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Grant County horses hit with West Nile virus; horse cases reported in five counties now

OLYMPIA — West Nile virus (WNV), a potentially fatal disease in equines, has been confirmed in two horses in Grant County, the first cases in the county for 2009, the Washington State Department of Agriculture announced today.

A 14-year-old Quarter horse gelding from Ephrata has been euthanized. Also euthanized was a five-year-old Quarter horse mare from Grand Coulee. Neither horse had been vaccinated for WNV.

Two additional cases confirmed today by the Washington Animal Disease Diagnostic Laboratory in Pullman include a four-year-old Haflinger mare in Othello, which has almost recovered. The horse was not vaccinated. A four-year-old Arabian gelding in Yakima is recovering. The Yakima horse was not current with its vaccinations.

The total number of confirmed cases of WNV infection in horses stands at 17 as of Aug. 18, with cases reported in Adams, Benton, Kittitas, Yakima and now Grant counties. The first cases were announced July 24.

WNV is spread by mosquitoes that have fed on an infected bird. The disease can sicken people, horses, many types of birds, and other animals. It is not spread from horses to other animals.

Last year, Washington had confirmed cases of WNV in horses in Yakima, Grant, Benton and Kittitas counties. In previous years, WNV horse cases have been detected in Western Washington as well.

WNV is fatal in about one-third of all horses that show clinical signs, although most horses do not become ill and show no symptoms at all. Those that do become ill display loss of coordination, loss of appetite, confusion, fever, stiffness, and muscle weakness, particularly in the hindquarters.

Veterinarians who learn of potential WNV infections in horses or other animals should contact the State Veterinarian's Office at (360) 902-1881.

Additional information on WNV can be found at the state Department of Health Web site at www.doh.wa.gov/WNV and at the U.S. Department of Agriculture Web site at www.aphis.usda.gov/vs/nahss/equine/wnv.

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