Getting a handle on West Nile virus

"We expect to see steady to declining numbers of clinical West Nile virus cases this summer," states Gayle Johnson, associate professor of veterinary pathobiology at the College of Veterinary Medicine, University of Missouri, Columbia. "Reported cases in horses have significantly decreased. The horses have developed a strong immunity to the disease that can be attributed to vaccination or subclinical infection. The human population can still be exposed to the virus, however, because infected birds, especially crows and blue jays, can still be found in the environment."

West Nile virus first was detected in the Western Hemisphere in New York in 1999. According to the Centers for Disease Control, Atlanta, Ga., four out of five people infected by West Nile will not develop any symptoms, which may include fever, headache, body aches, and disorientation. The elderly are the most likely to be affected. People and animals who live in areas with a large mosquito and bird population also have a higher risk of contracting the disease.

"There are a number of steps people can take to protect themselves and their animals, including wearing long-sleeve shirts, long pants, and insect repellent when going outside at dusk or dawn," Johnson advises. "Put insect repellent on pets and horses, and try to keep them inside during peak hours of mosquito feeding. Contact a veterinarian to learn about the vaccines for horses and mosquito control for dogs. Don't forget to read insect repellent labels. Products that are safe for dogs may be toxic for cats. If people suspect they or their animals have contracted the virus, they should contact a physician or veterinarian or their county health department."

Less than 50% of people usually wear insect repellent. Moreover, there have been more than 16,000 cases of human West Nile virus since it first was detected in the U.S., reports the CDC. Johnson recommends that individuals be alert for dead birds, especially crows and blue jays, as previous research indicates they are a good predictor for the occurrence of human cases.

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