California Faces Increasing Risk of Mosquito-, Tick-, and Flea-Borne Diseases

California is experiencing a growing risk from mosquito-, tick-, and flea-borne diseases, with a recent study in The Lancet Regional Health Americas indicating that 18.2 million Californians are at risk for local dengue transmission at least one month a year. Recent detections include tularemia on Long Island, a Marin County park teeming with fleas (which can carry plague and typhus), and a rare tick-borne bacterium in Sonoma County. West Nile virus activity is also at a 20-year high in California, with 373 positive dead birds reported statewide as of mid-August.