West Nile virus cases rise across U.S., with deaths reported in Arizona and California
The CDC has recorded more than 180 West Nile virus infections this year, including eight fatalities in 30 states, as drought conditions may be aiding mosquito transmission.
The United States has seen a surge in West Nile virus infections this year, with the Centers for Disease Control and Prevention reporting over 180 cases and at least eight deaths across 30 states. Arizona leads with 73 confirmed cases and five deaths, while California has reported three fatalities among 30 patients.
Idaho documented its first severe case in a 65-year-old resident, prompting state epidemiologist Dr. Christine Hahn to urge protective measures against mosquito bites.
"The report of the first severe West Nile virus disease of the season in an Idaho resident is a good reminder for all of us to take protective measures against mosquito bites," Dr. Hahn said.
Health officials note that while most infections are mild, the virus can cause serious neurological symptoms, including high fever, coma, tremors, vision loss, paralysis and inflammation of the brain and spinal cord. No specific treatment exists; care focuses on supportive measures such as rest and fluids.
Experts attribute the heightened spread partly to drought conditions in the western United States, which concentrate mosquitoes and birds around limited water sources, increasing transmission risk. University of Minnesota virology professor Matthew Aliota explained the mechanism.
"Drought conditions can paradoxically increase West Nile virus transmission because it concentrates mosquitoes and birds around shrinking water sources, increasing transmission risk," Aliota said.
Despite higher case numbers in some regions, mosquito populations remain below average in states such as Colorado, North Dakota and Minnesota. Authorities continue to recommend standard personal protection, including insect repellent, protective clothing and elimination of standing water around homes.
"This includes wearing insect repellent and protective clothing in addition to reducing standing water around gardens and homes where mosquitoes can lay eggs," Dr. Hahn added.