Declining Mortality in American Crow (Corvus Brachyrhynchos) Following Natural West Nile Virus Infection

Authors

Lisa M. Reed, Center for Vector Biology, Rutgers University, 180 Jones Avenue, New Brunswick, NJ 08901Follow
Michael A. Johansson, Division of Vector-borne Infectious Diseases, Centers for Disease Control and Prevention
Nicholas Panella, Division of Vector-borne Infectious Diseases, Centers for Disease Control and PreventionFollow
Robert McLean, USDA-APHIS-Wildlife ServicesFollow
Terry Creekmore, Wildlife Division, Wyoming Game and Fish
Rose Puelle, Public Health Preparedness, Public Health, P.O. Box 2900, Hunterdon County, NJ 08822
Nicholas Komar, Division of Vector-borne Infectious Diseases, Centers for Disease Control and Prevention

Date of this Version

2009

Comments

Published in AVIAN DISEASES 53:458–461, 2009.

Abstract

The American crow (Corvus brachyrhynchos) is known to suffer 100% mortality from infection with the New York 1999 strain of West Nile virus (WNV). Following the initial detection of WNV in North America in 1999, we measured prevalence of WNV-reactive antibodies (‘‘seroprevalence”) in free-ranging American and fish crows (Corvus ossifragus) of central New Jersey after each transmission season through 2005. In 2002, seroprevalence in American crow juveniles increased to 14% from the 5% of the previous year, potentially indicating increased survival in this species. Using the annual seroprevalence measurements and the number of human West Nile neuroinvasive disease cases as a surrogate for WNV transmission intensity, we developed a model to estimate the annual WNV-associated mortality rates among both of these crow species. Our model supports the hypothesis that mortality is changing over time; the WNV-associated mortality rate declined over time by 1.5% for American crow and by 1.1% for fish crow. The probability that the trend in mortality was negative was 90% for the American crow and 60% for the fish crow.