Strategies to assess and reduce risk associated with disease agents in wild animals must be based upon thorough knowledge of the epidemiology of the disease agent, specific local information, and other factors. Risk evaluation and management efforts will involve organizations with differing expertise and cooperation will be essential between wildlife management, public health, and domestic animal health agencies. Risk reduction strategies may be based upon manipulation of the disease agent, the host, the environment, and/or human activities. Management of human activity, particularly the promotion of biosecurity, may be the most efficient strategy because other measures are more difficult and expensive. The science of risk assessment and disease management in wildlife is growing and evolving as new situations arise and as new methods are developed to meet the needs of wildlife resource, animal agriculture, and public health interest groups.

Trichomonas gallinae is a ubiquitous flagellated protozoan parasite, and the most common etiologic agent of epidemic trichomonosis in columbid and passerine species. In this study, free-ranging Pacific Coast band-tailed pigeons (Patagioenas fasciata monilis) in California (USA) were found to be infected with trichomonad protozoa that were genetically and morphologically distinct from T. gallinae. In microscopic analysis, protozoa were significantly smaller in length and width than T. gallinae and were bimodal in morphology. Phylogenetic analysis of the ITS1/5.8S/ITS2, rpb1, and hydrogenosomal Fe-hydrogenase regions revealed that the protozoan shares an ancestor with Trichomonas vaginalis, the sexually-transmitted agent of trichomoniasis in humans. Clinical and pathologic features of infected birds were similar to infections with T. gallinae. Evidence presented here strongly support taxonomical distinction of this parasite, which we hereby name Trichomonas stableri n. sp. This work contributes to a growing body of evidence that T. gallinae is not the sole etiologic agent of avian trichomonosis, and that the incorporation of molecular tools is critical in the investigation of infectious causes of mortality in birds.