By Scott Taylor,Staff Writer

LEWISTON – Maine has 45 species of mosquitoes, but Kim Foss is only interested in three or four.

She’ll hunt them down this summer. Then she’ll trap, classify and test them for signs of the deadly West Nile virus.

So far, she’s found no signs of the virus, but she knows it’s early.

“The spring species, the mosquitoes out now, tend to be more annoying than dangerous,” she said. “Later in the summer, it’s a different matter.”

Foss is teaming up with state health officials to track the mosquito-borne virus in Lewiston. She works for York-based Municipal Pest Management Services Inc., a private company that specializes in tracking and killing mosquitoes and other pests throughout New England, with her salary paid from a Centers for Disease Control grant to the state health department. Maine Medical Center is involved in similar work in Portland, while the University of Maine is doing the same thing in Bangor.

So far, Maine has been spared human cases of the virus, although statewide testing has turned up hundreds of dead birds infected with West Nile.

The virus spreads in a cycle, from bird to bug to human. Foss’ job is to track the virus as it spreads between bird and bug, the early stages of the cycle.

Her bait is a sour-smelling brew made of fermenting hay and water. She keeps a huge sealed jug of the stuff in the back of her car.

Female mosquitoes, fresh from feeding and full of blood, seek out the stinky, nutrient-rich water as a place to lay their eggs. The trap is a small plastic basin with a tube in the middle topped by a fan and a net. Mother mosquitoes, trying to lay their eggs in the water, get sucked up the tube and stuck in the net. Foss takes her catch, sorts the mosquitoes by type and tests them for the virus.

She concentrates her traps downtown, between streets and buildings. The mosquitoes she’s after are born in catch-basins under the streets. They feed almost exclusively on downtown birds such as pigeons and crows – any bird walking down the street.

Suburban bugs

The virus spreads when infected birds migrate out of the city and get bitten by other kinds of mosquitoes, the kinds that also feed on people. They breed in more suburban settings – roof gutters, neglected water dishes and old tires.

Once those suburban mosquitoes feed on an infected bird, they can spread the virus to humans.

It hasn’t happened yet in Maine.

More than 16,000 people in the United States have tested positive for the disease since 1999. Maine is the only state east of the Mississippi that has not had a human victim.

In New Hampshire, the cities respond by poisoning the mosquito larvae. Corn, laced with a special bacteria, is thrown into the catch basins. Mosquito larvae eat the corn, and the bacteria gives them a deadly case of indigestion.

That’s the best way to handle the problem. It kills the mosquitoes responsible for spreading West Nile virus from bird to bird, interrupting the cycle.

“If it can’t get to the birds, it can’t get to humans,” Foss said.

She wants Maine municipalities to adopt similar plans.

“Most people think controlling mosquitoes means a truck driving along the streets spraying a pesticide,” she said. “This is better, attacking the disease before it becomes a problem.”

Ruining the mosquitoes’ habitat is the best bet for individual control. She urges homeowners to clean out murky drains and gutters, kick over anything that collects standing rainwater and change water dishes every few days.

The state also urges people to cover up and put on a DEET-containing insect repellent.