SALT LAKE COUNTY—Today the Salt Lake County Health Department (SLCoHD) confirmed this year’s first case of West Nile virus (WNV) in a county resident, an adult who is expected to recover fully. This infection is the second confirmed human case of WNV in Utah so far this season. In late June, the Bear River Health Department reported the state’s first human case of the season.
So far in 2026, the three mosquito abatement districts in Salt Lake County have detected WNV in 86 different mosquito samples throughout the county. Statewide, 296 mosquito samples have tested positive. Last year at this time, 39 samples had tested positive statewide; 18 samples in the state had tested positive at this time in 2024.
Because mosquitoes can travel several miles, everyone in the county—regardless of exact location—should take precautions against mosquito bites to avoid exposure to the virus.
Although only some mosquitoes carry WNV, there is no way for residents to tell which mosquitoes may be infected so it is important to minimize all exposure opportunities during mosquito season (which will continue until the first hard freeze):
- Use an EPA-registered mosquito repellent with DEET, picaridin, IR3535 or oil of lemon eucalyptus; follow package directions about application.
- After dusk, wear long sleeves and pants.
- Drain standing water in yards (old tires, potted plant trays, pet dishes, toys, buckets, etc.).
- Keep roof gutters clear of debris.
- Clean and stock garden ponds with mosquito-eating fish or mosquito dunks; contact your local mosquito abatement district for assistance with prevention in ponds.
- Ensure door and window screens are in good condition so mosquitoes cannot get inside.
- Keep weeds and tall grass cut short; adult mosquitoes look for these shady places to rest during the hot daylight hours.
WNV can cause mild to severe illness and many people may not even know they have been infected. Symptoms of WNV infection appear within 2 to 14 days of a mosquito bite and include fever, headache and body aches. More severe infections may include high fever, neck stiffness, disorientation, coma, tremors and muscle weakness or convulsions. It is estimated that less than 1% of people infected with WNV will develop the neuroinvasive form of the disease, which can result in debilitating long-term complications or death.
People over age 50 and people with weakened immune systems are at the highest risk of illness due to WNV, but anyone can become ill from the bite of an infected mosquito. WNV is not transmissible from person to person.
There is no specific treatment for WNV infection other than to treat symptoms. If you think you have WNV infection, contact your health care provider.
WNV was first detected in the U.S. in 1999 and in Utah in 2003. Last year, 49 people in Utah are known to have contracted the virus; 39 of those resulted in the neuroinvasive form of the disease and 4 passed away. Because only 20–30% of infected people will have any symptoms at all—and many of those will notice only minor, flu-like symptoms—it’s likely that infection with WNV is more prevalent than the reported case numbers indicate.