West Nile Virus Infection in New York City: the Public Health Perspective

West Nile virus belongs to the Japanese encephalitis serocomplex of flaviviruses that includes the medically important St. Louis encephalitis, Murray Valley encephalitis, and Kunjin viruses. Most West Nile virus infections among humans are subclinical, with overt disease occurring in approximately 1 of 100 infections. The most common mosquito species in New York City, and many other northern urban areas, is Culex pipiens, a competent vector for a variety of mosquito-borne viral encephalitides. Viral meningitis and encephalitis are 2 of 70 reportable diseases or conditions in New York City and New York State. In recent years the New York City Department of Health has been actively promoting the importance of physician reporting of unusual disease clusters or manifestations because of concerns about both the early detection of new or reemerging infectious diseases and the threat of bioterrorism. The media was likely the most effective conduit for informing the public about the disease and the city's public health response. The ongoing public health response to the West Nile virus outbreak included active surveillance to fully define the geographic extent of the outbreak and to evaluate the need for additional mosquito control measures. Public health messages regarding protective measures for avoidance of West Nile virus infection and West Nile disease surveillance should therefore be particularly targeted at older persons.