Eastern equine encephalitis is a serious disease that is transmitted to humans through the bite of an infected mosquito. It is prevalent on the East Coast and around the Great Lakes and has not been detected in California. According to the U.S. Centers for Disease Control and Prevention, human eastern equine encephalitis cases occur relatively infrequently, largely because the primary transmission cycle takes place in and around swampy areas where people are less likely to go.
An average of 11 human cases of eastern equine encephalitis are reported in the U.S. each year. As of August 27, 2024, the CDC reported four human cases, in Wisconsin, New Jersey, Massachusetts, and Vermont. In addition, officials in New Hampshire have reported one death.
California mosquito control experts are continuously monitoring for disease threats and working to protect public health. West Nile virus is the most prevalent and serious disease transmitted by mosquitoes in California. An important way to protect yourself and your family from mosquito bites is to apply insect repellent containing an EPA-registered active ingredient, including DEET, picaridin, oil of lemon eucalyptus, or IR3535, to clothes and exposed skin when spending time outside.