Thursday March 30, 2023
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Louisville Mosquitoes Test Positive for West Nile

Mosquitoes found in a south Louisville location have tested positive for West Nile virus.

Mosquito BiteMosquito samples were collected in a trap as part of surveillance by the Department of Public Health and Wellness and tested by its laboratory.  The mosquitoes testing positive for West Nile were collected in the 40214 ZIP code.

There have been no human cases of West Nile virus this year in Louisville.  In 2015 there were three human cases.

But, “This is an indication that the West Nile virus is present again this year in Louisville,” said Dr. Joann Schulte, director of the Louisville Metro Department of Public Health and Wellness. “West Nile virus is most commonly transmitted to humans by mosquitoes. You can reduce your risk of being infected with West Nile virus by using insect repellent and wearing protective clothing to prevent mosquito bites.”

Fewer than 1 in 150 people infected with West Nile virus will develop serious disease.  About 1 in 5 people who are infected will develop a fever with other symptoms such as headache, body aches, joint pains, vomiting, diarrhea, or rash. Most people with this type of West Nile virus disease recover completely, but fatigue and weakness can last for weeks or months.  Less than 1 percent of people who are infected will develop a serious neurologic illness such as encephalitis or meningitis (inflammation of the brain or surrounding tissues).The elderly and those with compromised immune systems are at increased risk for serious disease from West Nile virus.

The Department of Public Health and Wellness advises people to take the following precautions:  

Avoid Mosquito Bites

  • Use insect repellents when you go outdoors. Repellents containing DEET, picaridin, IR3535, and some oil of lemon eucalyptus and para-menthane-diol products provide longer-lasting protection. To optimize safety and effectiveness, repellents should be used according to the label instructions. More information about insect repellents can be found here(
  • When weather permits, wear long sleeves, long pants and socks when outdoors. Mosquitoes may bite through thin clothing, so spraying clothes with repellent containing permethrin or another EPA-registered repellent will give extra protection. Don’t apply repellents containing permethrin directly to skin. Do not spray repellent on the skin under your clothing.
  • Take extra care during peak mosquito biting hours. Take extra care to use repellent and protective clothing from dusk to dawn or consider avoiding outdoor activities during these times.

Mosquito-Proof Your Home

  • Install or repair screens on windows and doors to keep mosquitoes outside. Use your air conditioning, if you have it.
  • Help reduce the number of mosquitoes around your home by emptying standing water from flowerpots, gutters, buckets, pool covers, pet water dishes, discarded tires and birdbaths on a regular basis.

WestNileThe Louisville Metro Department of Public Health and Wellness has operated a mosquito control program for more than 50 years. The department does surveillance of mosquito populations with traps strategically located throughout the community, and tests mosquitos for such diseases as Zika and West Nile virus.  In the spring the department pre-treats potential mosquito breeding sites with larvicide to prevent hatch offs.  In the summer it treats catch basins and fogs to control adult mosquito populations.

To check on areas to be fogged each week or to sign up for fogging alerts, call the mosquito hotline, 574-6641, or visit

To log a complaint about mosquito problems in your neighborhood, call Metro Call by dialing 311 or 574-5000. 

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