West Nile virus has made its first known appearance in Sonoma County this year, turning up in a mosquito sample taken outside Sonoma, the Marin/Sonoma Mosquito and Vector Control District reported Thursday.
It's the earliest known occurrence of the disease in the county's mosquito population since 2008, and may foreshadow a higher incidence than usual this year, the district said.
"Our season began much earlier this year, both in terms of mosquito abundance and virus detection," the district's public relations director, Nizza Sequeira, said in a news release. "While we cannot predict the amount of West Nile virus activity that may occur in a given year, we do see the potential for a higher level of virus activity than in past years."
The infected mosquito was retrieved from the rural area of Ramal and Poehlman roads, south of Highway 12 between the cities of Sonoma and Napa, the district said.
West Nile virus has now turned up in eight California counties. Sonoma and Fresno counties are the latest to join Lake, Contra Costa, Santa Clara, San Joaquin, Los Angeles and San Bernardino counties, where the virus turned up earlier, according to the California Department of Public Health.
Three dead birds found in Lake County tested positive last month, officials there said. No human cases have occurred in the state so far this year, the state health agency said.
The mosquito-borne virus originated in Africa and arrived on the East Coast of the United States in 1999, spreading west since then, according to the state health department.
Health officials recommend people protect themselves from being bitten by avoiding being outdoors at dawn or dusk and using effective repellent. There also are many ways to suppress mosquito populations, including eliminating sources of standing water, using mosquitofish in decorative ponds and pools, screening or using lids on rain catchment containers, and properly covering septic tanks.
Only about 20 percent of the people who become infected with West Nile virus develop symptoms, which include fever, headache, body ache, nausea, rashes, swollen lymph nodes and vomiting.
About one in 150 people infected with the virus develops serious illness, which may result in neurological damage or even death. The virus was detected in 44 of California's 58 counties last year. Statewide, 379 human cases were reported, including 15 that resulted in fatalities.
Those with local mosquito problems may seek free help from the Marin/Sonoma Mosquito and Vector Control District by calling 1-800-231-3236 or visiting www.msmosquito.com.
Dead birds should be reported to 1-877-968-2473, or online at www.westnile.ca.gov to help officials monitor its spread.
You can reach Staff Writer
Mary Callahan at 521-5249 or mary.callahan@
pressdemocrat.com.
UPDATED: Please read and follow our commenting policy: