Mosquitoes collected in the city of Colton have tested positive for West Nile virus. This is the first collection of mosquitoes that have tested positive in 2025 within the area served by the Environmental Health Services Mosquito and Vector Control Program (MVCP). MVCP is taking steps to eliminate mosquito breeding hazards.
“West Nile virus can cause a serious illness in humans; therefore, I urge residents to take precautions to protect themselves against mosquito bites,” said San Bernardino County Health Officer Sharon Wang, D.O.
People bitten by an infected mosquito may develop West Nile fever and experience flu-like symptoms, which may include fever, body aches, skin rash and fatigue. In some people, West Nile fever can develop into a more serious form of the disease such as brain damage, permanent muscle weakness and even death. If you have been bitten by a mosquito and are experiencing these symptoms, contact your medical care provider.
Residents can protect themselves from West Nile virus by following these tips:
- Drain or dump – Remove all standing water around your property where mosquitoes can lay eggs such as birdbaths, green swimming pools, ponds, old tires, buckets, flower pots, clogged gutters and puddles from leaky sprinklers.
- Dress appropriately when outdoors – Wear socks, shoes, long pants, and long-sleeved shirts that are loose fitting and light colored.
- Apply insect repellent – Check that your insect repellent contains DEET, Picaridin, IR3535, or oil of lemon eucalyptus and apply it according to the manufacturer’s directions.
- Doors – Make sure doors and windows have tight-fitting screens. Repair or replace screens that have tears or holes to prevent mosquitoes from entering your home.
Property owners with pools/spas must keep them clean to prevent mosquitoes from breeding. Mosquitoes lay their eggs in unmaintained green pools and can fly up to 20 miles, potentially transmitting the virus and impacting entire neighborhoods. As birds are susceptible to West Nile virus, any dead birds (e.g. crows, jays, magpies, ravens, sparrows, finches or raptors) found in local areas should be reported to assist in monitoring for the virus.
To learn more about West Nile virus or to report a dead bird, please visit westnile.ca.gov. For more information or to report a green pool or mosquito breeding source, contact the San Bernardino County Department of Public Health Environmental Health Services at 800-442-2283 or visit our website.