West Nile virus cases peak; experts urge repellents and water removal

In the United States, the number of confirmed West Nile virus cases is expected to hit its annual high in late August, the CDC said Friday. The spike follows a warm, wet summer that has created ideal breeding grounds for the Culex mosquitoes that carry the virus. Residents in the Midwest, Southeast and parts of the West should prepare for a surge in bites as the season peaks.

West Nile virus first appeared in the U.S. in 1999 and has since become the leading cause of mosquito‑borne disease deaths. Climate change, rising temperatures and increased rainfall have expanded the range of Culex mosquitoes, pushing the virus into new areas. The current season follows a record number of cases last year, when more than 2,300 people were diagnosed.

Symptoms range from mild flu‑like illness to severe neurological disease. In 2023, 1,100 people were infected, with 27 deaths, according to CDC data. Experts warn that older adults, people with weakened immune systems and those with chronic conditions are at higher risk. The CDC advises using EPA‑registered repellents, wearing long sleeves, and eliminating standing water near homes.

State health departments are ramping up mosquito control programs, including larvicide treatments and aerial spraying. The CDC is monitoring viral activity through sentinel bird surveillance and mosquito traps. Residents can report standing water or mosquito activity online. Staying informed and following preventive measures can reduce the risk of infection as the peak arrives.