West Nile Virus Surveillance in Connecticut in 2000: An Intense Epizootic without High Risk for Severe Human Disease

• Main Authors: James Hadler, Randall Nelson, Tara McCarthy, Theodore Andreadis, Mary Jane Lis, Richard French, William Beckwith, Donald Mayo, Gary Archambault, Matthew Cartter
• Format: Article
• Language: English
• Published: Centers for Disease Control and Prevention 2001-08-01
• Series: Emerging Infectious Diseases
• Subjects: West Nile virus; birds; mosquito control; horses; seroprevalence; Connecticut
• Online Access: https://wwwnc.cdc.gov/eid/article/7/4/01-7406_article

In 1999, Connecticut was one of three states in which West Nile (WN) virus actively circulated prior to its recognition. In 2000, prospective surveillance was established, including monitoring bird deaths, testing dead crows, trapping and testing mosquitoes, testing horses and hospitalized humans with neurologic illness, and conducting a human seroprevalence survey. WN virus was first detected in a dead crow found on July 5 in Fairfield County. Ultimately, 1,095 dead crows, 14 mosquito pools, 7 horses, and one mildly symptomatic person were documented with WN virus infection. None of 86 hospitalized persons with neurologic illness (meningitis, encephalitis, Guillain-Barré-like syndrome) and no person in the seroprevalence survey were infected. Spraying in response to positive surveillance findings was minimal. An intense epizootic of WN virus can occur without having an outbreak of severe human disease in the absence of emergency adult mosquito management.