California Horse Tests Positive for West Nile Virus

Officials have reported Madera County’s first and the state’s fifth confirmed equine WNV case for 2019.

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Madera County, California
Officials have reported Madera County’s first and the state’s fifth confirmed equine WNV case for 2019. | Photo: Wikimedia Commons

The California Department of Food and Agriculture (CDFA) confirmed on Aug. 28 that an unvaccinated yearling Andalusian stallion presented with clinical signs of West Nile virus (WNV), including ataxia (incoordination), drooling, fever, and lethargy, on Aug. 18. The colt was tested using IgM-capture ELISA. By the confirmation date, the attending veterinarian reported the horse still displayed signs of ataxia but had received supportive care and improved.

This diagnosis marks the first confirmed case of equine West Nile virus in Madera County for 2019 and the fifth statewide, with other affected counties including Fresno, Kern, San Bernardino, and Stanislaus.

Seventy-five percent of the WNV cases confirmed in California are typically reported in August and September, with the first case being reported in late July or early August most years, said Katie Flynn, BVMS, MRCVS, equine staff veterinarian with the CDFA. In 2019 the first case was reported on Aug. 12

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Diane Rice earned her bachelor’s degree in agricultural journalism from the University of Wisconsin, then married her education with her lifelong passion for horses by working in editorial positions at Appaloosa Journal for 12 years. She has also served on the American Horse Publications’ board of directors. She now freelances in writing, editing, and proofreading. She lives in Middleton, Idaho, and spends her spare time gardening, reading, serving in her church, and spending time with her daughters, their families, and a myriad of her own and other people’s pets.

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