Discovery of New, Pathogenic Protozoans Cultured from Free-Ranging Mockingbirds (Mimus polyglottos), House Finches (Carpodacus mexicanus), and Corvids: Genotyping, Prevalence, and Clinicopathologic Characteristics
This study documents newly discovered trichomonads associated with morbidity and mortality in free-ranging house finches (Carpodacus mexicanus), mockingbirds (Mimus polyglottos), and corvids [Western scrub jay (Aphelocoma californica), American crow (Corvus brachyrhynchos), common raven (Corvus corax)] in northern California. Sensitivity and specificity of wet mount screening in house finches were >95% (via comparison to InPouch TF™ culture kits, BioMed Diagnostics, White City, Oregon 97503 USA). Prevalence of infection on admission to a wildlife hospital ranged between 0.34–6.25%. Clinicopathologic findings and response to treatment were highly variable between species. Less than 30% of infected individuals displayed clinical signs that increased suspicion of trichomonad infection. These signs included sticky material on head or beak, caseous oral lesions, and ocular lesions in house finches; caseous sinusitis and conjunctivitis or neurologic signs in mockingbirds; and ocular and oral lesions in corvids. Case fatality ratio was >80% in house finches, scrub jays, and crows, 37.5% in mockingbirds, and 0% in ravens. Trichomonads were not detected in any surviving house finches (n=3) or corvids (n=3) after treatment with carnidazole (20–30 mg/kg PO SID for 5–10 days; Wildlife Pharmaceuticals, Inc., Fort Collins, Colorado 80522). Identical treatment resolved clinical signs but did not clear trichomonad organisms from mockingbirds. DNA sequencing found that the house finch and corvid organism was closely related to Trichomonas gallinae, while the mockingbird organism was genetically distinct from all other sequenced trichomonads. Wet mounts are a reliable and inexpensive method of screening for trichomonad infection in these species.