Mosquitoes in San Diego's Rolando Neighborhood Test Positive for West Nile Virus

Mosquitoes collected during routine surveillance in San Diego's Rolando neighborhood have tested positive for West Nile virus, marking the first such detection in the county since 2023. ([countynewscenter.com](https://www.countynewscenter.com/mosquitoes-test-positive-for-west-nile-virus/?utm_source=openai))

This discovery has prompted county environmental health officials to remind residents of the importance of protecting themselves against mosquito bites, which can transmit the virus. Although no human cases have been reported in San Diego County this year, the presence of infected mosquitoes underscores the ongoing risk. ([countynewscenter.com](https://www.countynewscenter.com/mosquitoes-test-positive-for-west-nile-virus/?utm_source=openai))

West Nile virus primarily affects birds but can be transmitted to humans through mosquito bites. Infected individuals may experience symptoms such as headaches, fever, nausea, fatigue, skin rash, or swollen glands. In rare instances, the virus can lead to severe illness or death. ([countynewscenter.com](https://www.countynewscenter.com/mosquitoes-test-positive-for-west-nile-virus/?utm_source=openai))

To mitigate the risk, county officials are emphasizing the "Prevent, Protect, Report" guidelines:

Prevent Mosquito Breeding

Eliminate standing water around your home, as mosquitoes breed in stagnant water. Common sources include plant saucers, rain barrels, buckets, garbage cans, toys, old tires, and wheelbarrows. For larger water bodies like unmaintained swimming pools, ponds, fountains, and horse troughs, consider introducing mosquito fish, available for free through the county's Vector Control Program. ([sandiegocounty.gov](https://www.sandiegocounty.gov/deh/pests/wnv.html?utm_source=openai))

Protect Yourself from Mosquito Bites

When outdoors, wear long sleeves and pants, and apply insect repellent containing DEET, picaridin, oil of lemon eucalyptus, para-menthane-diol, 2-undecanone, or IR3535. Ensure that window and door screens are intact and secure to keep mosquitoes out of your home. ([sandiegocounty.gov](https://www.sandiegocounty.gov/deh/pests/wnv.html?utm_source=openai))

Report Mosquito Activity and Dead Birds

Report increased mosquito activity, unmaintained green swimming pools, and other potential breeding sites, as well as dead birds—particularly crows, ravens, jays, hawks, and owls—to the county's Vector Control Program by calling (858) 694-2888 or emailing vector@sdcounty.ca.gov. ([sandiegocounty.gov](https://www.sandiegocounty.gov/deh/pests/wnv.html?utm_source=openai))

In addition to these measures, the county conducts aerial larvicide applications to control mosquito populations in hard-to-reach areas. These treatments, which began in April and continue monthly through October, involve dropping granular larvicide over nearly 1,400 acres of waterways. The larvicide targets mosquito larvae and is safe for humans, pets, and wildlife. ([kpbs.org](https://www.kpbs.org/news/environment/2025/04/16/county-prepares-for-annual-aerial-bombardment-campaign-on-mosquito-larvae?utm_source=openai))

Residents are encouraged to stay vigilant, especially during the warmer months when mosquito activity increases. By following the "Prevent, Protect, Report" guidelines, the community can help reduce the risk of West Nile virus transmission.

For more information on mosquito control and West Nile virus prevention, visit the county's "Fight the Bite" website. ([sandiegocounty.gov](https://www.sandiegocounty.gov/deh/pests/wnv.html?utm_source=openai))