Louisville's 9 cases of West Nile virus this year are the most since at least 2014

LOUISVILLE, Ky. (WDRB) -- Louisville health leaders said nine human cases of West Nile virus have been confirmed so far in 2025, seven of whom have required hospitalization.

In a news release Tuesday, the Louisville Metro Department of Health and Wellness said all those affected individuals are between the ages of 40 and 70. No deaths have been reported this year.

"We are seeing a higher-than-usual number of West Nile virus cases this season, and we urge residents to take mosquito prevention seriously," Connie Mendel, chief health strategist for LMPHW, said in a news release. "Assume mosquitoes are carrying West Nile virus no matter what ZIP code you live in. Please take precautions to avoid being bitten."

Infections of West Nile virus have fluctuated in the past several years. Here are year-by-year numbers released by the health department:

2025 (to date): 9
2024: 1
2023: 7
2022: 3
2021: 1
2020: 0
2019: 2
2018: 5
2017: 2
2016: 2
2015: 0

The health department is advising residents and visitors to the area to take precautions to prevent mosquito bites.

"West Nile virus has been present in mosquitoes for years. We work year-round to reduce the mosquito population and we continue to urge everyone to protect themselves against mosquito bites," Louisville’s Chief Health Strategist Connie Mendel said in a statement. "No matter what ZIP code you live in, please take precautions to avoid being bitten."

In most instances, people infected with West Nile either show no symptoms or relatively mild symptoms. The chance of developing a serious neurologic illness such as encephalitis or meningitis from the virus is less than one percent, but serious illness can occur in people of any age. However, people over 60 are at the greatest risk along with people diagnosed with cancer, diabetes, hypertension, kidney disease and people who have received organ transplants.

Experts said the best thing you can do is pay attention to open water on your property.

You're also encouraged to wear long clothing, such as pants and long-sleeved shirts, to minimize skin exposure and using repellent to keep mosquitoes at bay.

Health officials urge all residents, not just those where infected mosquitoes have been found, to protect themselves and their families by following these steps:

Use insect repellents when outdoors and use repellents with DEET, picaridin, IR3535 or lemon eucalyptus oil.
Weather permitting, wear long sleeves, long pants and socks outdoors as mosquitoes can bite through lightweight fabrics. Also, treat your clothes with insect repellent.
Be extra careful during early morning or at dusk when mosquitoes are more active.
Eliminate standing water from flowerpots, gutters, buckets, pool covers and pet dishes
Install or repair screens on windows and doors to keep mosquitoes out.

To report mosquitoes in your neighborhood, call 311 or 502-574-5000.

Louisville health officials say West Nile virus detected in 5 more neighborhoods

Louisville health officials encourage vigilance after mosquitoes found with West Nile virus