West Nile Virus Cases and Mosquito Threats Expand

West Nile virus cases are rising in multiple U.S. states, with Colorado confirming its first two human cases of 2025 in Adams County and experiencing a spike in infected mosquitoes, leading to targeted spraying in Fort Collins. South Dakota is projecting its highest West Nile outbreak since 2018, while Pennsylvania and Massachusetts have detected positive mosquito samples and are intensifying prevention efforts. Cumberland County, Pennsylvania, has also detected Jamestown Canyon Virus, prompting additional public health advisories. Most West Nile virus cases remain asymptomatic, but older adults and people with certain health conditions are at higher risk for severe illness. Health authorities recommend using insect repellent, wearing protective clothing, avoiding peak mosquito hours, and eliminating standing water. Many local health departments are distributing free insect repellent to help reduce the spread of mosquito-borne illnesses.