Serosurveys for West Nile Virus Infection--New York and Connecticut Counties, 2000

Abstract

In 2000 21 persons with acute illness attributed to West Nile virus (WNV) infection were reported in several counties in New York. Because ill persons represent only a fraction of the persons who are infected many more persons probably were infected in 2000. To determine the prevalence of recently acquired WNV infection and associated risk factors for infection random household cluster serosurveys were conducted in Staten Island (New York City) portions of Fairfield County (Connecticut) and Suffolk County (New York) during October and November 2000. All three areas had intense WNV epizootics as determined by avian mortality and mosquito surveillance systems. This report summarizes the preliminary results of this survey and indicates that in areas with intense epizootic WNV activity asymptomatic or mildly symptomatic human infections can occur.