West Nile virus infection of Thoroughbred horses in South Africa (2000-2001)
Autor: | P. G. Howell, Ian A. Gardner, D. Groenewald, Nigel J Maclachlan, Udeni B. R. Balasuriya, J. P. Nurton, R. E. Swanepoel, C. W. Visage, Alan John Guthrie, Jodi F. Hedges, Cindy Kim Harper, A. J. Cornel, A. Pardini |
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Rok vydání: | 2010 |
Předmět: |
Male
medicine.medical_specialty Veterinary medicine viruses Population Biology Antibodies Viral Virus Serology Cohort Studies South Africa Neutralization Tests Risk Factors Epidemiology medicine Animals Horses Seroconversion education Phylogeny education.field_of_study Virulence virus diseases Horse General Medicine Virology Cohort Female Horse Diseases West Nile virus West Nile Fever Cohort study |
Zdroj: | Equine Veterinary Journal. 35:601-605 |
ISSN: | 2042-3306 0425-1644 |
Popis: | Summary Reasons for performing study: West Nile virus (WNV) infection is endemic in southern Africa. With the recent emergence of WNV infection of horses in Europe and the USAthe present study was performed to estimate the risk of seroconversion to WNV in a cohort of 488 young Thoroughbred (TB) horses. Objectives: 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 whetherthe 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 ourserum 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 theirdams indicated that exposure to WNVwas 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. Potential relevance: 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. |
Databáze: | OpenAIRE |
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