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West Nile virus infection of Thoroughbred horses in South Africa (2000-2001).
Abstract: West Nile virus (WNV) infection is endemic in southern Africa. With the recent emergence of WNV infection of horses in Europe and the USA the present study was performed to estimate the risk of seroconversion to WNV in a cohort of 488 young Thoroughbred (TB) horses. Objective: To estimate the risk of seroconversion to WNV among a cohort of South African TB yearlings sold at the 2001 National Yearling Sales (NYS) and to determine whether the risk varied geographically. Two horses were also infected with a recent South African isolate of WNV to evaluate its virulence in horses. Methods: Serum samples were collected from the cohort of 488 TB yearlings at the 2001 NYS. Serum samples that were collected from the same horses at the time that they were identified were sourced from our serum bank. Sera from 243 of the dams that were collected at the time that the foals were identified were also sourced from our serum bank. These sera were subjected to serum neutralisation (SN) tests for antibody to WNV. Results: Approximately 11% of yearlings seroconverted to WNV on paired serum samples collected from each animal approximately 12 months apart. Studfarms with WNV-seropositive yearlings were widely distributed throughout South Africa and SN tests on sera from their dams indicated that exposure to WNV was even more prevalent (75%) in this population. Neurological disease was not described in any of the horses included in this study and 2 horses inoculated with a recent lineage 2 South African isolate of WNV showed no clinical signs of disease after infection and virus was not detected in their blood. Conclusions: Infection of horses with WNV is common in South Africa, but infection is not associated with neurological disease. Conclusions: In contrast to recent reports from Europe, North Africa, Asia and North America, the results of our field and experimental studies indicated that exposure of horses to the endemic southern African strains of WNV was not associated with neurological disease.
Publication Date: 2003-10-01 PubMed ID: 14515962DOI: 10.2746/042516403775467180Google Scholar: Lookup The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
The research is about the West Nile Virus (WNV) infection in Thoroughbred horses in South Africa and the effects of the infection in these horses compared to other geographic locations. The study found that while WNV infection is common among these horses, it does not cause neurological disease.
Objective and Methodology
They aimed to estimate the probability of Thoroughbred yearlings developing an immune response, or seroconversion, to WNV and how this may vary geographically. Further, they infected two horses with a recent South African WNV strain to assess its virulence.
- Blood samples were collected from a group of 488 Thoroughbred yearlings at the 2001 National Yearling Sales event.
- These samples, along with additional samples kept in their serum bank taken when the horses were first identified, were tested for antibodies against WNV using serum neutralization tests.
- Similar tests were performed on blood samples taken from 243 dams (mothers of the Thoroughbreds) at the time their foals were identified.
Results
The results showed that around 11% of yearlings displayed an immune response to the WNV. The horses’ origins were spread throughout South Africa, suggesting WNV exposure is widespread. Importantly, their dams indicated even higher exposure rates, at 75%.
- Notably, none of the infected horses exhibited signs of neurological disorders, a key trait of WNV.
- Furthermore, the two horses inoculated with the recent South African WNV strain didn’t show clinical signs of disease or detectable virus in their blood.
Conclusions
The study concludes that while WNV infection is prevalent among Thoroughbreds in South Africa, it does not result in the same neurological disease observed in other regions such as Europe, North Africa, Asia, and North America.
- The absence of neurological symptoms in the Thoroughbreds and the two horses intentionally infected suggests that the South African strain of the virus might manifest itself differently from the ones found in other regions.
Cite This Article
APA
Guthrie AJ, Howell PG, Gardner IA, Swanepoel RE, Nurton JP, Harper CK, Pardini A, Groenewald D, Visage CW, Hedges JF, Balasuriya UB, Cornel AJ, MacLachlan NJ.
(2003).
West Nile virus infection of Thoroughbred horses in South Africa (2000-2001).
Equine Vet J, 35(6), 601-605.
https://doi.org/10.2746/042516403775467180 Publication
Researcher Affiliations
- Equine Research Centre, Faculty of Veterinary Science, University of Pretoria, Onderstepoort 0110, South Africa.
MeSH Terms
- Animals
- Antibodies, Viral / blood
- Cohort Studies
- Female
- Horse Diseases / blood
- Horse Diseases / epidemiology
- Horses
- Male
- Neutralization Tests / veterinary
- Phylogeny
- Risk Factors
- South Africa / epidemiology
- Virulence
- West Nile Fever / blood
- West Nile Fever / epidemiology
- West Nile Fever / veterinary
- West Nile virus / immunology
- West Nile virus / isolation & purification
- West Nile virus / pathogenicity
Citations
This article has been cited 14 times.- Mencattelli G, Ndione MHD, Rosà R, Marini G, Diagne CT, Diagne MM, Fall G, Faye O, Diallo M, Faye O, Savini G, Rizzoli A. Epidemiology of West Nile virus in Africa: An underestimated threat. PLoS Negl Trop Dis 2022 Jan;16(1):e0010075.
- Srihi H, Chatti N, Ben Mhadheb M, Gharbi J, Abid N. Phylodynamic and phylogeographic analysis of the complete genome of the West Nile virus lineage 2 (WNV-2) in the Mediterranean basin. BMC Ecol Evol 2021 Sep 27;21(1):183.
- Conze TM, Bagó Z, Revilla-Fernández S, Schlegel J, Goehring LS, Matiasek K. Tick-Borne Encephalitis Virus (TBEV) Infection in Two Horses. Viruses 2021 Sep 6;13(9).
- Olufemi OT, Barba M, Daly JM. A Scoping Review of West Nile Virus Seroprevalence Studies among African Equids. Pathogens 2021 Jul 15;10(7).
- Molini U, Franzo G, Nel H, Khaiseb S, Ntahonshikira C, Chiwome B, Baines I, Madzingira O, Monaco F, Savini G, D'Alterio N. West Nile Virus Seroprevalence in a Selected Donkey Population of Namibia. Front Vet Sci 2021;8:681354.
- Alzuheir I, Fayyad A, Jalboush N, Abdallah R, Abutarbush S, Gharaibeh M, Bdarneh M, Khraim N, Helal MA, Helal BA. Seroprevalence and risk factors of West Nile virus infection in veterinarians and horses in Northern Palestine. Vet World 2021 May;14(5):1241-1246.
- Bertram FM, Thompson PN, Venter M. Epidemiology and Clinical Presentation of West Nile Virus Infection in Horses in South Africa, 2016-2017. Pathogens 2020 Dec 30;10(1).
- Sule WF, Oluwayelu DO, Hernández-Triana LM, Fooks AR, Venter M, Johnson N. Epidemiology and ecology of West Nile virus in sub-Saharan Africa. Parasit Vectors 2018 Jul 13;11(1):414.
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- Venter M, Human S, Zaayman D, Gerdes GH, Williams J, Steyl J, Leman PA, Paweska JT, Setzkorn H, Rous G, Murray S, Parker R, Donnellan C, Swanepoel R. Lineage 2 west nile virus as cause of fatal neurologic disease in horses, South Africa. Emerg Infect Dis 2009 Jun;15(6):877-84.
- Kuno G, Chang GJ. Biological transmission of arboviruses: reexamination of and new insights into components, mechanisms, and unique traits as well as their evolutionary trends. Clin Microbiol Rev 2005 Oct;18(4):608-37.
- Naveed A, Eertink LG, Wang D, Li F. Lessons Learned from West Nile Virus Infection:Vaccinations in Equines and Their Implications for One Health Approaches. Viruses 2024 May 14;16(5).
- Ben-Mostafa KK, Savini G, Di Gennaro A, Teodori L, Leone A, Monaco F, Alaoqib MMA, Rayes AA, Dayhum A, Eldaghayes I. Evidence of West Nile Virus Circulation in Horses and Dogs in Libya. Pathogens 2023 Dec 31;13(1).
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