Print version ISSN 0042-9686
Bull World Health Organ vol.78 n.9 Genebra Jan. 2000
West Nile virus detected in mosquitoes in Central Park
Local health authorities throughout the New York City area have stepped up surveillance and ordered more spraying of neighbourhoods with insecticide as more birds infected with West Nile virus are identified and as more mosquitoes carrying the virus are found.
In July, the nations most famous urban park Central Park was closed and a New York Philharmonic outdoor concert postponed after city officials announced that they had found mosquitoes infected with West Nile virus in Central Park and would spend the night administering insecticide to the 843-acre park.
Brooklyn and Queens have been added to the areas needing spraying with insecticides. New York City recently escalated its efforts further to combat the problem when Mayor Rudolph Giuliani said he would ask the state for permission to start aerial spraying on Staten Island. New York City Department of Health spokesman Erich Giebelhaus says the city is in talking stages with the New York State Department of Environmental Conservation, from which permission must be obtained to spray larvicide. The city wants to target some areas, like wetlands, that would be inaccessible to ground spraying, Giebelhaus says.
Nassau County announced that for the first time this summer two dead birds infected with the virus had been found in two communities in the Long Island area. Nassau joins Rockland, Suffolk, Westchester, Staten Island, and Queens as well as communities in North Jersey and Connecticut that have reported similar findings.
In addition, there are signs that the virus has spread out of the New York metropolitan area to other East Coast cities. Boston recently reported that two birds found there had tested positive for the virus. Massachusetts is the fifth state where the mosquito-borne virus has spread since it was first detected in North America last August and sent scientists along the East Coast scrambling to monitor its transmission.
Officials continue to stress that, as of yet, no humans have been diagnosed this year with the virus, which can cause encephalitis, a potentially fatal disease that may lead to swelling of the brain and damage to the central nervous system. The West Nile virus killed seven people and sickened another 62 last summer, but is considered by experts to be a mild pathogen.
The origins of the infected crows in the Boston area remain a mystery, but city and state officials appear unwilling to take any chances. Low concentrations of resmethrin, a synthetic pesticide, were sprayed in Boston and around three vacation areas popular with tourists.
West Nile virus has been commonly found in humans, birds and other vertebrates in Africa, Eastern Europe, and parts of Asia, but had not been reported in the western hemisphere until recently. The origin of the virus found in the United States is not known. According to the US Centers for Disease Control and Prevention in Atlanta, mosquitoes are infected when they feed on infected birds. After an incubation period of 10 to 14 days, mosquitoes can transmit the West Nile virus to humans and animals.