The Buzz About Mosquitoes Is Getting Louder

Orange County officials report a 54% increase in complaints by residents who say mosquitoes are appearing in greater numbers around their houses and generally causing problems--such as biting the adults and children who live there.

“Most people don’t think there’s any problem with mosquitoes--unless they get bit, and bit a lot, and then there’s a big problem,” said Jim Francisco, educational coordinator for the Orange County Vector Control District.

Francisco said this week that vector control officials recorded 7,712 complaints involving mosquitoes so far this year, more than the 7,023 received in all of 1996.

“It surprised us,” he said. “We don’t believe there’s a crisis . . . a lot of the increase may be due to public awareness.”

Another reason may be rainfall. Mosquitoes thrive in rain, the experts say, and through Monday, rainfall in Orange County was already more than two inches greater than during all of 1996.

“We recorded 11.33 inches of rain last year,” said Mel Newman, environmental resources specialist for Orange County, “and so far this year, we’ve had 13.53 inches of rain.”

For some reason, the mosquito figures appear to be proportionately higher in Orange County than Los Angeles County, and San Diego reports little change.

Los Angeles County has six vector control districts, but the largest, headquartered in Santa Fe Springs, reports an increase similar to that of Orange County: 899 complaints involving mosquitoes so far this year, compared to 765 all of last year. Officials there say the other five districts reported similar increases.

But in San Diego, Moise Mizrahi, spokesman for the San Diego County Vector Control District, reports mosquito activity “almost exactly the same” this year as last, and it wasn’t bad either year.

Officials often worry more about the types of mosquitoes living in an area. In other words, specific breeds are a greater concern than quantity. Their biggest concern is what some officials call “the big E”--encephalitis, otherwise known as sleeping sickness or brain fever. Mosquitoes can also cause yellow fever and malaria.

Southern California endured an outbreak of encephalitis in 1984, resulting in 26 illnesses and six deaths, including two in San Diego and one in Orange County. No cases have been reported this year.

Encephalitis is caused by a virus transmitted by mosquitoes, which can also transmit malaria. San Diego County endured mosquito-borne malaria scares in 1986 and 1988, Mizrahi said, noting that so far this year, no such serious diseases have been reported.

Partly in an effort to detect such diseases, vector control workers in all three counties trap mosquitoes to gather a variety of data.

“We target the disease vectors first, then move on to the nuisance breeds,” Mizrahi said.

To avoid problems with the bloodsucking insects, officials in Orange County have been spraying gutters with repellent every day this summer. In addition, vector control officials last month dumped 10,000 mosquito fish into stagnant bodies of water throughout the county.

The fish devour the mosquito eggs before the insects hatch.

Though Southern California is relatively free of the more serious mosquito scares--Deep South states such as Florida, for instance, have to be far more vigilant--at least 21 species have been identified in Orange County alone, officials say.

The good news in Orange County is that vector control officials just tested the bird population for mosquito bites and found a remarkably low incidence of mosquito-born disease, Francisco said.

But that doesn’t mean the bites don’t persist.

“Unfortunately, the bites are worse in areas near the coast,” Francisco said, “and there’s nothing we can do about that. Mosquitoes like the water . . . and so do people. So, if you go to the beach, sooner or later, a mosquito’s going to bite you. And there’s nothing much we can do about it here. Mosquitoes are a fact of life.”

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Profile of a Pest

Mosquitoes are about a quarter-inch long with slender bodies and narrow wings. A long, narrow “beak” is used to siphon plant juices and blood from mammals. The insects breed year-round, and a female can bear about 3,000 young in a lifetime. Eggs grow into adults in about 10 days, passings through four stages, each marked by physical transformation:

Egg raft: Groups of 100-300 eggs laid at one time on water’s surface; eggs usually hatch in two to three days

Larva: Lives underwater; molts four times in four to 10 days, then changes into pupa.

Pupa: Within two to four days it swims to the surface, where adult emerges from pupal skin.

Adult: Males live from seven to 10 days; females can live longer in protected environments.

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PREVENTION TIPS

* Remove standing water from yard

* Cover or turn over empty containers

* Clean swimming pools, spas, ornamental ponds daily

* Add mosquito-eating fish to ponds, channels

* Spray breeding areas with insecticide

* Fill in unused ornamental ponds with sand or dirt

Source: Times reports