State Health Commissioner Antonia Novello said the mosquitoes that tested positive were from Westchester and Suffolk counties, outside the city.
But two birds with the disease have been found in New York City for the first time this year, the New York State Health Department said Monday. Birds, like humans, get the virus from mosquitoes. No cases of human infection have been detected this year.
The New York City birds - two crows found dead in Staten Island - were among four birds added Monday to this year's list of West Nile victims. The other two were from Clarkstown in Rockland County. A total of 19 birds from the suburbs in New York and New Jersey had earlier been found infected.
The Staten Island crows were the first sign of West Nile this year in New York City, which was the epicenter of the outbreak last year.
In the most serious cases, West Nile can cause an infection resulting in encephalitis, or swelling of the brain. Elderly people or those with weakened immune systems are most at risk.
Suffolk County planned to begin an insecticide-spraying program Tuesday. Westchester County officials made no immediate decision about spraying.
City officials said they planned to spray from trucks late Wednesday night and early Thursday in the sections of Staten Island where the two infected birds werfound.
Suffolk County Health Services spokeswoman Millie Svatek said although the county's Department of Public Works has been regularly spraying for mosquitoes even years before West Nile was detected in the area, the urgency of the spraying now becomes more important.
"This is different. This spraying is in order to prevent or reduce the transmission of this disease," Svatek said.
Applications to spray were scheduled for Tuesday evening in Lindenhurst, West Babylon and Point O' Woods on Fire Island.
The findings were announced as scientists from the Centers for Disease Control and Prevention and the U.S. Geological Survey were working in the region to assess existing preventive measures and to try some new ones - like trapping house sparrows to test them for antibodies.
Landrigan said the CDC was working in Westchester on Monday, and Geological Survey spokesman Butch Kinerney said his agency was working in Bergen County, N.J.
Novello said she had contacted the CDC "to discuss a multistate, regional approach to prepare a plan of action to fight the disease."
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