MODESTO (CBS13) — A mosquito in Stanislaus County has tested positive for a virus, much like West Nile that could potentially cause death in humans.
The St. Louis Encephalitis virus first appeared four decades ago, and now health officials say it's been found in the Grayson area, just southwest of Modesto.
The virus has also shown up in Fresno, Kings and Kern counties in the San Joaquin Valley and north of Sacramento in Yuba County near Plumas Lake.
County health officials say this is the first time the virus has tested positive in a mosquito in Stanislaus County since 1977 and now they are working to prevent spread.
It's been 40 years since a mosquito in Stanislaus County has tested positive for the St. Louis Encephalitis Virus - which leaders with the Turlock Mosquito Abatement District say is capable of causing a potentially deadly illness.
"Mosquitos don't know boundaries so something that happens here would definitely have a regional effect in San Joaquin, in Sacramento, down south to Fresno," said David Heft, general manager of the Turlock Mosquito Abatement District.
The St. Louis Encephalitis Virus is carried by mosquitos and is similar to the West Nile Virus. It's shown up in mosquitoes – this year in a few counties in the San Joaquin Vvalley and in Yuba County.
"Historically, St. Louis was always the virus we battled previous to West Nile but as soon as West Nile got here, it disappeared and for whatever reason now has shown up again," he said.
Just like West Nile, a person who is bitten by an infected mosquito may come down with similar symptoms like headaches, confusion and seizures.
"Most people don't have any symptoms at all. You don't know you're sick. A small amount, a few people will have just fever, flu-like illness. You just kind of feel tired and have some fever, but a very small amount, one percent or less could develop infection of their brain," said Julie Vaishampayan, public health officer for Stanislaus County.
Health officials say it's important to take precautions – avoid being outside in the early evenings and mornings, cover up – wear light-colored, long-sleeved shirts – and the most important tip – reduce mosquito breeding sites around your home, which means disposing of old buckets or pots around the house
"Saucers under plant pots, you think a saucer can't hold that much water, but it's just a little bit of water that all it takes for them to lay their eggs in and to go through their life cycle," said Monica Patterson, vector biologist for Turlock Mosquito Abatement District.
No residents here have come down with the St. Louis virus. Officials are aggressively testing several sites around the county and educating people around the community.
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