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As weather heats up, mosquitoes reappear

A mosquito, a carrier for the potentially lethal

A mosquito, a carrier for the potentially lethal West Nile virus. Credit: Getty Images

With summerlike temperatures finally upon us, Long Islanders know what's on the horizon: mosquitoes, in greater numbers than those now buzzing around.

As the weather heats up, look for mosquito development to accelerate, said Jody Gangloff-Kaufmann, community coordinator of the New York State Integrated Pest Management Program in Babylon.

The thermometer hit the high 80s Thursday on Long Island, and the forecast calls for temperatures in the 80s at least into Friday and Saturday.

"Our cool spring has held back the emergence of huge numbers of mosquitoes, especially compared to last spring, which was warm and then hot," Gangloff-Kaufmann said.

As the temperatures "turn upward," a larger number of mosquitoes can be expected, she said.

And that means Long Islanders need to be even more vigilant about emptying standing water, where the insects breed.

Far more than an annoyance, certain mosquitoes, through their bites, spread West Nile virus to humans. Last year ranked as the second-worst in U.S. West Nile virus cases since the disease was first detected in this area in 1999, the Centers for Disease Control and Prevention said.

Nassau and Suffolk counties reported 14 human cases each last year, including one Nassau death. Nassau has already started mosquito surveillance at 42 traps countywide, said Mary Ellen Laurain, spokeswoman for the county health department. As of Tuesday, she said, "we're not seeing any real mosquito activity."

Suffolk begins its surveillance of about 45 traps next week, said Scott Campbell, lab chief of the county health department's arthropod-borne disease laboratory.

Last year, Nassau reported 81 mosquito samples testing positive for the virus, and Suffolk, 210.

Both counties have already started targeting mosquito larvae, with Suffolk launching Wednesday its low altitude helicopter pesticide spraying of area salt marshes.

Predicting the summer mosquito population is difficult, as specific weather conditions quickly "can change the activity level" of mosquitoes, said Bryon Backenson, director of the state Health Department's Vector Surveillance Unit, in a release.

On the one hand, rain can contribute to mosquitoes' breeding environment, experts say, but "flooding rains can wash away lots of mosquito larvae, especially from wetlands like our greenbelts on Long Island," Gangloff-Kaufmann said.

Hot, dry weather, leading to the evaporation of small amounts of standing water, can also mean fewer watering holes, bringing mosquitoes in proximity to infected birds, from which the insects pick up the virus, Campbell said.

West Nile virus activity

2012 Nassau: 14 human cases, 1 death

Suffolk: 14 human cases, no deaths

2011 Nassau: 16 human cases, 1 death

Suffolk: 4 human cases, no deaths

2010 Nassau: 57 human cases, 3 deaths

Suffolk: 25 human cases, 3 deaths