Santa Clara County to spray pesticide following discovery of more West Nile-positive mosquitos

Portions of San Jose and unincorporated Santa Clara County will be sprayed with an adult-mosquito-control treatment Thursday, after officials confirmed the presence of West Nile-positive mosquitos.

The presence of West Nile-positive mosquitos was confirmed in zip codes 95111, 95112, 95125 and 95136 by the County of Santa Clara Vector Control District, according to a release from the county. The county also released an interactive map where residents can view affected areas.

The spraying will center around Monterey Road and Umbarger Road. The treatment will begin around 10 p.m., weather permitting, and last between two and four hours, the county said. The treatment will be administered by truck-mounted equipment.

This spray follows the news that a Santa Clara County resident died from West Nile Virus in August — the county’s first death from West Nile this year, which was announced Aug. 14. A second resident was hospitalized with the virus, officials said. Officials could not confirm whether the virus was contracted locally in both cases.

A resident of Contra Costa County died of West Nile Virus in July, the county’s first fatal case since 2006.

The treatment follows several others since West Nile-positive mosquitos were first detected in San Jose. In July, the county conducted three spraying treatments across the city. The first spraying covered the zip codes 95127 and 95140 and centered around Calco Creek Drive. The second spraying was in zip codes 95111, 95112, 95121 and 95122 centered around Senter Road and Southside Drive, and the third spraying was in zip codes 95116, 95127, 95131, 95132 and 95133 centered around Penitencia Creek Road and North Capitol Avenue.

The district generally controls the population levels of mosquitos through integrated pest-management strategies that target immature stages of mosquitos in standing water, preventing them from reaching the adult biting stage, officials said. When West Nile Virus is detected, the county also targets adult populations to mitigate the spread of the disease.

The county added that residents do not need to relocate during the mosquito treatment, as it poses a “minimal risk” to people, animals and the environment when conducted by professionals. The pesticide breaks down quickly when exposed to sunlight.

Those who want to take extra precautions should keep people and animals inside and close doors and windows, officials said.

West Nile Virus does not cause symptoms in most people, but it can cause fever, headaches and body aches, according to the press release. In severe cases, it can cause neurological damage or death. The elderly and people with chronic medical conditions are at higher risk for complications.