SAN DIEGO, CA — A dead American crow tested positive for West Nile virus in San Diego, prompting county environmental health officials to remind residents to protect themselves from mosquitoes that can spread the disease to people.
The infected crow, which was found in the North Park neighborhood, is the first detection of West Nile virus this year in San Diego County. No human cases have been reported so far in 2026, officials said.
West Nile virus primarily affects birds but can spread to humans when certain types of mosquitoes feed on infected birds and then bite people.
Health officials said the virus remains a potentially deadly threat. In 2015, 44 county residents tested positive for West Nile virus and six people died.
Warmer temperatures combined with winter rain could lead to an earlier start to mosquito season across the county, officials said.
County Vector Control has already detected early mosquito activity and is increasing surveillance and treatment of breeding sources.
Crews monitor around 1,600 potential mosquito breeding sites and apply larvicide by air, boat, truck and hand crews. Staff also respond to community complaints about mosquito activity and give presentations to neighborhood groups about mosquito prevention.
County officials urged residents to dump out standing water or remove items that can hold water, such as plant saucers, buckets, rain barrels, garbage cans, toys, old tires and wheelbarrows. The Vector Control Program also offers free mosquito-eating fish for backyard ponds, fountains, unused swimming pools and horse troughs.
Residents were also advised to wear long sleeves and pants, and use insect repellent while outdoors to protect themselves.
Residents can report mosquito activity or mosquito breeding sources to the County Vector Control Program at 858-694-2888 or vector@sdcounty.ca.gov.