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Wisconsin: Crawford County horse tests positive for West Nile Virus

Christian Fernsby |
The Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) confirms that an unvaccinated 9 year old crossbred Belgian Standardbred gelding in Crawford County has died after contracting West Nile Virus (WNV).

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It is the state’s first confirmed case of WNV in a horse since 2018.

WNV symptoms in horses include fever, incoordination, hind end weakness, depression, loss of appetite, muscle tremors, teeth grinding, inability to swallow, head pressing, excessive sweating, and going down with an inability to rise.

The disease can cause brain inflammation in horses and people; it is fatal in 30% to 40% of horses showing signs of illness.

While humans can be infected by WNV, the virus does not pass directly between people and horses; the only route of transmission is from a mosquito bite.

Mosquitoes transmit the virus from birds, which serve as natural reservoirs for WNV.

Because humans and equines acquire WNV from mosquitoes, the threat of WNV normally occurs when mosquitoes are most active, from mid to late summer until the first killing frost.

DATCP encourages equine owners to talk to their veterinarians about vaccinating their horses for WNV. The American Association of Equine Practitioners (AAEP) recommends vaccinating for both WNV and Eastern Equine Encephalitis as part of the core vaccine protocol, meaning all horses should be vaccinated for these diseases. Horses that have never been vaccinated initially require two doses two to four weeks apart, followed by at least an annual booster.

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