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Posted 08.18.06


MU Vet Reports Surge in West Nile Cases

Gayle Johnson says Public, Horse Owners Should Remain Cautious

COLUMBIA, Mo. -- As of Aug. 15, the number of West Nile virus cases in horses has exceeded the number recorded in Missouri for the entire season last year, according to Gayle Johnson, a University of Missouri-Columbia veterinarian. More than 50 percent of the horses tested in the last month have the disease, and scientists are reporting a high percentage of birds are testing positive for the disease.

"While the disease has been in the state for several years, everyone needs to maintain vigilance in order to prevent infection of mammalian hosts," Johnson said. "If people suspect that their horses may have contracted the disease, they should contact their local veterinarian immediately. In addition, people should try to eliminate stagnant wate, repair damaged window screens and wear mosquito repellant, especially at dawn and dusk when mosquitoes capable of spreading West Nile virus are more active."

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According to MU veterinarians, humans, birds and horses are most susceptible to the disease. While they can be infected by West Nile virus, dogs, cats and other small pets rarely become ill. The virus is spread through mosquito bites. A small percentage of mosquitoes carry the virus. According to the Centers for Disease Control, only one susceptible person in about 150 bitten by an infected mosquito will develop severe illness.

Most of the new West Nile cases in horses have occurred in the southern half of the state, but birds and mosquitoes carrying the disease have been distributed widely over the entire state. As of Aug. 16, five humans in Missouri have been hospitalized with the disease.

"We strongly encourage horse owners to consider immunizing or boosting their animals to prevent this potentially devastating disease," Johnson said. "More information on immunizations or boosters are available through any local veterinarian."

In the past, West Nile cases in horses have typically peaked in mid-September, so there is potentially time to protect susceptible animals.

Johnson is associate director of the Veterinary Medical Diagnostic Laboratory, a division of the MU College of Veterinary Medicine. The laboratory conducts tests determining the causes of suspicious animal deaths and illnesses, and pursues research into the poisons, pathogens and viruses that cause animal and human disease. The laboratory conducts 200,000 diagnostic tests annually.



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