State lab Confirms West Nile Virus in Tennessee

Residents Strongly Encouraged to Take Precautions to Prevent Infection

Nashville, TN – The state Public Health Laboratory has confirmed West Nile Virus (WNV) in mosquitoes in Knoxville, Nashville and Memphis, prompting health officials to issue a statewide call to use repellents and take other precautions to prevent bites from mosquitoes and other insects.

These positive tests tell us that individuals bitten by mosquitoes in Tennessee could be at risk for contracting West Nile Virus, said Abelardo C. Moncayo, PhD, director of the Vector-Borne Diseases program for TDOH. We can help control mosquito populations and lessen the risk of infection by emptying containers with standing water, keeping doors and windows screened, and wearing mosquito repellent when outside.

Tennessee is the 10th state this year showing positive tests for the virus in mosquitoes, horses or birds. One human case of WNV has been reported in Mississippi. Last year, Tennessee reported four human cases of the illness, down from an all-time high of 56 cases of WNV in 2002.

Mosquitoes most likely to transmit WNV bite at dawn and dusk. The best way to prevent WNV infection is to avoid mosquito bites.

These simple tips can help.

• If you must go outside when mosquitoes are biting, use insect repellent or wear long sleeves, long pants and socks.
• If possible, eliminate standing water near your home. Many containers, even those as small as a bottle cap, can hold enough water for mosquitoes to breed.
• Keep windows and doors closed or cover them with screens to prevent mosquitoes from entering your home.
• Use insect repellent containing either DEET, Picaridin, oil of lemon eucalyptus or IR3535.

There are guidelines for using the suggested insect repellents. Neither DEET nor Picaridin should be used on infants younger than 2 months of age. Oil of lemon eucalyptus should not be used on children younger than the age of 3. DEET at 30 percent concentration is the maximum level recommended for children and infants over 2 months old. None of these products should be applied around the mouth or eyes at any age.

Mosquito populations in Tennessee are at their peak during May through October. We are calling on everyone to prevent mosquito bites and control the insects around homes, said John Dunn, DVM, PhD, deputy state epidemiologist and public health veterinarian with TDOH.

Mosquitoes become infected with WNV by feeding on infected birds and can then transmit the virus through their bites. Symptoms in humans may include fever and head and body aches, and usually last only a few days. The virus cannot be spread from one person to another.

WNV can cause severe illness in fewer than 1 percent of human cases. This severe illness could include meningitis or encephalitis and result in high fever, neck stiffness, stupor or disorientation. Severe cases may also cause muscle weakness or paralysis.

For more information about West Nile Virus, visit the TDOH website at http://health.state.tn.us/ceds/WNV/wnvhome.asp. To see maps of cases of WNV in United States, visit the U.S. Geological Survey website at http://diseasemaps.usgs.gov/index.html.