The first case of West Nile virus (WNV) disease in Indiana in 2026 has been reported in an Allen County resident. No additional information about the case will be released to protect patient privacy. 

Mosquito testing by the Indiana Department of Health shows that the risk for WNV is elevated across the state. Specifically, 33 counties have had mosquitoes test positive for West Nile virus. Indiana reported 39 human cases of WNV in 2025. The increased amount of rain and standing water will impact the number of mosquitoes. 

The IDOH conducts routine surveillance for multiple mosquito-borne viruses of public health importance, including West Nile virus, Eastern equine encephalitis virus, La Crosse virus and related virus, and St. Louis encephalitis virus. The mosquito-borne surveillance program is based on national guidelines and includes mosquito surveillance, human case surveillance and equine case surveillance based on the county. 

“All Hoosiers should take precautions to prevent mosquito bites while outdoors,” said State Health Commissioner Lindsay Weaver, MD, FACEP. “The risk for mosquito-borne diseases won’t go away until the first hard freeze this fall.”

Most people infected with West Nile virus have no symptoms. Some will develop flu-like symptoms, which can include fever, headache, body aches, joint pains, vomiting, diarrhea, or a rash. A small number will develop a more severe form of the disease affecting the nervous system, including inflammation in the brain and spinal cord, muscle paralysis, or even death. 

People older than 60 years and those with weakened immune systems are at higher risk of severe West Nile virus disease.