West Nile threat looms

Silicon Valley's neighbors, urban San Francisco and rural San Benito County, have something in common as the West Nile virus looms: Neither has its own full-fledged agency to control mosquitoes.

Many Bay Area counties do, and they are already working against the blood-sucking bugs that spread the deadly virus.

West Nile, which first appeared in California in August, is expected to spread throughout the state this year. That means areas without their own mosquito control agencies are going to have to pay more attention to the insects, even if they don't have the same expertise or equipment as nearby counties.

San Francisco is already looking at ways to step up mosquito tracking and control efforts. Dr. Rajiv Bhatia, director of occupational and environmental health, said the department is considering everything from mosquito traps to killing off bugs if too many breed in the city's sewage treatment system.

San Benito County, with a small population and equally small coffers, is taking a more limited approach, relying mostly on public education efforts.

That plan isn't without risks -- San Benito County sits next to the Central Valley, which the virus is expected to follow northward from its current spots in Southern California. But given their resources, county officials say public awareness is their best option.

"There would be risk whether we did mosquito abatement or not," said Dr. Elizabeth Falade, the county health officer. "We're all susceptible. If we put too much faith in abatement, we won't do the other things we need."

The virus first appeared in the United States in 1999 and has quickly traveled across the country. Birds, horses and humans are all vulnerable. In many people, infection usually causes no symptoms or only mild ones, including fever, headache and nausea. But some develop life-threatening illnesses that often affect the brain. In 2003, more than 9,800 Americans were diagnosed with some form of West Nile, and 264 of them died, according to federal health statistics.

Until West Nile's appearance, mosquito tracking in California usually had more to do with annoyance than disease. Of the state's 58 counties, 18 have no mosquito control, according to state health officials. Often, such counties aren't prime mosquito territory.

San Francisco hardly seems an ideal mosquito playground. The city's landscape is dominated by pavement, and many of its neighborhoods get swept by chilly fog in summer. But mosquitoes can still breed in water found in parks, vacant lots and construction sites, especially when the fog lifts in September.

San Benito County has the heat mosquitoes love, but many parts of the county are too dry to encourage them. Still, the insects can thrive in places such as the county's San Felipe Lake, and even breed in pools of water left by broken irrigation systems.

County environmental health workers said they've never gotten enough gripes about mosquitoes to warrant a mosquito control, or "vector control," agency.

"Right now, we rely heavily on education," said Robert Shingai, the county's director of environmental health. His group will be reminding landowners to keep their property free of standing water, which can collect in everything from old tubs and troughs to untended swimming pools. The county is also part of the state's network to collect and test dead birds for the virus.

Reb Monaco, a county supervisor, said mosquitoes have never been a big problem in the mostly rural part of the county he represents. But the board of supervisors might consider money for mosquito control if prompted by health officials, he said.

Veterinarians in the county have already been working to protect San Benito's horses. There is no vaccine to shield people against West Nile, but horses can be helped by a course of two shots given several weeks apart. Roger Bruce, a Hollister veterinarian, has been busy vaccinating horses all over the county.

"People have been very receptive," Bruce said. "It's a pretty dang good vaccine."

Bruce knows the dangers of West Nile all too well. His daughter in Nebraska caught the virus last year and spent 10 days in the hospital before she recovered.

"It was pretty scary for a while," he said. "We've been very lucky that West Nile didn't get into California until now."

Neighboring counties with vector control agencies say they will help out where they can. Pest control agencies in Santa Clara, San Mateo and Monterey counties will give out mosquito-eating fish to people with back-yard ponds in San Benito County or San Francisco.

In an emergency, those vector control groups might also step in with mosquito trapping or control, but their first priority is protecting their own counties.

San Benito's neighbors say the county's lack of mosquito control presents some health risk to people living in Santa Clara or Monterey counties, but those vector control groups are trying to limit it.

Kriss Costa, spokeswoman for Santa Clara County's vector control agency, said people living near the border of San Benito County and getting bothered by mosquitoes should phone her agency for help. Monterey County mosquito crews will also be keeping watch.

"It would be of help if San Benito had a proactive mosquito control program," said Peter Ghormley, manager and zoologist with the Northern Salinas Valley Mosquito Abatement District in Monterey County. "But we're already busy with prevention. We're preparing as though the virus could arrive any day."

State health officials, who are tracking West Nile's spread, said there may be money to help San Benito County if a health emergency flares. But for now, counties have to grapple with their own mosquito control.