Salt Lake County has logged its first human West Nile virus case of 2026, and the infected adult is expected to recover fully. The case arrives as mosquito surveillance shows the virus circulating widely across Utah, including dozens of positive pools in the county.
The adult was not identified, according to KUTV. Bear River Health Department reported Utah's first case in late June, making the Salt Lake County case the second human infection publicly reported in the state this season.
Positive Mosquito Pools Are Climbing Across Utah
Utah Department of Health and Human Services surveillance data through July 25 counted 296 West Nile-positive mosquito pools statewide, including 86 in Salt Lake County. The same report listed 31 positive pools at the comparable point in 2025 and 18 in 2024, a sharp increase in early-season virus activity.
The warning follows a difficult 2025 season for Utah. The state's annual mosquito-borne disease report recorded 49 human West Nile cases last year, including 39 neuroinvasive cases and four deaths, according to the Utah Department of Health and Human Services.
Most Infections Are Mild Or Go Unnoticed
West Nile virus is most commonly spread by infected Culex mosquitoes. The latest state surveillance report says 70% to 80% of infected people develop no symptoms, while fewer than 1% develop serious neurological illness such as encephalitis or meningitis.
When symptoms do appear, they can include fever, headache, body aches, vomiting, diarrhea or a rash, and they typically begin two to 14 days after a bite. Severe illness can involve high fever, neck stiffness, confusion, coma, tremors, muscle weakness or convulsions.
Health officials are urging residents to use EPA-registered repellents containing ingredients such as DEET, picaridin, IR3535 or oil of lemon eucalyptus, as reported by KUTV. They also recommend wearing long sleeves and pants after dusk, emptying standing water from items such as buckets and plant trays, keeping gutters clear, and checking window and door screens.
The latest case is less severe than the one Salt Lake County reported last summer: Hoodline previously reported that the 2025 patient was hospitalized with neuroinvasive West Nile disease before recovering at home. Mosquito season is expected to continue until the first hard freeze, so the county's advice comes with plenty of summer still on the calendar.
