Tests Ongoing for Cause of South African Horse Deaths

Further tests have been requested to determine the cause of death of 13 horses in South Africa's Western Cape. Veterinarians and officials with the Western Cape Department of Agriculture met Wednesday, April 18, to discuss the outbreak and resulting precautions. Some movement restrictions will remain in place.

Although original tests on the dead horses showed the presence of genetic material from African horse sickness virus (AHSV), the clinical signs, epidemiology, and post mortem findings were not consistent with AHS, leading researchers to consider another virus could be responsible.

Additional tests showed equine encephalosis virus (EEV) in some of the dead and surviving affected horses. Western Cape veterinarians reported hundreds of fever reactions and mild disease in horses.

"Although generally not regarded as a serious disease, this particular strain of EEV (Serotype-1 Bryanston) isolated in the Western Cape seems to be more pathogenic in certain individual susceptible animals, as evidenced by the recorded mortalities," a press statement released by the Department stated.

"Further laboratory results are awaited to establish whether the African horse sickness positive tests resulted from vaccine virus or from infection. A mixed infection of EEV and AHS is not ruled out at this stage."

Because of these findings, the Department of Agriculture of the Western Cape and the National Department of Agriculture have decided to maintain the ban equine movement into, through, or within the AHS Surveillance Zone and AHS Free Area. Some exceptions to this ban will be considered if strict disease prevention precautions (as issued by the State Veterinarian) are followed.

For more information see www.TheHorse.com/ViewArticle.aspx?ID=9348.

About the Author

Erin Ryder

Erin Ryder is a former news editor of The Horse: Your Guide To Equine Health Care.

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