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

Document Type

Article

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.