First human case of West Nile Virus confirmed in San Bernardino County

San Bernardino County Public Health Department announced last week that the first human case of West Nile virus (WNV) in the county for 2026 has been confirmed. The case was identified in a resident of the city of San Bernardino. This is the first reported human case in San Bernardino County since 2024, when seven cases were reported.

“West Nile virus infection continues to be a health concern in our region, particularly during the warmer months when mosquito activity increases,” said San Bernardino County Health Officer Sharon Wang, D.O. “Residents can reduce their risk by using insect repellent, wearing protective clothing and eliminating standing water around their homes. These simple steps can help protect you, your family and your community.”

WNV spreads through the bite of an infected Culex species mosquito that has previously bitten or fed on an infected bird. Symptoms typically occur three to five days after a bite, although many people do not experience symptoms. Symptoms of WNV include fever, headache, body aches, nausea, vomiting and skin rash.

Seek medical attention immediately if you experience any of the following symptoms:

• High fever
• Severe headache
• Neck stiffness
• Sudden vision loss
• Numbness or tingling
• Confusion
• Muscle weakness
• Paralysis
• Loss of consciousness

The County is asking residents to take these steps to protect themselves and their families from mosquito bites:

• Drain: Take a few minutes to walk around your property to remove standing water where mosquitoes can lay eggs. Check birdbaths, ponds, old tires, buckets, flowerpots, clogged gutters and other areas where water collects. Maintain your pool by keeping the water clean, circulating, and properly chlorinated to prevent mosquito breeding. If you see mosquitoes breeding, then report it to Public Health – Environmental Health Services.
• Dress: Enjoy the outdoors? Wear protective clothing such as socks, shoes, light-colored, loose-fitting long pants and long-sleeved shirts when gardening, barbecuing, picnicking, camping or hiking.
• DEET: Don’t forget to use insect repellent containing DEET, picaridin, IR3535 or oil of lemon eucalyptus. Follow the product label instructions.
• Defend: Prevent mosquitoes from entering your home by ensuring doors and windows have tight-fitting screens that are free of tears and holes. If you notice an increase in mosquito activity around your neighborhood or workplace, report it to Public Health – Environmental Health Services.