Fourth Case of Human West Nile Virus Has County Health Officials Urging Caution
Reading Time:2minutesA fourth county resident has tested positive for West Nile virus, prompting County public health officials to urge steps to prevent mosquito bites and drain standing water. Four San. . .
Reading Time:2minutesA fourth county resident has tested positive for West Nile virus, prompting County public health officials to urge steps to prevent mosquito bites and drain standing water. Four San Diegans have contracted the virus since June, with symptom onset or positive tests occurring between June 5 to July 14, 2026. No local deaths have been reported this year. One of the recent cases required several days of hospitalization, another had mild symptoms that did not require hospitalization, and two were detected through blood-donation screening. One of the cases was acquired locally. West Nile virus mainly affects birds, but mosquitoes can spread it to people after biting an infected bird. Increases in infected mosquitoes and birds often lead to more human cases. In 2025 there were no human cases in San Diego County, but healthofficials saw an uptick in infected mosquitoes and dead birds. Last year, 34 dead birds and 182 mosquito batches tested positive for West Nile virus. So far in 2026, the virus has been detected in 23 dead birds and 10 mosquito batches. Similar increases are being seen across California and neighboring states. Most people who get West Nile virus experience no symptoms or mild illness such as headache, fever, nausea, fatigue, skin rash or swollen glands. In rare cases, it can cause severe illness or death. In October 2024, an elderly County resident with a compromised immune system died of West Nile Virus encephalitis. Mosquitoes can live near people — in backyards and even indoors. Some types of mosquitoes can also spread other diseases like chikungunya, dengue, and Zika, but only if they bite someone who is already infected. County RecommendationsPrevent mosquito breedingDump or drain anything that holds water, like plant saucers, clogged gutters, buckets, toys, old tires, and wheelbarrows. Cover rain barrel openings or use mosquito dunks. Request free mosquito-eating fishfor ponds, fountains or unused swimming pools. Protect yourself from bitesWear long sleeves and pants outdoors. Use repellents with DEET, picaridin, oil of lemon eucalyptus or IR3535. Make sure window and door screens are in good shape. Repair as soon as possible when they are not. Report mosquito problems and dead birdsReport increased mosquito activity, green or unmaintained swimming pools or dead birds (crows, ravens, jays, hawks, owls) to County Vector Control. Call (858) 694-2888 or email vector@sdcounty. ca. gov. To learn more, visit the County’s “Fight the Bite” website. Cassie N. Saunders is a communications specialist with the County of San Diego Communications Office. ContactPost navigation