Nassau mosquito traps to gauge West Nile

At 42 secret locations throughout Nassau County, traps have been baited and now are set to capture their seasonal prey -- the first mosquitoes of summer.

The same baiting and waiting is under way in Suffolk County, but the level of secrecy is even tighter: Health department officials will not reveal the number of traps set there.

The element of mystery helps prevent tampering with the only way to gauge the abundance of mosquitoes -- and those carrying West Nile virus.

A bumper crop of mosquitoes is already in flight because of heavy rains this spring, but the outlook for West Nile is uncertain. Not all mosquitoes are capable of carrying the virus, and scientists and public health officials have only begun to learn how weather affects the spread of the virus.

If the summer is mild, then it's likely few, if any, people will contract the infection, experts say.

"Last year was one of the worst we ever had," said Dr. James L. Tomarken, Suffolk County's health commissioner, referring to human West Nile infections and the number of virus-laden mosquitoes trapped islandwide.

Extremely hot, dry conditions led to conditions ideal for West Nile's spread, Tomarken said.

"Those factors have not yet developed so far. So, hopefully, we will have a summer not like last year," he said.

Last year, experts say, was comparable to 1999, the year West Nile unexpectedly emerged in the Western Hemisphere. Queens and Long Island were the first areas hit in the United States before the virus fanned out.

Mosquitoes that breed in artificial containers are the ones that carry West Nile on Long Island, said Dr. Jorge Benach, director of Stony Brook School of Medicine's Center for Infectious Diseases.

West Nile virus, Benach said, is an animal pathogen harbored by birds. It is contracted by mosquitoes when they feed on fowl. People are inoculated with the virus when bitten by a female mosquito, which needs the blood meal to lay her eggs.

Bird blood is the preferred meal of female mosquitoes, but during heat waves birds take off for more abundant water sources, leaving people and their pets as the insects' choices, said Dr. Dickson Despommier, a microbiologist and emeritus professor of public health at Columbia University.

"To a mosquito, a bird represents a steak dinner," he said. "We're just a hot dog by comparison."

KEEP MOSQUITOS FROM BREEDING

Most bites by mosquitoes are caused by those breeding on your property or nearby. The insects require only a small amount of water to lay their eggs.

What you can do:

Dispose of used tires, a significant breeding site. Call your local landfill or public works department to find out how.

Drill holes in the bottoms of outdoor recycling containers.

Make sure roof gutters drain properly, and clean clogged gutters in spring and fall.

Turn over wading pools and wheelbarrows when not in use.

Change the water in birdbaths twice weekly.

Clean and chlorinate pools, outdoor saunas and hot tubs. Drain water from pool covers.

Use landscaping to eliminate standing water.

Sources: Nassau Department of Health; U.S. Centers for Disease Control and Prevention