Seroepidemiologic Survey of Potential Pathogens in Obligate and Facultative Scavenging Avian Species in California

Straub, Mary H.; Kelly, Terra R.; Rideout, Bruce A.; Eng, Curtis; Wynne, Janna; Braun, Josephine; Johnson, Christine K.

In this study, we investigated exposure to avian pathogens in three species of birds that commonly scavenge on carrion: the California condor, which is restricted to areas in northern Mexico and the western United States [22] ; the turkey vulture (Cathartes aura), which is widespread throughout the Americas [23] ; and the golden eagle (Aquila chrysaetos), which is found mainly in western North America [24] . Unlike California condors and turkey vultures, which are obligate scavengers, golden eagles are facultative scavengers feeding on both carrion and live prey. The California condor is currently listed as critically endangered [25] and an intensive captive breeding program initiated in the 1980s [26, 27] has succeeded in the reintroduction of free-flying condor populations in California, Arizona and Baja California, Mexico [28] . Lead poisoning has been a primary cause of mortality in condors, and, other than WNV, infectious diseases have not been reported as an important cause of morbidity or mortality in this species [16, 29, 30] . Because WNV can be fatal in California condors, the captive and free-flying populations in California are vaccinated against this disease with a recombinant DNA vaccine [31, 32] being used prior to and during our study period. Serologic titers are measured annually in captive and free-flying condors and individuals are re-vaccinated as needed. Even with vaccination, the species is vulnerable to this disease as evidenced by the WNV-related death of a condor that had been vaccinated twice against WNV [16] .