BOX ELDER COUNTY, Utah — Health officials have confirmed the first human case of West Nile virus in the Bear River Health District for 2026. The infected individual resides in Box Elder County.
The Bear River Health Department declined to release additional information regarding the patient to protect their privacy.
The virus is spread to people and animals through the bite of an infected mosquito, which contracts the illness after feeding on birds carrying the virus. While many infected individuals do not develop symptoms, others may experience a mild illness characterized by fever, headache, body aches, or fatigue. In rare cases, the virus can cause serious neurological illness.
Mosquito abatement teams throughout Box Elder, Cache, and Rich counties recently began testing mosquito traps for virus activity, with positive samples expected in the coming days and weeks. Because mosquitoes can travel several miles, health officials urge all district residents to take immediate steps to reduce their risk of bites.
“Last winter’s temperatures were much warmer than normal, allowing the Culex species of mosquito (the primary carrier of WNV) to survive the winter in adult form with very little mortality,” said Tyson Packer, director of the Box Elder Mosquito Abatement District. “Because of such a healthy head start, combined with favorable environmental conditions, mosquito populations have been able to thrive.”
Packer noted that abatement efforts have been aggressive and will continue through the summer to reduce mosquito populations and lower the overall risk.
Officials advise residents to protect themselves by following the “five Ds”:
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Drain: Remove standing water from around homes or workplaces where mosquitoes can breed.
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Dawn and Dusk: Limit outdoor activities when mosquitoes are most active.
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DEET: Apply an EPA-approved insect repellent containing DEET or another recommended active ingredient.
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Dress: Wear lightweight, loose-fitting long sleeves and long pants when spending time outdoors.
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Door: Keep doors and windows screened, and repair any holes to prevent mosquitoes from entering the home.
Anyone who develops symptoms such as a high fever, severe headache, neck stiffness, confusion, disorientation, or muscle weakness after a mosquito bite should seek prompt medical attention.