In residential areas, the public is urged to assist in this prevention effort by eliminating areas of standing water. This includes unclogging roof gutters, emptying and or chlorinating unused swimming pools, changing water in bird baths at least once a week, and discarding old tires, buckets, and any unused containers that may hold water and serve as mosquito breeding sites. For areas of standing water that cannot be eliminated, larvicides can be placed in water to prevent mosquito eggs from hatching into adult mosquitoes. The City will place larvicide in catch basins citywide early in the spring, before mosquito eggs are present, concentrating on areas where the West Nile transmission occurred in 1999. This will be repeated when mosquito larvae are detected.
Mosquito larvae live exclusively in water.
West Nile encephalitis is an infection of the brain caused by West Nile virus, a mosquito-borne virus commonly found in Africa, West Asia, and the Middle East. It is closely related to the St. Louis encephalitis virus found in the United States. Persons greater than 50 years of age have the highest risk of severe disease. Prior to August 1999, West Nile virus had never been reported in the United States. Among New York City residents there were 46 cases, including four deaths.