West Nile virus expected to reach state West Nile virus may reach South Dakota this summer, and in preparation, the state is testing birds and mosquitoes for its presence.
West Nile virus (WNV) was first detected in the United States in New York in 1999. By 2001, it had spread west and was detected in 28 states, including Iowa. The Centers for Disease Control and Prevention predicts it may reach the Rocky Mountains this summer.
WNV is primarily a bird disease, and crows are especially susceptible. Dead crows, blue jays and hawks are good indicators of WNV. Mosquitoes become infected by feeding on an infected bird and pass the virus to humans, horses, or other hosts when they bite.
Dr. Lon Kightlinger, state epidemiologist, said most people who become infected with the virus do not become ill. Some develop mild flu-like symptoms such as fever, headache, body aches, and occasionally swollen lymph glands or a rash. In rare cases, WNV may cause encephalitis, or inflammation of the brain. Individuals with severe or unusual headaches should seek medical care as soon as possible.
Kightlinger said SDSU's biology department is trapping mosquitoes from six sites in the state, the State Public Health Laboratory is testing dead birds and mosquitoes for the virus, and the Animal Disease Research and Diagnostic Laboratory will be testing horses.
Since July 2001, 1,959 mosquitoes and three birds in South Dakota have been tested for WNV and all are negative. In addition, veterinarians are watching horses for the virus and physicians are on the alert for its presence in humans.
Kightlinger offered the following suggestions to reduce the risk of being bitten by mosquitoes and to prevent transmission of WNV:
* Control and stop the breeding of mosquitoes on your property.
* Get rid of old tires and containers where water can accumulate and serve as a breeding ground for mosquitoes.
* Avoid areas where mosquitoes are present.
* Wear long sleeve shirts and long pants when in mosquito infested areas.
* Use mosquito repellents containing DEET, making sure to follow the directions on the container.
* Use bug lights and screen your doors and windows.
* A conditional horse vaccine is available. See your veterinarian.
* No human vaccine is available.
Questions about mosquitoes and dead birds can be directed to local SDSU Cooperative Extension offices. For more information, see the Department of Environment and Natural Resources "Spruce Up South Dakota" Web site at http://www.state.sd.us/denr/DFTA/WWFunding/tired.htm. Individuals with questions about WNV can visit the Department of Health's West Nile Web site at www.state.sd/doh/WestNile/ or call 1-800-592-1861. The Web site provides information about mosquito control, surveillance efforts, and submission of dead birds for testing, along with lists of other information sources.
West Nile surveillance and education in South Dakota is funded by a CDC grant to the Department of Health's Public Health Laboratory.