Heat and Habitat Shifts Push California Toward Vector-Borne Disease Spike

A warming climate and disrupted ecosystems are expanding the range of disease-carrying mosquitoes and fleas in California, fueling spikes in West Nile virus and raising dengue and flea-borne typhus risks; experts say multiple factors—heat, urban expansion, wildlife interactions, and rodenticide bans—are at play, making California a focal point for the growing threat of vector-borne diseases.