Experts Warn 5 Mosquito-Borne Diseases Threaten U.S. as Climate Change Extends Transmission Seasons
Updated
Updated · The Washington Post · Jun 23
Experts Warn 5 Mosquito-Borne Diseases Threaten U.S. as Climate Change Extends Transmission Seasons
3 articles · Updated · The Washington Post · Jun 23
Summary
Five mosquito-borne diseases—led by West Nile virus—are the most common U.S. threats, with experts warning that warming weather and infected travelers are raising transmission risk.
About 2,000 West Nile cases are reported annually, mostly in July through September, and rare neuroinvasive infections can cause meningitis or encephalitis, especially in older or immunocompromised people.
Eastern equine encephalitis is far rarer—218 cases from 2003 to 2025—but severe cases carry a 30% fatality rate, while Jamestown Canyon and La Crosse can also trigger encephalitis.
St. Louis encephalitis remains sporadic at 1 to 49 cases a year, but warmer conditions may support year-round spread in some Southern areas and continued circulation in parts of the West.
Dengue, chikungunya, malaria and Zika are still mostly travel-linked in the U.S., though experts said locally transmitted dengue has risen in California, Florida and Texas.