West Nile Mosquitoes Found in Louisville

August 12, 2020

West Nile Mosquitoes Found in Louisville

Fogging operations to be conducted in specific neighborhoods


The Department of Public Health and Wellness has found mosquitoes infected with West Nile virus in surveillance traps in two Louisville ZIP Code areas, 40202 and 40204. 

“West Nile infected mosquitoes are not unusual for this time of year,” said Dr. Sarah Moyer, Chief Health Strategist and director of the Louisville Metro Department of Public Health and Wellness. “Being outdoors is great for our wellbeing, and with COVID-19 widespread in our community it’s less risky than being indoors.  Enjoy the outdoors but take the appropriate precautions no matter what ZIP Code you live in. You should wear insect repellent if you go outside and remove standing water around your home.”   

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 of early morning and dusk. 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.
  • 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 drain birdbaths on a regular basis.

No human cases of West Nile have been reported in Louisville so far this year.  Here is data from previous years:

2019 - 8 human cases, 1 death
2018 - 4 human cases, no deaths
2017 - 1 non-fatal human case
2016 - 2 human cases, 1 death
2015 - 3 human cases, no deaths 

In most instances, people infected with West Nile virus either show no symptoms or relatively mild symptoms.  However, less than one percent of infected people develop a serious neurologic illness such as encephalitis or meningitis.  Serious illness can occur in people of any age. However, people over 60 years of age are at the greatest risk for severe disease. People with certain medical conditions, such as cancer, diabetes, hypertension, kidney disease, and people who have received organ transplants, are also at greater risk for serious illness.

The Louisville Metro Department of Public Health and Wellness has operated a mosquito control program for more than 60 years. The department does surveillance of mosquito populations with traps strategically located throughout the community, and tests mosquitoes for such diseases as West Nile, La Crosse, Eastern Equine and St. Louis Encephalitis. 

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 performs mosquito fogging in response to West Nile virus and other mosquito-borne diseases.

Mosquito fogging will take place on Wednesday, August 12, in the neighborhoods of Phoenix Hill, Nulu, Butchertown and Irish Hill weather permitting. Fogging occurs in the early morning or early evening hours. The Department of Public Health and Wellness uses Zenivex, a synergized synthetic pyrethroid, using an ultra-low volume fogging machine. This product offers a very low toxicity and odor. The U.S. Environmental Protection Agency and Kentucky Department of Agriculture recognize pyrethroids as safe to use without posing unreasonable risks to human health. Zenivex breaks down quickly in sunlight and does not have a residual effect.

To check if your area has been fogged or will be fogged call the mosquito hotline, 574-6641, or visit the department’s website.  To make a request regarding mosquitoes in your neighborhood call Metro Call at 311 or 574-5000.