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West Nile Virus found in City of Norco

May contain: animal, insect, invertebrate, and mosquito



Northwest Mosquito and Vector Control District

1966 Compton Avenue Corona, CA 92881 (951)340-9792


For Immediate Release:


Norco Mosquito Sample Tests Positive for West Nile Virus


Norco, CA: July 6, 2023


Northwest Mosquito and Vector Control District (NWMVCD) has collected its first West Nile virus positive mosquito sample of the year in the area between Reservoir Drive and Temescal Avenue in the City of Norco. NWMVCD has also collected 3 dead birds that were tested and confirmed West Nile virus positive within the City of Norco as well.


West Nile virus is transmitted to humans and animals through the bite of an infected mosquito. Approximately 20% of the humans infected experience mild symptoms, such as fever, headache and body aches. Less than 1% of individuals will develop serious neurological illness, based on historical data.


The elderly, children or individuals with a compromised immune system are usually at a higher risk of experiencing further manifestations of the disease. Anyone with symptoms should contact their health care provider. NWMVCD requests that residents avoid creating standing water sources on their property. If residents know of any standing water sources, such as an unmaintained swimming pool, they are encouraged to report it so proper measures can be implemented by NWMVCD. Residents are highly encouraged to take the following precautions and protective measures. 


Protect yourself from mosquito bites:

1.     Use insect repellents: Use a Centers of Disease Control approved insect repellent such as DEET, picaridin, IR3535 and oil of lemon eucalyptus. Make sure to use insect repellents according to the product label.

2.     Dawn and dusk: Dawn and dusk are peak mosquito biting times for many mosquitoes. Consider rescheduling outdoor activities to avoid that time.

3.     Clothing: Wearing long sleeves, long pants and socks when outdoors can reduce exposure to mosquito bites.


Protect your animals:

1.     In equine communities it is important to consult with your veterinarian about vaccinating your horse against West Nile virus.


Mosquito proof your home

1.     Dump and drain standing water: Mosquitoes lay their eggs in standing water; therefore, by eliminating these standing water sources you reduce your chance of being bit by a mosquito.

2.     Screens: Keep mosquitoes outside by having tight fitting screens on all your windows and doors.


As of July 6, 2023, West Nile virus has been found in in 14 counties in California, with 148 mosquito samples testing positive for the virus and 0 confirmed human cases. Please visit to report any mosquito problems, request mosquito inspection, report dead birds, report neglected swimming pools and submit service requests. For the latest on statewide information on mosquito-borne diseases, please visit



Eric Ballejos

Public Information and Technology Officer




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