Mosquitoes collected in routine monitoring in Rolando—a neighborhood in the mid-city region of San Diego—have tested positive for West Nile virus. The find prompted County environmental health officials to remind the public to protect themselves from mosquitoes that can transmit the virus.
The positive tests mark the first time mosquitoes have tested positive in San Diego County since 2023. Four dead birds have also tested positive this year. There have been no reported human cases in San Diego County this year. However, West Nile virus remains a potentially deadly threat.
County officials said people should continue to follow the County’s “Prevent, Protect, Report” guidelines to protect themselves from mosquitoes. Those include finding and dumping out standing water around homes to keep mosquitoes from breeding.
West Nile virus is mainly a bird disease, but it can be transmitted to humans by several types of mosquitoes if they feed on an infected bird and then bite people. Some people who become infected can suffer symptoms including headache, fever, nausea, fatigue, skin rash, or swollen glands. But in rare cases, West Nile virus can make people extremely ill and even kill them.
Protecting against mosquitoes is always important in San Diego County.
County officials said people can help protect themselves from mosquito-borne illnesses by following the County’s “Prevent, Protect, Report” guidelines.
Prevent mosquito breeding
Dump out or remove any item inside or outside of homes that can hold water—whether from rain or landscape irrigation. Those things can include plant saucers, rain barrels, buckets, garbage cans, toys, old tires and wheelbarrows. Mosquito fish, available for free by contacting the Vector Control Program, may be used to control mosquito breeding in backyard water sources such as stagnant swimming pools, ponds, fountains and horse troughs.
Protect yourself from mosquito bites
Protect yourself from mosquito-borne illnesses by wearing long sleeves and pants or use insect repellent when outdoors. Use insect repellent that contains DEET, picaridin, oil of lemon eucalyptus, para-menthane-diol, 2-undecanone or IR3535. Make sure screens on windows and doors are in good condition and secured to keep insects out.
Report possible mosquito activity and dead birds
Report increased mosquito activity, unmaintained green swimming pools, and other mosquito-breeding sources, as well as dead birds—crows, ravens, jays, hawks and owls—to the County Vector Control Program by calling (858) 694-2888 or emailing vector@sdcounty.ca.gov.
For more information about West Nile Virus, go to the County Health and Human Services Agency’s West Nile virus webpage.