Nashville, TN – The Tennessee Department of Health warns that record floods in some parts of the state in early May followed by hotter than average temperatures could contribute to larger mosquito populations in the state and an increase in West Nile virus cases. TDOH urges Tennesseans to follow commonsense precautions to protect themselves from mosquito bites and the diseases they may carry.
“The best way to protect yourself from illnesses such as West Nile virus is to prevent mosquito bites,” said Health Commissioner Susan R. Cooper, MSN, RN. “There are simple precautions we can all take to reduce our contact with mosquitoes and our risk of bites.”
The Department of Health tests mosquitoes submitted from across the state to detect WNV. Identification of the virus in the mosquitoes allows the department to make people aware that WNV has been found in their area so they can take steps to protect themselves and their families. So far this year, one sample of mosquitoes in Shelby County has tested positive for WNV.
Tennessee continues to be impacted by WNV with nine human cases confirmed in 2009. While human cases in Tennessee dropped last year to less than half the number confirmed in 2008, citizens must still be vigilant in protecting themselves from the virus. In 2009, the first WNV-positive mosquitoes were not detected until early June. This year’s first positive was detected in mid-May.
“We don’t want people to have a false sense of security about their risk for West Nile virus by looking just at case numbers,” said State Medical Entomologist Abelardo Moncayo, PhD. “The abundance of water we’ve experienced has created numerous breeding opportunities for mosquitoes. And while extreme heat often dries up water, it also speeds up the breeding cycle of the mosquitoes that carry WNV and can lead to an increase in the amount of virus in the mosquitoes.”
Mosquitoes become infected with WNV by feeding on infected birds and can transmit the virus to humans and other animals, such as horses, through their bites. Most human WNV infections cause no noticeable symptoms. However, about 20 percent of infections result in symptoms that may include fever, headache and body aches. Occasionally more severe symptoms occur, and in less than one percent of human cases, WNV may cause a life-threatening infection of the brain.
Certain populations are at higher risk including the elderly, persons who abuse alcohol and those with chronic health conditions such as diabetes, hypertension, renal disease and cardiovascular disease.
Repellants are effective in reducing bites from mosquitoes. There are four repellents that can be applied to the skin: DEET, Picaridin, oil of lemon eucalyptus and IR3535. All insect repellents should be applied following label instructions, especially when used on children. In addition, certain products containing permethrin are also recommended for use on clothing, shoes and camping gear, but not on skin. Permethrin is highly effective as an insecticide and a mosquito repellent.
- Mosquito populations in Tennessee are at their peak May through October. Human cases of WNV usually occur beginning in July or August. There is no WNV vaccine for humans as there is for horses; therefore, Tennesseans are urged to take preventive measures to avoid being bitten by infected mosquitoes:
- Mosquitoes likely to transmit WNV bite at dusk and dawn, so avoid being outdoors at these times. If you must go outside during these times use repellent or wear long sleeves, long pants and socks to protect yourself.
- Eliminate standing water near your home, which can serve as a breeding ground for mosquitoes. 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.
For more information on West Nile Virus, visit the TDOH website at http://health.state.tn.us/ceds/WNV/wnvhome.asp.
