Encephalitis Reported in Ventura County Woman

State health officials have turned up what is believed to be the first human case of the St. Louis encephalitis virus in Ventura County.

But officials are awaiting the results of another test before making the confirmation final.

The mosquito-borne virus causes symptoms similar to the flu, including fever and nausea. In more severe cases, it can cause brain damage or death.

Doctors strongly suspect that a 70-year-old Oxnard woman who was hospitalized in early September complaining of disorientation, severe headaches and other flu-like symptoms had the disease, said Ventura County Public Health Officer Dr. Larry Dodds.

Her illness was not reported to the public health department until mid-October, he said.

Health officials do not know how the woman may have contracted the virus, but are attempting to find her for further questioning. She was released from the hospital and later moved from the county, an official said. Neither she nor the hospital was identified.

The Ventura County case is one of two that have been reported to state health officials this year, said Robert A. Murray, deputy epidemiologist for the infectious disease branch of the state Department of Health Services.

The other case was reported in August in the El Monte area of Los Angeles County.

“For every case of this illness that is identified, hospitalized and diagnosed, there could be . . . up to 100 people who are infected,” Murray said. “The illness is more likely to be recognized the older a person is.”

The last time the state reported an epidemic of encephalitis was in 1989, when there were 29 cases. None of the victims died that year.

Before that, an epidemic hit Southern California in 1984. That year, the state recorded 26 cases, 16 in Los Angeles County. One of the victims died.

“California is an area that is endemic for mosquito-borne encephalitis,” Murray said. “It certainly is something we do have to be on guard for.”

But Bob Gallagher, who manages the county’s encephalitis virus program, said residents have little to fear because the number of mosquitoes are declining because of the onset of colder weather.

“We don’t want to cause a panic,” he said. “It becomes less and less likely that the type of mosquito that can transmit encephalitis is going to be around biting people.”