RESUMO
Forty-two Trichomonas gallinae isolates were molecularly characterized to determine whether isolates differed in genetic sequence of multiple gene targets depending on host species or geographical location. The 5.8S ribosomal RNA (rRNA) and flanking internal transcribed spacer (ITS) gene regions were amplified by polymerase chain reaction, and the sequences were analyzed phylogenetically. The results of the sequence analysis strongly suggest at least 2 species may exist within the T. gallinae morphologic complex. Based on ITS sequences, one group demonstrated high nucleotide identity to the 3 T. gallinae sequences available in GenBank, whereas the second group was more closely related to T. vaginalis (98%) than to T. gallinae (92%). Two common ground-dove (Columbina passerina) isolates shared a 95% identity with T. vaginalis and a 92% identity with T. gallinae and T. tenax. Sequence analysis of both the 18S rRNA and alpha-tubulin genes from a subset of the isolates supports the 5.8S-ITS sequence results. All of the T. vaginalis-like isolates originated from Arizona, California, or Texas, whereas T. gallinae isolates were found in all sampled states. Both T. vaginalis-like and T. gallinae isolates were involved in trichomoniasis outbreaks in California and Arizona.
Assuntos
Doenças das Aves/parasitologia , Columbidae/parasitologia , Tentilhões/parasitologia , Falcões/parasitologia , Tricomoníase/veterinária , Trichomonas/genética , Animais , DNA de Protozoário/química , DNA Ribossômico/química , DNA Espaçador Ribossômico/química , Filogenia , RNA de Protozoário/genética , RNA Ribossômico 18S/genética , RNA Ribossômico 5,8S/genética , Alinhamento de Sequência/veterinária , Trichomonas/classificação , Trichomonas/isolamento & purificação , Tricomoníase/parasitologia , Tubulina (Proteína)/genética , Estados UnidosRESUMO
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.