The emergence of a novel disease in the already declining population of the white-winged snowfinch is of high concern and asks for future monitoring of host and pathogen. Trichomonosis in the white-winged snowfinch

Trichomonosis, caused by the flagellated protozoa Trichomonas gallinae, is an infectious disease of birds. While formerly columbids and their predators had been mainly known to be affected, in the year 2005 first cases of trichomonosis in passerines were reported from Great Britain. In the subsequent years seasonal outbreaks became a recurrent phenomenon. The greenfinch and the chaffinch were the most affected bird species. In the years 2008 trichomonosis in finches was first reported from Fennoscandia and subsequently a continuous spread to central Europe could be observed. In the meantime, molecular studies confirmed the clonal character of the T. gallinae strain causing epidemic outbreaks in finches all over Europe. In 2019 we documented the first outbreak of trichomonosis in a formerly unaffected bird species, namely the white-winged snowfinch. Phylogenetic analysis of the ITS1/5.8S rRNA/ITS2 region together with distribution patterns and pathology of the disease suggested that the infectious agent was the epidemic T. gallinae strain from Great Britain. The emergence of a novel disease in the already declining population of the white-winged snowfinch is of high concern and asks for future monitoring of host and pathogen.