Investigation of Trichomonas gallinae in passerines

Abstract

Trichomoniasis, caused by the protozoan Trichomonas gallinae, has as main hosts birds of the Columbidae family, which have a high prevalence of the protozoan without manifesting the disease. The continuous growth of the pigeon population and its cosmopolitan nature mean that today there is a worldwide distribution of this species, being responsible for the distribution and maintenance of the prevalence of trichomoniasis in almost the entire world. The transmission of the disease may be by direct contact, or indirect, through food or water. This indirect route is the reason why such a wide range of bird orders can be infected, very different from columbids such as falconiformes, strigiformes, passerines, piciformes, psittaciformes, gruiformes, galliformes or anseriformes. Thus, the objective of this study was to evaluate the presence of T. gallinae in passerines received at a Wild Animal Screening Center. In order to carry out this study, 300 birds of the order Passerine corresponding to 23 different species were analyzed, received at the Wild Fauna Rehabilitation Center (NURFS) of the Federal University of Pelotas (UFPel), in different seasons of the year between the months of March to October 2021. Samples of swabs from the oropharynx were collected from all individuals, the material was immediately placed in a falcon tube containing Trypticase-Yeast Extract-Maltose (TYM) culture medium and sent to the Laboratory of Protozoology and Entomology (LAPEn), for incubation in a bacteriological growth greenhouse and subsequent identification of the protozoan on a slide in wet mounting under an optical microscope in a 40X objective. Wet mounting on a slide was performed in triplicate and analyzed in its entirety. Of the 300 birds evaluated in in vitro culture for T. gallinae, 25 had inconclusive results and were submitted to PCR analysis, being negative for T. gallinae. Although no positive Passeriformes was found, the monitoring of the occurrence of this protozoan must continue, as it is known that it may easily cause a possible epidemic, leading to losses for the wild fauna that has endangered birds.