sabeta, Claude Taurai (BioMed Central, 2025-08-29)
BACKGROUND : Straw-coloured fruit bats (Eidolon helvum) are widely distributed in Africa and are known reservoirs for viruses with zoonotic potential. These bats are widely hunted in West and Central Africa for human consumption as food source and medicine. This practice increases the potential for spillover of zoonotic disease to the human population. This study investigated the presence of neutralising antibodies against SARS-CoV-2 variants in serum samples (n = 142) from E. helvum bats captured between November 2017 and March 2019 in Makurdi, Nigeria. Faecal samples (n = 120) from the roost were collected in 2022 and screened for the presence of coronavirus RNA followed by genetic sequencing. RESULTS : Virus neutralisation tests revealed 7.04% of the bat sera neutralised 2019-nCoV/Italy-INMI1, while 17.57% of the bat sera neutralised a SARS-CoV-2 Omicron BA.1 isolate. Partial genome obtained by next generation sequencing identified a lineage D Betacoronavirus from one faecal sample with 98.16% nucleotide sequence identity to sequences from Eidolon helvum collected in Cameroon in 2013. Epitope analysis of the spike protein sequence from the faecal sample showed conserved antigenic determinants shared with SARS-CoV-2. CONCLUSIONS : This study demonstrated that pre-pandemic sera collected from Eidolon helvum bats had neutralising activity against SARS-CoV-2 variants. Furthermore we detected the presence of lineage D betacoronavirus in this bat population that shared epitopes with SARS-CoV-2. This work contributes to our understanding of the complexities of coronavirus cross-reactivity. Characterizing bat coronaviruses is crucial to understand their zoonotic potential for spillover events due to bushmeat hunting practices.
Population genetic analysis of Aedes aegypti reveals evidence of emerging admixture populations in coastal Kenya
Mulwa, Francis; Balcazar, Dario; Langat, Solomon; Mutisya, James; Chelangat, Betty; McBride, Carolyn S.; Rose, Noah; Powell, Jeffrey; Sang, Rosemary; Bastos, Armanda D.S.; Gloria-Soria, Andrea; Lutomiah, Joel (Public Library of Science, 2025-05)
BACKGROUND : The Aedes aegypti mosquito is widespread in tropical and subtropical regions. There are two recognized subspecies; the invasive Aedes aegypti aegypti (Aaa) and the ancestral Aedes aegypti formosus (Aaf). Aaf is common throughout Kenya whereas Aaa, which was historically confined to coastal regions, has undergone a range expansion. In areas of sympatry, gene flow may lead to admixed populations with potential differences in vectorial capacity. We hypothesize that coastal Ae. aegypti populations have a higher proportion of Aaa ancestry than those from inland locations of Kenya, influenced by their distance to the coast. METHODOLOGY : Adult Ae. aegypti mosquitoes were collected using Biogent (BG) sentinel traps baited with carbon-dioxide (CO2) from cities and towns along the Kenyan northern transport corridor. Aedes aegypti population structure, genetic diversity, and isolation by distance were analyzed using genome-wide single nucleotide polymorphism (SNPs) datasets generated with an Ae. aegypti microarray chip targeting ≈50,000 SNPs. Kenyan Aedes aegypti populations were placed into a global context within a phylogenetic tree, by combining the Kenyan dataset with a previously published global database. RESULTS : A total of 67 Ae. aegypti mosquitoes population from Kenya were genotyped, we found that western Kenya Ae. aegypti constitute a genetically homogenous population that clusters with African Aaf, whereas coastal mosquitoes showed evidence of admixture between the two subspecies. There was a positive correlation (Observation = 0.869, p = 0.0023) between genetic distance (FST) and geographic distance, suggesting isolation by distance. The phylogenetic analysis and the genetic structure analysis suggest that an Asian Aaa population is the source of Aaa invasion into Kenya. CONCLUSIONS : These results provide evidence of an emerging admixed population of Ae. aegypti in coastal Kenya between the sylvatic Aaf and the domesticated-human preferring Aaa. The observed gene flow from Aaa into Kenya may positively influence Ae. aegypti vectorial capacity, potentially increasing human feeding preference, biting rates and vector competence and could be promoting the observed dengue and chikungunya outbreaks. AUTHOR'S’ SUMMARY Aedes aegypti is of great public health concern due the viruses they transmit. The vector is highly invasive and is expanding to new geographic regions, quickly adapting to new environment. This study focuses in understanding the genetic structure of Ae. aegypti in cities along the northern transport corridor in Kenya, which are at risk of vector invasion. We analyzed Ae. aegypti populations using a panel of Single Nucleotide Polymorphism (SNPs) markers distributed across the genome. Our analysis shows admixture population in the coastal region between Aaf and Aaa, with Asian mosquitos being the putative source of Aaa ancestry, while the western populations are more related to African Aaf. This research provides a broad picture of the nature and dynamics of the Ae. aegypti populations across Kenya and sets the bases for further genetic studies focused on improving vector control strategies and developing novel mosquito control methods.
Biosecurity practices and their determining factors in commercial layer chickens in selected regions of Tanzania
Mdemu, Siha; Matondo, Augustine B.; Christensen, Jens Peter; Amasha, Ahmed E.; Ngowi, Helena Aminiel; Westwood, Erica; Ochai, Sunday Ochonu; Nonga, Hezron Emmanuel; Osbjer, Kristina; Mdegela, Robinson Hammerthon (BioMed Central, 2025-10)
INTRODUCTION : Biosecurity measures are crucial for controlling infectious diseases in poultry farms. It involves all measures aiming at preventing disease-causing agents from entering the farm (external biosecurity) and those measures practiced with the aim of preventing the spread of disease-causing organisms within the farm (internal biosecurity). However, their implementation is often limited in low-income countries due to various factors such as socioeconomic challenges, farming practices and limited resources. The aim of this study was to explore the current biosecurity levels and their related factors in commercial layer chicken farms. METHODS : We conducted a cross-sectional survey of 203 randomly selected commercial layer farms with ≥ 200 birds across Dar es Salaam (n = 154), Morogoro (n = 28), and Unguja (n = 21) regions from March-June 2023. Biosecurity practices were scored using an adapted Biocheck.UGent™ tool (0-100 scale). One-way Analysis of Variance (ANOVA) and t-tests were used for comparing biosecurity scores across groups when data met normality assumptions, while the non-parametric Kruskal-Wallis (K-W) H test and Mann-Whitney (M-W) test served as alternatives when the normality assumption was not met. Further, we used multiple linear regression to identify factors associated with biosecurity implementation; with results reported as standardized beta coefficients (β) and 95% confidence intervals. RESULTS : Mean biosecurity scores were significantly (p < .001) below global benchmarks with overall biosecurity 58.2 ± 8.6, external biosecurity (preventing disease entry) at 60.5 ± 8.7 and internal biosecurity (preventing disease spread within the farm) at 52.9 ± 14.5 compared to global averages of 72%, 67% and 77% respectively. The average external biosecurity scores was significantly lower in farms supervised by farmers with primary education (57.8 ± 7.9) than both those under farmers with secondary education (61.3 ± 9.3, p = .042) and tertiary education (62.1 ± 8.2, p = .019). Farm experience of > 2 years significantly improved internal biosecurity practices (55.0 ± 14.6 vs. 47.0 ± 12.9, p = .002). Further, large-scale operations demonstrated superior internal biosecurity compared to small-scale farms (63.1 ± 16.4 vs. 51.5 ± 12.8, p = .002). Multiple regression analysis (F₇,₁₉₅=2.279, p = .030, R²=0.076) revealed that secondary education (β = 0.224, 95% CI: 1.03–6.73, p = .007) and tertiary education (β = 0.209, 95% CI: 0.82–7.20, p = .014) were independently associated with higher biosecurity scores compared to primary education. CONCLUSION : This paper provides the first assessment of biosecurity implementation in commercial layer farms in Tanzania comparing it with global benchmarks. Biosecurity implementations were largely influenced by three key factors; education level, scale of production, and farming experience. These findings indicate that tailored interventions and evidenced-based policies are essential for strengthening biosecurity practices, and potentially enhancing poultry health and productivity in layer farms.
Knowledge, attitudes and practices of communal goat farmers on the prevalence and control of gastrointestinal nematodes in northern KwaZulu-Natal, South Africa
Ndwandwe, Khanyisani Cyril; Chimonyo, Michael; Tsotetsi-Khambule, Ana Mbokeleng; Marufu, Munyaradzi Christopher (Wiley, 2025-07)
Gastrointestinal nematodes (GINs) are a significant impediment to communal goat production, causing considerable economic losses, making their control imperative. The objective of this study was to determine farmers’ knowledge, attitudes and practices on the control of GIN in communal goat flocks. A structured close-ended questionnaire was used to conduct face-to-face interviews with communal goat farmers (n = 384) across four local municipalities in uMkhanyakude District Municipality. Elderly farmers were 1.4 times more likely to underdose compared to younger farmers (p < 0.05). Diarrhoea and emaciation were the most reported clinical signs observed in goat flocks. Farmers were aware of clinical signs of GIN infections (p < 0.01) on their farms. However, lack of professional veterinary assistance (p < 0.01), low socioeconomic status and low levels of education (p < 0.01) reduce the effectiveness of GIN control. Farmer’s inability to read manufacturer’s instructions was associated with incorrect dosing (p < 0.05), which contributed to ineffective management and worsened the impacts of GIN infections. An immediate intervention is required from various stakeholders to achieve sustainable nematode control, with a particular emphasis on women, the elderly farmers and those with low levels of education.
Decision support system for Lespedeza cuneata production and quality evaluation : a WebGIS dashboard approach to precision agriculture
Panda, Sudhanshu S.; Siddique, Aftab; Terrill, Thomas H.; Mahapatra, Ajit K.; Morgan, Eric; Pech-Cervantes, Andres A.; Van Wyk, Jan Aucamp (Frontiers Media, 2025-07-17)
Small-scale farmers in the southeastern United States face increasing challenges in sustaining forage production due to erratic rainfall, poor soils, and limited access to precision agricultural tools. These constraints demand site-specific solutions that integrate climate resilience with sustainable land use. This study introduces a pioneering Site-Specific Fodder Management Decision Support System (SSFM-DSS) designed to optimize the cultivation of Lespedeza cuneata (sericea lespedeza), a drought-tolerant, nitrogen-fixing legume well-suited for marginal lands. By integrating high-resolution geospatial technologies—Geographic Information Systems (GIS), Global Navigation Satellite Systems (GNSS), and remote sensing—with empirical field data and predictive modeling, we have developed an automated suitability framework for SL cultivation across Alabama, Georgia, and South Carolina. The model incorporates multi-criteria environmental parameters, including soil characteristics, topography, and climate variability, to generate spatially explicit recommendations. To translate these insights into actionable strategies, we also developed a farmer-focused WebGIS Dashboard that delivers real-time, location-based guidance for SL production. Our findings underscore the significant potential of SSFM-DSS to enhance fodder availability, improve system resilience under climate stress, and promote sustainable livestock production. This integrative approach offers a promising pathway for climate-smart agriculture, supporting broader food security objectives in vulnerable agroecosystems.
In vitro characterization of the E. ruminantium pLAMP multi-epitope DNA poly (lactic-co-glycolic acid) nanoparticle vaccine in sheep peripheral blood mononuclear cells
Nesane, Mashudu; Pretorius, Alri; Van Wyngaardt, Wouter; Tshilwane, Selaelo Ivy; Faber, Frederika E.; Steyn, H.; Lemmer, Y.; Van Kleef, Mirinda; Thema, Nontobeko (Elsevier, 2025-08)
Heartwater is a tick-borne disease caused by Ehrlichia ruminantium, that has a major economic impact on smallholder farmers. This study investigates the potential of Poly Lactic-co-Glycolic Acid (PLGA) nanoparticles (NPs) as a delivery system for the pLAMP multi-epitope DNA vaccine against heartwater. The vaccine was designed to enhance antigen presentation and activation of specific immune responses, including CD4 + and CD8 + T cell activation. Spherical microspheres with smooth surfaces ranging from 180 nm to 5 µm in diameter were produced, with an adsorption efficiency of 83 %. The in vitro release kinetics demonstrated an initial release of adsorbed pLAMP DNA from PLGA NPs peaking at day 7 and again at day 35. Cellular uptake and gene expression were confirmed using the Vitality hrGFP II plasmid that was adsorbed onto PLGA NPs. High throughput transcriptome sequencing was utilized to determine the immune response activated by the vaccine in vitro in immune sheep peripheral blood mononuclear cells (PBMCs). The pLAMP plasmid transcripts were shown to be present, and key immune pathways, including DNA sensing pathways, MHC presentation and CD4 + T cell and CD8 + T cell pathways were activated that corresponded to those identified and used for the vaccine design previously. This is an indication of the capability of the pLAMP-NP vaccine to induce the desired immune responses, demonstrating potential for in vivo studies. HIGHLIGHTS • The pLAMP DNA vaccine was adsorbed to PLGA nano particles showing controlled release kinetics. • RNA-seq data confirmed treatment-specific immune pathway activation in heartwater immune sheep PBMC. • The pLAMP-nano vaccine induced a similar vaccine immune response as was previously reported in vivo.
Advancing disease surveillance in rhinoceroses : a multiplex real-time PCR assay for detecting Theileria bicornis and Babesia bicornis
Sekgobela, Naledi Palesa Brilliantine; Vorster, Ilse; Troskie, Milana; Troskie, Milana; Quan, Melvyn; Zimmerman, David E.; Hassim, Ayesha; Neves, Luís C.B.G.; Bhoora, Raksha Vasantrai (Elsevier, 2025-11)
Black (Diceros bicornis) and white (Ceratotherium simum) rhinoceroses in Southern Africa face multiple threats, including poaching, habitat loss, and translocation stress. Infections with Theileria bicornis (in both rhino species) and Babesia bicornis (confirmed only in black rhinos) add further health risks, with stressors such as translocation potentially increasing susceptibility. Effective management requires sensitive molecular diagnostic assays for accurate detection and surveillance. To address this, we developed a multiplex qPCR assay (MqTbBb) using species-specific TaqMan™ minor groove binder (MGB) probes for the simultaneous detection of T. bicornis and B. bicornis. The assay targets 18S rRNA gene regions, amplifying an 87 bp fragment for T. bicornis and a 51 bp fragment for B. bicornis, with efficiencies of 100 % and 98 %, respectively. Probit analysis determined a 95 % Limit of detection of 1.00 × 10⁻⁶ % and 6.27 × 10⁻⁶ % equivalent parasitized erythrocytes for T. bicornis and B. bicornis, respectively. No cross-reactivity was observed with other related protozoa tested. A total of 223 field samples from rhinos (101 black and 122 white) in Mpumalanga province were screened using both the MqTbBb and Reverse Line Blot (RLB) hybridization assays. The MqTbBb detected T. bicornis in 57 % of black and 99 % of white rhinos, with co-infections in 40 % of black rhinos. RLB detected T. bicornis in 96 % of black and 95 % of white rhinos, with a Babesia catch-all probe signal in 75 % and 32 %, respectively. B. bicornis was not detected by RLB and was never detected as a single infection by qPCR. These findings highlight high T. bicornis prevalence and rare B. bicornis infections (co-infections). The MqTbBb assay strengthens detection, surveillance, and conservation efforts.
Detection of tick-borne pathogen coinfections and coexposures to foot-and-mouth disease, brucellosis, and Q fever in selected wildlife from Kruger National Park, South Africa, and Etosha National Park, Namibia
Cossu, Carlo Andrea; Ochai, Sunday Ochonu; Troskie, Milana; Hartmann, Axel; Godfroid, Jacques; De Klerk, Lin-Mari; Turner, Wendy C.; Kamath, Pauline; Van Schalkwyk, Ockert Louis; Cassini, Rudi; Bhoora, Raksha Vasantrai; Van Heerden, Henriette (Wiley, 2024-12-12)
BACKGROUND : Although the rate of emerging infectious diseases that originate in wildlife has been increasing globally in recent decades, there is currently a lack of epidemiological data from wild animals. METHODOLOGY : We used serology to determine prior exposure to foot-and-mouth disease virus (FMDV), Brucella spp., and Coxiella burnetii and used genetic testing to detect blood-borne parasitic infections in the genera Ehrlichia, Anaplasma, Theileria, and Babesia from wildlife in two national parks, Kruger National Park (KNP), South Africa, and Etosha National Park (ENP), Namibia. Serum and whole blood samples were obtained from free-roaming plains zebra (Equus quagga), greater kudu (Tragelaphus strepsiceros), impala (Aepyceros melampus), and blue wildebeest (Connochaetes taurinus). Risk factors (host species, sex, and sampling park) for infection with each pathogen were assessed, as well as the prevalence and distribution of co-occurring infections. RESULTS : In KNP 13/29 (45%; confidence interval [CI]: 26%–64%) kudus tested positive for FMD, but none of these reacted to SAT serotypes. For brucellosis, seropositive results were obtained for 3/29 (10%; CI: 2%–27%) kudu samples. Antibodies against C. burnetii were detected in 6/29 (21%; CI: 8%–40%) kudus, 14/21 (67%; CI: 43%–85%) impalas, and 18/39 (46%; CI: 30%–63%) zebras. A total of 28/28 kudus tested positive for Theileria spp. (100%; CI: 88%–100%) and 27/28 for Anaplasma/Ehrlichia spp. (96%; CI: 82%–100%), whereas 12/19 impalas (63%) and 2/39 zebra (5%) tested positive for Anaplasma centrale. In ENP, only 1/29 (3%; CI: 0%–18%) wildebeest samples tested positive for FMD. None of the samples tested positive for brucellosis, while C. burnetii antibodies were detected in 26/30 wildebeests (87%; CI: 69%–96%), 16/40 kudus (40%; CI: 25%–57%), and 26/26 plains zebras (100%; CI: 87%–100%). A total of 60% Anaplasma/Ehrlichia spp. and 35% Theileria/Babesia spp. in kudu and 37% wildebeest tested positive to Theileria sp. (sable), 30% to Babesia occultans, and 3%–7% to Anaplasma spp. The seroprevalence of Q fever was significantly higher in ENP, while Brucella spp., Anaplasma, Ehrlichia, Theileria, and Babesia species were significantly higher in KNP. Significant coinfections were also identified. CONCLUSION : This work provided baseline serological and molecular data on 40+ pathogens in four wildlife species from two national parks in southern Africa.
Genetic variability in snake venom and its implications for antivenom development in sub-Saharan Africa
Ayesiga, Innocent; Okoro, Lenz N.; Taremba, Chirigo; Yeboah, Michael O.; Naab, Justine T.M.; Anyango, Ruphline M.; Adekeye, John; Kahw, Ivan (Oxford University Press, 2025-04)
Snake venom, a complex mixture of proteins, has attracted human attention for centuries due to its associated mortality, morbidity and other therapeutic properties. In sub-Saharan Africa (SSA), where snakebites pose a significant health risk, understanding the genetic variability of snake venoms is crucial for developing effective antivenoms. The wide geographic distribution of venomous snake species in SSA countries demonstrates the need to develop specific and broad antivenoms. However, the development of broad antivenoms has been hindered by different factors, such as antivenom cross-reactivity and polygenic paratopes. While specific antivenoms have been hindered by the numerous snake species across the SSA region, current antivenoms, such as SAIMR polyvalent and Premium Serums & Vaccines, exhibit varying degrees of cross-reactivity. Such ability to cross-react enables the antivenoms to target multiple components from the different snake species. The advent of biotechnological innovations, including recombinant antibodies, small-molecule drugs, monoclonal antibodies and synthetic antivenoms, presents options for eliminating limitations associated with traditional plasma-derived antivenoms. However, challenges still persist, especially in SSA, in addressing genetic variability, as evidenced by inadequate testing capacity and limited genomic research facilities. This comprehensive review explores the genetic variability of snake venoms in SSA, emphasizing the venom composition of various snake species and their interactions. This information is critical in developing multiple strategies during antivenom development. Finally, it offers information concerning the need for extensive collaborative engagements, technological advancements and comprehensive genomic evaluations to produce targeted and effective antivenoms.
Quantitative detection of Theileria haneyi in South African horses
Bhoora, Raksha Vasantrai; Mbaba, Tshenolo Vincentia; Troskie, Milana; Ackermann, Rebecca; Collins, Nicola E. (Elsevier, 2025-05)
Theileria haneyi is an apicomplexan parasite closely related to Theileria equi, a known causative agent of equine piroplasmosis. The molecular distinction between these parasites relies on a nested polymerase chain reaction (PCR) assay, which has been reported to be unreliable. A recently reported indirect ELISA based on equi merozoite antigen 11 (Thema-11) of T. haneyi can detect geographically diverse T. haneyi strains. Since the ema-11 gene is exclusive to T. haneyi, it was chosen as the target for developing a TaqMan minor groove binder (MGB™) quantitative real-time PCR (qPCR). Published T. haneyi ema-11 gene sequences were used to design primers to amplify the ema-11 gene, and ema-11 amplicons from South African samples were cloned and sequenced. An alignment of the South African ema-11 gene sequences with published T. haneyi ema-11 gene sequences enabled the identification of a conserved region for the design of the qPCR assay. The T. haneyi ema-11 (Thema-11) qPCR assay was efficient, specific, and sensitive in detecting T. haneyi ema-11. The detection limit was determined to be 1.169 × 10–3 % parasitized erythrocytes. The performance of the Thema-11 qPCR assay was evaluated together with a T. equi ema-1-specific qPCR assay. Theileria haneyi was detected in 67.6 % of the South African field samples screened, while the occurrence of T. equi based on the quantitative amplification of the ema-1 gene was higher (91.8 %). Our results suggest that combined, the Thema-11 and T. equi ema-1 qPCR assays could detect and differentiate between T. haneyi and T. equi infections. HIGHLIGHTS • Theileria haneyi ema-11 sequences form two clades. • A TaqMan quantitative real-time PCR (qPCR) assay was developed to detect T. haneyi. • The Thema-11 and T. equi ema-1 qPCR assays detect and differentiate between T. haneyi and T. equi infections. • Mixed T. haneyi and T. equi infections are common in South Africa. • Theileria haneyi is always detected in samples that test positive for genotype C.
Demonstrating persistence of foot-and-mouth disease virus in African buffalo (Syncerus caffer) using BaseScope™ in situ hybridisation
Henning, Alischa; Odendaal, Lieza; Loots, Angelika Katrin; Quan, Melvyn (Springer, 2025-09-23)
BaseScope™ in situ hybridisation (Advanced Cell Diagnostics, USA) was used to detect foot-and-mouth disease virus (FMDV), species Aphthovirus vesiculae, in formalin-fixed paraffin-embedded tissues from African buffalo (Syncerus caffer, n = 15) culled from the Kruger National Park - where the South African territories (SAT)-1, -2 and - 3 serotypes are endemic - as part of their population management program. Foot-and-mouth disease viral RNA was consistently detected in the palatine tonsils and lungs, demonstrating these as primary sites of viral persistence. Detection in the retropharyngeal lymph nodes and interdigital skin was less frequent, while oropharyngeal tissue showed rare positivity. Other sampled tissues - including the tip of the ear, eyelid, tongue, lip, and coronary band - proved suboptimal for identifying FMDV-positive buffalo or carriers. These findings highlight the value of BaseScope™ for detecting low viral loads of FMDV in persistently infected African buffalo, with a notable predilection for the palatine tonsils and lungs.
Occurrence of tick-borne haemoparasites in South African rodent species evidence of Babesia microti-like sequence variants in two Rhabdomys species
Troskie, Milana; Matthee, Sonja; Penzhorn, Barend Louis; Jansen, Raymond; Oosthuizen, Marinda C. (Elsevier, 2025-04)
In recent years, vector-borne viral, bacterial and parasitic diseases have emerged or re-emerged in many geographic regions, causing health and economic problems. Wildlife can act as reservoirs for many human and livestock diseases and that arthropods are often involved in the transmission of these pathogens. Little is known about the zoonotic pathogens that naturally occur in wild rodent and insectivorous shrew species in South Africa. The aims of the study were to: 1) record the tick-borne haemoparasite diversity associated with rodents and shrews at several localities in South Africa, and 2) characterise Babesia microti that occur in rodents using Sanger sequencing of the parasite 18S ribosomal RNA (rRNA) gene and internal transcribed spacer region 1 (ITS1). Nine wild rodent genera (species: n = 412) and two insectivorous shrew genera (species: n = 11) were simultaneously screened for the presence of Theileria, Babesia, Ehrlichia and Anaplasma species using the Reverse Line Blot (RLB) hybridization assay. The RLB PCR amplicons obtained from Mastomys spp., Micaelamys namaquensis, Mus musculus, Rhabdomys dilectus and R. pumilio hybridized with the following RLB species-specific probes: Babesia microti (11.3%), Anaplasma bovis (3.5%), Anaplasma phagocytophilum (1.8%) and Ehrlichia ruminantium (3.5%). The near full-length 18S rRNA gene and partial ITS1 spacer region of 12 of the specimens were cloned and the recombinants sequenced. Babesia microti-like 18S rDNA and ITS1 sequence variants were recorded in two rodent species (Rhabdomys dilectus and Rhabdomys pumilio). The B. microti-like 18S rDNA sequence variants, obtained in this study, clustered phylogenetically within the established B. microti-like clade (Clade I). Nevertheless, they formed a distinct South African group that seems to differ significantly from B. microti sensu stricto and could potentially represent a fifth distinct lineage within the B. microti-like clade.The study highlights the potential of small mammals acting as important reservoirs for vector-borne haemoparasites in South Africa. HIGHLIGHTS • Most extensive study on haemoparasites associated with small mammals in Southern Africa to date. • 63.3% rodent samples positive for Theileria/Babesia/Ehrlichia/Anaplasma DNA. • Regional-specific Babesia microti-like sequence variants recorded in two commensal and wide-spread rodent species.
Infection rates of Fasciola spp. in cattle slaughtered at 13 abattoirs in six of nine provinces of South Africa
Nukeri, Sophy; Malatji, Mokgadi Pulane; Sithole, Msawenkosi I.; Ngcamphalala, Philile I.; Nyagura, Ignore; Tembe, Danisile; Ndlovu, Innocent Siyanda; Chaisi, Mamohale E.; Mukaratirwa, Samson (Elsevier, 2025-06)
Fasciolosis or liver fluke infection is a snail-borne disease that affects the productivity of domestic ruminants including liver condemnation especially in cattle. However, there is paucity of information on the burden of infection due to lack of accurate data on liver condemnation related to correct geographical origin of infected animals. This distorts perception of the geographical occurrence of fasciolosis, particularly in South Africa among other countries. We aimed to determine the infection rates of Fasciola spp. in cattle slaughtered at selected abattoirs in South Africa. A total of 13 abattoirs consisting of 10 high throughput and three low throughput abattoirs across six provinces, were visited to screen for liver fluke infection in slaughtered cattle including tracing of the animals' geographical origin. A total of 57 livers from 673 slaughtered cattle (8.5 %) from 10 abattoirs were infected with Fasciola spp.. The highest infection rate from the study sites was 37 % and the lowest 4.5 %. Tracing of infected cattle showed that some abattoirs slaughtered cattle originating from other provinces. Forty-nine percent (29/57) of infected cattle had moderate body condition score (BCS) and recorded the highest intensity of fluke infection (>100 flukes per liver). Furthermore, young animals had high infection rates (51 %; 29/57) compared to adults (49 %; 28/57) and females (54 %; 31/57) compared to males (46 %; 26/57). The overall results highlighted the presence of Fasciola spp. in five provinces of South Africa, represented by more than four agro-ecological zones. Fasciola hepatica occurred in all six provinces while both Fasciola spp. co-occurred in one province. Furthermore, F. hepatica constituted the highest percentage (74 %; 710/960) of Fasciola spp. specimens collected. Fasciola gigantica were collected from abattoirs in one province and constituted 26 % (250/960) of the total collected flukes. Results from the study provide information on the burden of fasciolosis in cattle. This is based on abattoir surveys in South Africa, considering the traced geographical origin of animals slaughtered. Using data from surveys of this nature might support efforts to map the geographical distribution of fasciolosis in South Africa. Thus, contribute towards the development of effective control and treatment programs of fasciolosis to mitigate the burden of the disease in cattle. HIGHLIGHTS • Fasciolosis is prevalent in cattle slaughtered at abattoirs from six provinces of South Africa. • Cattle movement for slaughter distorts the true prevalence at provincial level. • Cattle movement may contribute to introduction of infections to new areas. • Fasciola hepatica was recorded in all six provinces. • Fasciola gigantica co-occurred with F. hepatica in the Limpopo province.
Temporal changes in the bacterial microbiome of the salivary gland and midgut tissues of Rhipicephalus sanguineus (s.l.) ticks in South Africa
Ackermann, Rebecca; Gall, Cory A.; Brayton, Kelly A.; Collins, Nicola E.; Van Wyk, Ilana; Wentzel, Jeanette; Kolo, Agatha O,; Oosthuizen, Marinda C. (Nature Research, 2025-05)
Tick-borne bacterial pathogens from animals play a significant role in the (re)emergence of human diseases. Rhipicephalus sanguineus sensu lato, a globally prevalent tick, predominantly parasitises domestic dogs but can also feed on humans. We characterised temporal changes in the bacterial microbiome of the midgut and salivary gland tissues of R. sanguineus s.l. ticks and analysed their potential as reservoirs for pathogenic bacteria. A 16 S microbiome and amplicon sequence variant (ASV) approach was used to study the bacteria present in the tissues of R. sanguineus s.l. ticks collected from dogs in Hluvukani, a village in a rural community in Bushbuckridge, Mpumalanga, South Africa, in 2016, 2017 and 2019. Post processing, we obtained 43,161 total sequence reads which were clustered into ASVs by sample year. The final ASVs dataset consisted of seven genera: Coxiella, Anaplasma, Escherichia/Shigella, Ehrlichia, Borrelia, Rickettsia and Wolbachia. No differences in the microbiome profiles of the MG and SG tissues were noted. Coxiella endosymbionts dominated the microbiome in all years. Anaplasma was first detected in 2017, and an increase in Anaplasma levels was detected in 2019, when compared to 2017. All other genera were present at low levels. With the exclusion of Wolbachia, the other detected genera could have pathogenic potential, highlighting the role that R. sanguineus s.l. might play as a reservoir of pathogens.
Seroprevalence and risk factors associated with Brucellosis in goats in Nyagatare District, Rwanda
Habimana, Jean Paul; Ntivuguruzwa, Jean Bosco; Uwimana, Aime Lambert; Ugirabe, Marie Aurore; Gasana, Eric; Van Heerden, Henriette (Wiley, 2025-08)
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
Motloung, R.F.; Chaisi, Mamohale E.; Sibiya, M.S.; Nyangiwe, N.; Shivambu, T.C. (Elsevier, 2025-08)
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
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 (Elsevier, 2025-08)
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)
Griessel, Theunis Steyn; Moran, Juan Alberto Munoz; Byaruhanga, Charles; Smit, Yolandi (Wiley, 2025-05)
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.

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