Encephalitis Virus Found in Wild Birds

Times Staff Writer

Wild birds carrying a virus that can cause encephalitis in humans have been captured in recent weeks in widely separated neighborhoods of Orange County, according to a County Vector Control District official.

“We don’t know if this is really an unusual situation, and we don’t think there is any reason for panic,” B. Fred Beams, assistant manager for the vector district, said Thursday.

“But we do know (infected) birds are out there,” he said, “so there is a chance people can get bitten by mosquitoes that have picked up the virus from the birds.”


He said his agency has trapped, tested and released more than 12,000 wild birds this year. In that number, 10 house finches and sparrows, caught in such communities as Irvine, Huntington Beach, Fullerton and San Juan Capistrano since last month, have tested positive for the disease, which is potentially fatal to humans.

Birds pierced by virus-carrying mosquitoes then become carriers, infecting other mosquitoes that pierce the birds. The virus, which affects humans, is known as St. Louis encephalitis.

Evidence that the disease-carrying mosquitoes, which need quiet water for breeding, were in Orange County first turned up in 1984 when chickens in a sentinel flock in a portion of Irvine’s San Joaquin Marsh tested positive. Beams said five people in Orange County were infected that year but all survived. One person died in Long Beach. Beams said he knew of no illnesses in Orange County since 1984.

Symptoms of St. Louis encephalitis include headaches, a rising temperature and aching muscles, all similar to influenza symptoms. There is no treatment except “just waiting it out,” and the result can be permanent brain damage or death.

Beams said healthy people between the ages of 20 and 50 can assume they have only a touch of flu, but younger and older persons can feel the affects more strongly and should be especially careful to keep themselves protected from mosquito bites by proper clothing or repellents.

In the meantime, he said, despite the relatively dry season, “we’re still finding a lot of back-yard breeding spots for mosquitoes” such as neglected swimming pools, old pots, wheelbarrows and the like in which water has collected.


While the Vector Control District works at controlling insects in ditches, gutters, flood control channels and other public sites, Beams said “it would be a big help” if homeowners cleaned up their own breeding places by getting rid of standing water in various containers.

“We’ll even supply them with mosquito larvae-eating fish for their unused swimming pools, fish ponds and such,” he said.