West Nile Virus found in Westchester

Frozen mosquitoes on a slide. Only female mosquitoes will be sent to the New York State lab to be analyzed because only the females eat human blood. Photos courtesy Caren Halbfinger

Frozen mosquitoes on a slide. Only female mosquitoes will be sent to the New York State lab to be analyzed because only the females eat human blood. Photos courtesy Caren Halbfinger

By CONOR MCKOY
As the summer draws to a close, Westchester residents are once again at risk of contracting the West Nile Virus.

According to the West-chester County Department of Health, several mosquitoes have tested positive for West Nile Virus in the county. The positive pool came from New Rochelle, which is one of the 10 sites at which the Department of Health collects mosquitoes for testing.

So far this year, there have been 137 batches of mosquitoes tested with only one positive batch reported.

The reports of West Nile in Westchester came around the same time last year in late August and it wasn’t
until September that the only two human cases of West Nile were reported.

In July, New York City reported its first positive tests for West Nile. Since then, the New York City Department of Health and Mental Hygiene has tested 2,108 batches of up to 50 mosquitoes and reported 67 positive batches for West Nile Virus.

As of press time, there aren’t any reported human cases of the virus in either New York City or Westchester.

According to the West-chester Commissioner of Health Sherlita Amler, the reports of West Nile aren’t unusual around this time of year and residents shouldn’t worry.

John Ruggiero, a sanitarian who helps run the Westchester mosquito lab, collects mosquitoes from a Centers for Disease Control light trap.

John Ruggiero, a sanitarian who helps run the Westchester mosquito lab, collects mosquitoes from a Centers for Disease Control light trap.

“This is the time of year when we typically start to identify mosquitoes that carry West Nile Virus in West-chester,” Amler said. “While it should not be a major cause for concern, it would be prudent for residents to use
repellents when outdoors from dusk to dawn to avoid mosquito bites altogether.”

Not only are county health officials advising citizens to take precaution, but the Department of Health also has taken measures against the spread of West Nile. Unlike other counties, Westchester chooses not to spray pesticides but looks for other means to deal with mosquitoes.

Since May, workers have been systematically surveying the county, checking for pools of stagnant water where mosquitoes might breed.

“[Westchester County] only applies larvicide to those that hold or have the potential to hold standing water,” Caren Halbfinger, Westchester Department of Health director of public health information and communications, said.

According to Halbfinger, the county then uses its least toxic, most effective larvicide to prevent larvae from developing into full grown, virus-carrying mosquitoes.

Westchester also offers minnows to citizens with ponds around their homes. Minnows, which are small, fresh water fish, feed on mosquito larvae and pupae and offer a natural way to reduce the threat of West Nile. In the past two years, the county has given away over 200 pounds of minnows to the public.

In addition to reducing the mosquito population, West-chester County captures and tests mosquitoes in the area. The county uses two types of traps to lure mosquitoes. The first is a Centers for Disease Control light trap, which uses light and dry ice to emit carbon dioxide. The carbon dioxide fools the mosquitoes into thinking the trap is a human and lures them in. The other trap is called a gravid trap, which attracts pregnant, or gravid, mosquitoes in with liquid bait.

The traps are checked on a daily basis and the captured mosquitoes are sent to Westchester’s mosquito lab, located in a building at the county airport in Harrison. The mosquitoes are placed in a freezer, frozen, and then
examined under a microscope. The females are sent to the state lab for viral testing since females are the only mosquitoes that feed on humans and animals. At the state lab, the mosquitoes are tested for West Nile and the results are sent back to Westchester’s Department of Health.

The county Department of Health has recommended residents take precautions against contracting the virus. It’s recommended that citizens help eliminate breeding grounds by clearing their property of stagnant water. To prevent mosquito bites, the Department of Health suggests using bug spray, wearing long-sleeve shirts, long pants and reducing time outside when mosquitoes are active and feeding.