Valley's rain, empty homes raise mosquito threat | The Fresno Bee

San Joaquin Valley health officials are bracing for what already is shaping up to be a bad mosquito season -- and potentially a severe West Nile virus year -- as spring rains and foreclosures give the bugs plenty of places to multiply.

"We definitely have our work cut out for us," said Michael Alburn, manager of the Delta Vector Control District in Visalia.

Even drained swimming pools are holding several feet of water deposited by recent heavy rains.

And in the shaky economy, people continue to lose homes to foreclosure or can't afford to keep pool filters running. They leave thousands of abandoned and neglected pools full to save them from damage, but the stagnant water creates perfect nests for female mosquitoes.

Knocking out mosquitoes is crucial to preventing West Nile virus. The virus attacks the central nervous system and is spread by mosquitoes that feed on infected birds.

Since 2005, there have been 14 West Nile virus-related deaths and 288 infections in the Valley. Last year, Fresno and Merced counties each reported one death.

So far this year, no human cases of the virus have been reported in California, but it's early in the season, and mosquito-control and state health officials have their guard up.

For the last few years, the mosquito fight has focused on abandoned and neglected backyard swimming pools because they are the biggest breeding grounds in urban areas.

It's no different this year.

An aerial survey of Visalia indicates there will be more pools to stock with mosquito-eating fish. Last year, workers in Visalia treated about 1,000 pools. Homeowners are not charged for the fish or the service.

The same conditions hold for the Fresno Mosquito and Vector Control District. Manager Tim Phillips had hoped for less pool work this year, "but we haven't seen that yet," he said. His office has a list of 1,325 pools to inspect and possibly treat. By contrast, in 2006, workers treated 400 pools, he said. "Then it went to 900 and to 1,000 and to 1,300 -- and that's where we are now."

The Consolidated Mosquito Abatement District, which covers most of Clovis, has about 900 pools identified from last year. And calls about suspected breeding pools keep coming, said Manager Steve Mulligan.

This year, Mulligan said, more people who have bought foreclosed homes are calling for help. The pools are in disrepair, and new homeowners cannot yet afford to fix them, he said.

Wendy Christian requested mosquitofish last week at her northeast Fresno home. When she bought the house in July, the pool had been drained. She can't fill it until it's repaired.

Christian, 45, tries to keep the pool empty. But that has been a never-ending battle against the weather. "We'll drain it -- and it rains," she said.

The last couple of weeks, several feet of water collected in the deep end, and she called Consolidated. "We love to spend time in our backyard, but we're being eaten alive by mosquitoes," Christian said.

It's difficult to predict exactly how severe West Nile virus will be this spring and summer, state health officials say. But there will be more mosquito breeding habitats than typical because of the winter rains.

As the snow pack melts, rivers in the Valley will swell, creating new places for mosquitoes to nest. And federal officials have refilled the dry parts of the San Joaquin River as part of a vast restoration program.

The communities of Kerman, Tranquility and Mendota could be swatting more mosquitoes than usual, said Elizabeth Cline, manager of the Fresno Westside Mosquito Abatement District.

Already, "tree hole" mosquitoes have been busy. These mosquitoes like to make nests in hollowed logs along riverbeds, Cline said. They don't carry West Nile virus, but they do carry heartworm, a parasite that is potentially deadly to dogs and cats, she said.

All dogs and cats in the Valley should be given a preventive medication for heartworm, said Cheryl Waterhouse, a Fresno veterinarian.

Horses are susceptible to West Nile virus, and a vaccine is available for them, mosquito-control officials said. But there's no vaccine for humans. People should wear protective clothing or mosquito repellent to ward off bites.

As warm weather arrives, it will kick mosquito breeding season into high gear.

"Mosquitoes develop faster when the weather is warmer," said Vicki Kramer, chief of the Vector-Borne Disease Section at the California Department of Public Health.

Kramer reminds people to report dead birds and squirrels to the state health department. The deaths can signal that West Nile virus is active in an area, she said. The state tracks the reports -- regardless of whether the birds or squirrels are picked up for testing, she said.

Mosquito-control officials said people should report abandoned and neglected pools, and survey their backyards for anything that can hold water -- wheelbarrows, buckets, old tires.

"Everything that's holding water certainly is growing mosquitoes right now," said Phillips of the Fresno mosquito control district.