THOUSAND OAKS : Encephalitis Virus Believed Contained

A potentially deadly virus discovered among chickens near a sewer treatment plant last month is believed to be contained to the Thousand Oaks area, an environmental health official said Thursday.

No signs of the St. Louis encephalitis virus, which is carried by mosquitoes, have been found among local flocks at a Fillmore fish hatchery and at the Strathearn Historical Park in Simi Valley, said Bob Gallagher, manager of Ventura County’s encephalitis virus program.

“That’s a good sign. That means there were no new exposures,” Gallagher said.

The chicken flocks are part of an encephalitis monitoring program established seven years ago and serve as an early warning system. Officials issued a warning last month to county residents to avoid mosquito-infested areas after tests revealed the Thousand Oaks flock was infected with the virus.

However, the county has still not received the results from tests of mosquitoes captured in Thousand Oaks in early October, Gallagher said.

If those tests indicate the number of mosquitoes carrying the virus is widespread, “we would issue a more strongly worded warning to the public,” Gallagher said.

The encephalitis virus causes symptoms similar to the flu, causing a fever and nausea. In more severe cases, patients can die. No human cases have ever been reported in Ventura County.