West Nile Virus Cases Surge Across 32 U.S. States as Summer Peaks

The U.S. Centers for Disease Control and Prevention (CDC) reports that, as of August 18, its ArboNET surveillance system recorded 222 human West Nile virus cases nationwide, including 156 neuroinvasive cases—the most severe form affecting the brain and nervous system. The season has already claimed eight deaths, with five fatalities in Arizona and three in California. The CDC notes that West Nile activity typically peaks in late summer and early fall, and the current data show the virus circulating well beyond areas where human cases have been confirmed.

Newsweek

Arizona leads the nation with 76 reported cases, followed by Texas (31) and California (29). In total, human infections have been documented in 32 states this year, while 18 states—primarily in the Midwest, Mid-Atlantic, and Northeast, plus Alaska and Hawaii—have reported none. County-level maps also reveal widespread infection of mosquitoes, birds, and other animals, indicating extensive viral activity across the country.

Newsweek

The CDC estimates that roughly 80 % of infected individuals remain asymptomatic, while about 20 % develop mild West Nile fever. Less than 1 % progress to neuroinvasive disease, which carries a ?10 % case-fatality rate. Older adults, particularly those 65 years and older, face the highest risk of severe neurologic complications. People with weakened immune systems or chronic medical conditions are also more vulnerable.

Newsweek

Because no vaccine or specific antiviral treatment exists for the general public, the CDC emphasizes personal protection. Recommended measures include using Environmental Protection Agency (EPA)-registered insect repellents, wearing long-sleeved clothing during peak mosquito activity, and ensuring window and door screens are intact. Eliminating standing water—such as in flower pots, buckets, bird baths, pet dishes, and clogged gutters—reduces mosquito breeding sites.

Newsweek

The ongoing spread underscores the importance of continued surveillance of both human cases and animal reservoirs. While most infections are mild, the potential for severe neuroinvasive disease and death remains, especially in high-risk groups. Public health officials urge communities to adopt preventive actions now to mitigate further transmission as the summer season progresses.

Newsweek