Arthropod-Borne Disease Program, New York State Department of Health, Albany, New York 12237, USA
Address for correspondence: Dennis J. White, Ph.D., Director, Arthropod-Borne Disease Program, New York State Department of Health, Corning Tower Building, Empire State Plaza, Albany, NY 12237. Voice: 518-474-4568; fax: 518-473-1708.
djw05{at}health.state.ny.us
West Nile virus (WNV) was detected in the metropolitan New York
City (NYC) area during the summer and fall of 1999. Sixty-two
human cases, including seven fatalities, were documented. The
New York State Department of Health (NYSDOH) initiated and implemented
a statewide mosquito and WNV surveillance system. We developed
a WNV response plan designed to provide local health departments
(LHD) a standardized means to begin to assess basic mosquito
population data and to detect WNV circulation in mosquito populations.
During the 2000 arbovirus surveillance season, local health
agencies collected 317,676 mosquitoes and submitted 9,952 pools
for virus testing. NYSDOH polymerase chain reaction (PCR) testing
detected 363 WNV-positive pools. Eight species of mosquitoes
were found to be infected. Of the 26 counties conducting mosquito
surveillance, WNV-positive mosquitoes were detected only in
NYC, on Long Island, and in four counties in the lower Hudson
River valley region. LHD larval surveillance provided initial
or enhanced mosquito habitat location and characterization and
mosquito species documentation. Adult mosquito surveillance
provided LHD information on species' presence, density, seasonal
fluctuations, virus infection, minimum infection ratios (MIR)
and indirect data on mosquito control efficacy after larval
or adult control interventions. Collective surveillance activities
conducted during 1999 and 2000 suggest that WNV has dispersed
throughout the state and may affect local health jurisdictions
within NYS, adjacent states, and Canada in future years. Vector
surveillance will remain a critical component of LHD programs
addressing public health concerns related to WNV.
