Avian trichomonosis in spotted owls (Strix occidentalis): Indication of opportunistic spillover from prey.
Avian trichomonosis, caused by the flagellated protozoan parasiteTrichomonas gallinae, has variable pathogenicity among bird species ranging from asymptomatic infections to severe disease periodically manifesting in epidemic mortality. Traditionally, columbids are identified as highly susceptible to infection with occasional spillover into raptors that prey on infected birds. We identified avian trichomonosis in two dead California spotted owls (Strix occidentalis occidentalis) and three dead northern spotted owls (S. o. caurina) in California during 2011-2015; infection was confirmed in four owls by PCR. Pathologic lesions associated with trichomonosis in the owls included caseonecrotic lesions of the upper palate accompanied by oropharyngitis, cellulitis, myositis, and/or sinusitis. Spotted owls are known to mainly feed on small mammals; therefore, the source of infection as well as the significance of the disease in spotted owls is unclear. These owl trichomonosis cases coincided temporally and spatially with three trichomonosis epidemics in band-tailed pigeons (Patagioenas fasciata monilis). The same parasite,T. gallinaesubtype A2, was isolated from the spotted owls and band-tailed pigeons, suggesting the owls became infected when opportunistically feeding on pigeons during mortality events. Avian trichomonosis is an important factor in the decline of the Pacific Coast band-tailed pigeon population with near-annual mortality events during the last 10 years and could have conservation implications for raptor species at risk, particularly those that are facing multiple threats.
Wildlife Investigations Laboratory, California Department of Fish and Wildlife, 1701 Nimbus Road, Suite D, Rancho Cordova, CA 95670, United States.
Krysta H
KH
Rogers
Karen C. Drayer Wildlife Health Center, School of Veterinary Medicine, University of California, Davis, 1089 Veterinary Medicine Drive, Davis, CA 95616, United States.
Yvette A
YA
Girard
California Animal Health and Food Safety Laboratory, University of California, Davis, 620 West Health Sciences Drive, Davis, CA 95616, United States.
Leslie
L
Woods
Karen C. Drayer Wildlife Health Center, School of Veterinary Medicine, University of California, Davis, 1089 Veterinary Medicine Drive, Davis, CA 95616, United States.
Christine K
CK
Johnson
Avian trichomonosis; Band-tailed pigeon; Columbid; Epidemic; Fe-hydrogenase; ITS1/5.8S/ITS2; Spotted owl; Trichomonas gallinae