Five cases classified as neuroinvasive with severe symptoms that could include brain inflammation

Kansas health officials are sounding the alarm as West Nile virus cases surge across the state during the peak of mosquito season.

As of August 15, 2025, the Kansas Department of Health and Environment (KDHE) reports six confirmed cases this year, with five classified as neuroinvasive—a severe form of the virus that can lead to brain inflammation, paralysis, and vision loss.

These cases have been identified in both north-central and south-central regions of the state, prompting health authorities to urge heightened precautions among residents.

Jill Bronaugh, spokesperson for KDHE, explained the difference between neuroinvasive and non-neuroinvasive West Nile virus infections.

“Non-neuroinvasive cases typically involve flu-like symptoms such as fever, body aches, and fatigue, whereas neuroinvasive cases indicate that the virus has affected the central nervous system,” Bronaugh said.

She added that neuroinvasive infections often require extended hospital care and can result in long-term complications such as muscle weakness or disorientation.

“These cases are generally more severe and include symptoms such as high fever, inflammation of the brain and surrounding tissue, disorientation, paralysis or muscle weakness, numbness, and vision loss,” Bronaugh noted.

While the current case count remains below last year’s totals, KDHE and the Centers for Disease Control and Prevention (CDC) warn that risk levels are expected to rise as mosquito activity reaches its late-summer peak.

In 2024, Kansas recorded 64 West Nile virus infections, including four deaths. Nationwide, the CDC estimates that approximately 2,000 people are diagnosed annually, although mild cases often go unreported, making true infection rates potentially much higher.

KDHE maintains a live West Nile virus dashboard that updates weekly during the surveillance season, which runs from July through September. The agency emphasizes the importance of early detection and public awareness.

“With the summer heat and rainfall creating ideal mosquito breeding conditions, it is crucial for residents to take personal precautions to reduce the risk of infection,” Bronaugh said.

Recommended measures include applying EPA-registered insect repellent, wearing long-sleeved shirts and pants outdoors, and eliminating standing water around homes where mosquitoes can lay eggs.

The virus is primarily spread through bites from infected Culex mosquitoes, which become carriers after feeding on infected birds. Once bitten, symptoms generally appear within 2 to 6 days.

Early indicators of neuroinvasive infection can include stupor, tremors, convulsions, or severe headaches. Hospitalization is often required for patients experiencing central nervous system involvement.

While no specific antiviral treatment exists for West Nile virus, supportive care in a medical setting can significantly improve outcomes.

According to the CDC, most individuals infected with the virus eventually recover, and those who survive are believed to gain lifelong immunity.

Local healthcare providers are actively monitoring patients who present with symptoms consistent with West Nile virus, especially among older adults and individuals with weakened immune systems, who are at the highest risk for severe illness.

Emergency rooms across Kansas have been advised to be vigilant for potential cases and to report suspected infections promptly to KDHE.

The increase in cases comes as public health officials continue efforts to control mosquito populations. State and local vector control programs are deploying larvicides and utilizing mosquito traps to monitor and reduce the presence of infected insects.

Educational campaigns have also been launched to inform residents about proper outdoor protection and habitat management.

“Mosquitoes are more than just a nuisance—they are a significant public health threat,” Bronaugh emphasized.

“Everyone should take simple steps to minimize bites and breeding sites around their homes. Wearing protective clothing, using repellents, and removing standing water are small actions that can have a major impact on preventing the spread of this virus.”

The CDC also notes that severe cases of West Nile virus, while relatively rare, can have long-lasting neurological effects. Patients who recover from neuroinvasive infections may experience lingering weakness, cognitive difficulties, or vision problems.

As such, timely medical attention is critical. Public health experts are urging those experiencing symptoms such as sudden fever, severe headache, or neurological changes to seek immediate care.

West Nile virus first appeared in the United States in 1999 and has since become endemic in most states, with seasonal spikes during the summer and early fall.

Kansas has seen periodic outbreaks over the years, with mosquito activity and environmental conditions driving the intensity of each season.

Experts warn that climate patterns, including hotter summers and increased rainfall, may contribute to higher transmission rates in the coming years.

As Kansas heads into the peak of mosquito season, officials stress the importance of personal responsibility in reducing exposure.

Community-wide cooperation, including proper maintenance of public spaces, consistent use of mosquito control measures, and vigilance in reporting suspected cases, is crucial to keeping infection rates low.

“West Nile virus is a serious illness, but it is also preventable,” Bronaugh said. “By following recommended safety practices, residents can protect themselves and their families.”

Health departments across the state are coordinating closely with hospitals, laboratories, and the CDC to track the progression of this year’s outbreak.

With mosquito season expected to continue through September, authorities continue to encourage residents to stay informed and proactive in preventing bites.

Protective measures, public awareness, and early treatment remain the cornerstones of managing the risk of West Nile virus in Kansas communities.