ORIGINAL RESEARCH

 

Prevalence of serotype specific antibody to equine encephalosis virus in Thoroughbred yearlings in South Africa (1999-2004)

 

 

P.G. Howell; Jane P. Nurton; Daleen Nel; Carina W. Lourens; A.J. Guthrie^*

Equine Research Centre, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110 South Africa

 

 

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ABSTRACT

Cohorts of yearlings were sampled over a period of 6 years in a retrospective serological survey to establish the annual prevalence of serotype specific antibody to equine encephalosis virus on Thoroughbred stud farms distributed within defined geographical regions of South Africa.
Seasonal seroprevalence varied between 3.6 % and 34.7 %, revealing both single and multiple serotype infections in an individual yearling. During the course of this study serotypes 1 and 6 were most frequently and extensively identified while the remaining serotypes 2, 3, 4, 5 and 7 were all identified as sporadic and localized infections affecting only individual horses.
This study of the seasonal prevalence of equine encephalosis virus has a corollary and serves as a useful model in the seasonal incidence of the serotypes of African horse sickness and bluetongue in regions where the respective diseases are endemic.

Keywords: Equine encephalosis virus, horses, neutralizing antibody, orbivirus, prevalence, sero-epidemiology, serotypes

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REFERENCES

BARNARD, B.J.H. 1993. Circulation of African horsesickness virus in zebra (Equus burchelli) in the Kruger National Park, South Africa, as measured by the prevalence of type specific antibodies. Onderstepoort Journal of Veterinary Research, 60:111-117.         [ Links ]

BARNARD, B.J.H. & PAWESKA, J.T. 1993. Prevalence of antibodies against some equine viruses in zebra (Zebra burchelli) in the Kruger National Park, 1991-1992. Onderstepoort Journal of Veterinary Research, 60:175-179.         [ Links ]

CRAFFORD, J.E. 2001. Development and validation of enzyme-linked immunosorbent assays for detection of equine encephalosis virus antibody and antigen. M.Sc. thesis, University of Pretoria.         [ Links ]

DU TOIT, R.M. 1962. The role played by bovines in the transmission of bluetongue in sheep. Journal of the South African Veterinary Medical Association, 33:483-490.         [ Links ]

ERASMUS, B.J., ADELAAR, T.F., SMIT, J.D., LECATSAS, G. & TOMS, T. 1970. The isolation and characterization of equine encephalosis virus. Bulletin de l'Office International des Épizooties, 74:781-789.         [ Links ]

ERASMUS, B.J., BOSHOFF, S.T. & PIETERSE, L.M. 1996. The isolation and characterization of equine encephalosis and serologically related orbiviruses from horses, in Equine infectious diseases IV, edited by J.T. Bryans & H. Gerber. Princeton, New Jersey: Veterinary Publications Incorporated.         [ Links ]

GORMAN, B.M., TAYLOR, J. & WALKER, P.J. 1983. Orbivirus, in The Reoviridae, edited by W.K. Joklik. New York: Plenum Press.         [ Links ]

GUTHRIE, A.J., HOWELL, P.G., GARDNER, I.A., SWANEPOEL, R.E., NURTON, J.P., HARPER, C.K., PARDINI, A., GROENEWALD, D., VISAGE, C.W., HEDGES, J.F., BALASURIYA, U.B., CORNEL, A.J. & MACLACHLAN, N.J. 2003. West Nile virus infection of Thoroughbred horses in South Africa (2000-2001). Equine Veterinary Journal, 35:601-605.         [ Links ]

HOWELL, P.G. 1962. The isolation and identification of further antigenic types of African horsesickness virus. Onderstepoort Journal of Veterinary Research, 29:139-149.         [ Links ]

HOWELL, P.G. 1969. The antigenic classification of strains of bluetongue virus, their significance and use in prophylactic immunization. D.V.Sc thesis, University of Pretoria.         [ Links ]

HOWELL, P.G., GROENEWALD, D.M., VISAGE, C.W., BOS-MAN, A., COETZER, J.A.W. & GUTHRIE, A.J. 2002. The classification of seven serotypes of equine encephalosis virus and the prevalence of homologous antibody in horses in South Africa. Onderstepoort Journal of Veterinary Research, 69:79-93.         [ Links ]

HUISMANS, H. 1979. Protein synthesis in bluetongue virus-infected cells. Virology, 92:385-396.         [ Links ]

HUISMANS, H., VAN DER WALT, N.T., CLOETE, M. & ERASMUS, B.J. 1987. Isolation of a capsid protein of bluetongue virus that induces a protective immune response in sheep. Virology, 157:172-179.         [ Links ]

MCINTOSH, B.M. 1958. Immunological types of horsesickness virus and their significance in immunization. Onderstepoort Journal of Veterinary Research, 27:465-539.         [ Links ]

MEISWINKEL, R., NEVILL, E.M. & VENTER, G.J. 1994. Vectors: Culicoides spp., in Infectious diseases of livestock with special reference to Southern Africa, edited by J.A.W.Coetzer, G.R.Thomson & R.C.Tustin. Cape Town: Oxford University Press.         [ Links ]

NEVILL, E.M. 1971. Cattle and Culicoides biting midges as possible overwintering hosts of bluetongue virus. Onderstepoort Journal of Veterinary Research, 38:65-71.         [ Links ]

PAWESKA, J.T., GERDES, G.H., WOODS, P.S.A. & WILLIAMS, R. 1999. Equine encephalosis in southern Africa: Current situation, in Equine infectious diseases VIII, edited by U. Wernery, J.F. Wade, J.A. Mumford & O.R. Kaaden. Newmarket: R & W Publications (Newmarket) Ltd.         [ Links ]

SCANLEN, M., PAWESKA, J.T., VERSCHOOR, J.A. & VAN DIJK, A.A. 2002. The protective efficacy of a recombinant VP2-based African horsesickness subunit vaccine candidate is determined by adjuvant. Vaccine, 20:1079-1088.         [ Links ]

VENTER, G.J., PAWESKA, J.T., WILLIAMS, R. & NEVILL, E.M. 1999. Prevalence of antibodies against African horse sickness (AHS) and equine encephalosis (EE) virus in donkeys in southern Africa, in Equine infectious diseases VIII, edited by U. Wernery, J.F. Wade, J.A. Mumford & O.R. Kaaden. Newmarket: R & W Publications (Newmarket) Ltd.         [ Links ]

VERWOERD, D.W. & HUISMANS, H. 1972. Studies on the in vitro and the in vivo transcription of the bluetongue virus genome. Onderstepoort Journal of Veterinary Research, 39: 185-191.         [ Links ]

VERWOERD, D.W., HUISMANS, H. & ERASMUS, B.J. 1979. Orbiviruses, in Comprehensive virology, edited by H. Fraenkel-Conrat & R.K. Wagner. New York: Plenum Press.         [ Links ]

 

 

Accepted for publication 21 April 2008-Editor

 

 

† Present address: 384 Amberglen, P.O. Box X004, Howick, 3290, South Africa
* Author to whom correspondence is to be directed. E-mail: alan.guthrie@up.ac.za