First Avian Case of West Nile Virus in 2004 Confirmed in Oklahoma

        Oklahoma has confirmed its first positive bird for West Nile virus this year, the Oklahoma State Department of Health said today. The bird was a crow that was found dead on May 13 in McIntosh County. No human cases of the disease have yet been reported in the state.

        "This positive confirmation is significant because it is an earlier recognition of West Nile virus in Oklahoma than in the past two seasons," said Interim State Epidemiologist Dr. Kristy Bradley. "In 2002 and 2003, we did not have our first positive birds until mid-July, so essentially we are two months early, although this is consistent with national trends that indicate the disease tends to have an earlier seasonal onset in subsequent years."

West Nile virus (WNV) is a seasonal infection transmitted in Oklahoma primarily by Culex mosquitoes. These mosquitoes pick up the virus when they feed on infected birds, and then transmit the virus when they bite humans, horses and some other mammals. While the effects of the disease may be mild in most people, for some who acquire WNV, life-long disabilities may result, including recurrent headaches, difficulty concentrating, chronic fatigue, and paralysis.

        "The finding of an infected bird through our WNV surveillance program is a reminder to all Oklahomans that everyone should be practicing mosquito control prevention activities around their homes and businesses," Bradley emphasized.

        She suggested remembering the "4 D's of Defense" to protect against WNV:

… Dusk and dawn - Avoid outdoor activities during these prime times for mosquito activity.
… Dress - Wear long pants and long sleeves when outside to cover the skin.
… DEET - Use an insect repellent containing DEET (N, N-diethyl-m-toluamide) when outdoors and reapply according to directions.
… Drain - Drain those items that collect standing water around your home, yard or business. Scrub and refill pet water dishes and bird baths regularly.

Bradley said horse owners should contact their veterinarian for information on how to protect their horses from WNV through vaccination. WNV in horses in Oklahoma declined from 965 in 2002 to 169 in 2003 largely as a result of horse owners following instructions to get their horses vaccinated. A vaccination to prevent WNV in humans is not available.

For the past three years, the state health department has funded testing of dead wild birds for WNV at the Oklahoma Animal Disease Diagnostic Laboratory. Tracking clusters of birds that test positive helps direct community mosquito control interventions, such as larvicide treatment, spraying for adult mosquitoes, and mowing high grass. This year, county health departments in the following 27 counties are accepting birds for testing as part of local mosquito control efforts: Beaver, Blaine, Canadian, Carter, Cleveland, Comanche, Garfield, Jackson, Kay, Kingfisher, LeFlore, Lincoln, Logan, McCurtain, McIntosh, Muskogee, Oklahoma, Okmulgee, Ottawa, Pittsburg, Pontotoc, Sequoyah, Texas, Tulsa, Wagoner, Washington, and Woodward.

Not all dead birds are accepted for testing; blue jays, crows, cardinals, bluebirds, and birds of prey (hawks, owls, eagles, falcons) will receive priority because these types of birds are more likely to die from WNV.

West Nile virus made its official entrance into Oklahoma in 2002 when 21 human cases of the disease were confirmed with two deaths. Last year, the number of persons in Oklahoma diagnosed with WNV disease was 79, with no deaths.