Clinical Findings of West Nile Virus Infection in Hospitalized Patients, New York and New Jersey, 2000

West Nile VirusFollowing the emergence of West Nile (WN) virus in New York in 1999, state and local health departments in the eastern United States, in conjunction with the Centers for Disease Control and Prevention (CDC), established surveillance systems for detecting WN virus activity (1).New York City and New Jersey established active and enhanced passive surveillance systems for human disease that encouraged physician, infection control practitioner, and laboratory reporting of suspected cases and provided testing for WN virus.This report details the clinical characteristics of 19 hospitalized human cases that occurred during the summer and fall of 2000; all patients resided in either New York City (NYC) or New Jersey. MethodsEnhanced surveillance for WN virus human disease in New York and New Jersey during 2000 was instituted to facilitate timely reporting of viral meningoencephalitis and to ensure rapid and accurate laboratory testing for WN virus.In NYC, encephalitis and viral meningitis are reportable conditions.From May to October 2000, the following measures were implemented by the NYC Department of Health to supplement existing passive surveillance: 1) Enhanced passive surveillance-To encourage physician reporting citywide, information on WN virus reporting and testing procedures was widely disseminated to the medical community through invited presentations by departmental medical staff, an agency publication mailed to >65,000 health-care providers, and biweekly broadcast facsimile and e-mail alerts to all NYC hospitals; 2) Hospital-based active physician surveillance-Neurologists, infectious disease consultants, intensive-care physicians, and chief medical residents at 18 sentinel NYC hospitals were called every 2 weeks to ascertain potential cases meeting clinical criteria; 3) Hospital-based active laboratory surveillance-Laboratories at 12 sentinel NYC hospitals submitted all cerebrospinal fluid (CSF) specimens suggestive of a viral cause for WN virus testing at the NYC health department (CSF with negative Gram stain and culture with either a CSF leukocyte count >5/mm 3 or protein >40 mg/dL).A special unit was established within the Communicable Disease Program of the NYC Department of Health to implement these additional surveillance activities.This unit ensured that all suspected cases were prioritized for next-business-day specimen collection and transportation to the city's Public Health Laboratories for WN virus testing.In New Jersey, bacterial meningitis and encephalitis are reportable to the New Jersey Department of Health and Senior Services (NJDHSS).Active, hospital-based surveillance by infection control practitioners targeted patients admitted with the diagnoses of aseptic meningitis or encephalitis in 42 hospitals in six northern counties.Passive surveillance was enhanced through the distribution of reporting protocols, surveillance criteria, and WN virus educational materials to the medical community.