- Salt Lake County reports Utah's first 2025 West Nile virus human case.
- The patient, infected in July, is recovering at home after hospitalization.
- Mosquito abatement districts in Magna Salt Lake City and South Salt Lake Valley tested positive.
SALT LAKE CITY — The Salt Lake County Health Department on Thursday announced Utah's first human case of West Nile virus for 2025. The individual was hospitalized with the severe, neuroinvasive form of the mosquito-borne illness but is now out of the hospital and recovering at home.
According to public health officials, the peron was likely infected in late July near the Jordan River in the southern part of Salt Lake County. No additional details about the person are available due to health privacy laws.
The department said in a news release that three Salt Lake County mosquito abatement districts have tested positive for West Nile virus: Magna, Salt Lake City and South Salt Lake Valley. Statewide, 108 mosquito samples have tested positive.
To look for the virus, mosquitoes are trapped and then tested. Health officials call the collections "mosquito pools."
But mosquitoes can travel several miles, so everyone in the area is encouraged to take precautions.
About West Nile virus
West Nile virus is carried primarily by birds and spread by certain mosquitoes. Humans get it when a mosquito bites infected birds and then humans. But unlike birds, people do not get high enough levels of the virus in their bloodstream to infect mosquitoes who might then pass it on. So humans are called "dead-end hosts," per the Centers for Disease Control and Prevention.
The CDC notes that it's rare for a person to transmit it to someone else by way of blood transfusion, organ transplant or through pregnancy, delivery or breastfeeding. But it can happen, so those who were recently diagnosed with West Nile virus should not donate blood or bone marrow for 120 days.
Symptoms can appear within two days to two weeks and may include fever, headache, body aches, vomiting, diarrhea or rash. The most severe form is neuroinvasive West Nile virus, which can be very serious or even deadly. The symptoms of severe West Nile can include high fever, stiff neck, disorientation, coma, tremors and muscle weakness or seizures.
While 1 in 5 infected people develop symptoms, about 1 in 150 develop the serious, sometimes fatal illness.
Those most at risk of symptomatic West Nile virus are folks with compromised immune systems and adults 50 and older, per the health department.
The virus has no specific treatment; rather, care providers try to manage the symptoms.
Preventing West Nile virus
Since there's no vaccine, the best prevention is avoiding mosquito bites.
The Salt Lake County Health Department offers these tips from now until the first hard freeze:
- Use an EPA-registered mosquito repellent with DEET, picaridin, IR3535 or oil of lemon eucalyptus. Directions for application vary, so follow the advice on the package.
- If you're outside between dusk and dawn, when the type of mosquitoes that can carry the illness are active, wear long sleeves and pants
- Drain standing water in yards, including in plant trays, dog dishes, buckets and old tires.
- Keep roof gutters clear of debris.
- Clean and stock garden ponds with mosquito-eating fish or mosquito dunks. For help, contact your local mosquito abatement district.
- 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 hot days.
