CLAIBORNE COUNTY, Tenn. (WOKI / WVLT) — Federal health officials have confirmed a rare case of La Crosse virus in Claiborne County, marking Tennessee’s first reported human infection of the mosquito-borne disease in 2026.
According to newly released data from the Centers for Disease Control and Prevention, a Claiborne County resident has been diagnosed with a neuroinvasive case of La Crosse virus, a more severe form of the illness that affects the nervous system.
The Tennessee case is currently the only human infection reported in the state this year. Nationwide, the CDC has documented just four cases of La Crosse virus in 2026, with the remaining cases reported in Alabama, North Carolina, and Ohio.
La Crosse virus is spread through the bite of infected mosquitoes, primarily the eastern tree hole mosquito. The virus is closely associated with the Appalachian region, where wooded environments and favorable mosquito habitats contribute to its continued presence.
While many people infected with La Crosse virus experience no symptoms or only mild flu-like illness, neuroinvasive infections can be much more serious. In severe cases, the virus can cause encephalitis, an inflammation of the brain, or meningitis, an inflammation of the membranes surrounding the brain and spinal cord. These cases often require hospitalization and close medical monitoring.
Health experts note that the mosquitoes responsible for transmitting the virus commonly breed in standing water found in tree holes, discarded tires, clogged gutters, flower pots, and other containers that collect rainwater.
In response to the confirmed case, health officials are encouraging residents across Claiborne County and East Tennessee to take preventive measures during the remainder of the summer and early fall mosquito season.
Recommended precautions include:
- Draining standing water from yards and around homes.
- Using EPA-approved insect repellents containing DEET, picaridin, or oil of lemon eucalyptus.
- Repairing damaged window and door screens.
- Wearing long sleeves and long pants when outdoors, especially in wooded areas and during peak mosquito activity.
Public health officials say they will continue monitoring mosquito populations and tracking any additional human or animal cases throughout the region. The Claiborne County infection is the first confirmed human case of La Crosse virus reported in East Tennessee during the 2026 season.
Health departments will continue reporting new findings and disease activity to the CDC as surveillance efforts continue.
