Molecular evidence for trichomonads and acanthamoebae in cloacal samples of synanthropic waterfowl

Wild living birds that are infected with protozoan parasites may pose a risk of transmitting these to domestic fowl. While avian trichomonads are relatively often studied in this context, infection with acanthamoebae was only reported in a few terrestrial bird species. Taken together, the epidemiological role of wetland-associated bird species has been infrequently examined simultaneously for the presence of both groups of the above protozoan parasites. This study was initiated in the southern part of Central Europe, Hungary, to assess the role of waterfowl as carriers of trichomonads and acanthamoebae, involving 189 birds of 21 species from five avian orders sampled across three seasons (autumn, winter, spring). From these birds, cloacal swabs were collected and analyzed with molecular methods. Tetratrichomonas gallinarum (represented by three genetic variants) was detected in two synanthropic bird species, the Mallard (Anas platyrhynchos) and the Mute Swan (Cygnus olor), as well as a new Tetratrichomonas sp. in Ruffs (Calidris pugnax) and a Simplicimonas sp. in a Mallard. In addition, five Acanthamoeba spp., representing genogroups T4, T2, and T13, were demonstrated from Mute Swans and a Mallard exclusively in the autumn. Identical genotypes of trichomonads were only found in the same host species, even in multiple cases, while all five detected Acanthamoeba variants were represented by a single genotype per host, all of which occurred at the same location. These molecular data suggest that synanthropic waterfowl may harbor a broad spectrum of hind gut trichomonads and acanthamoebae, some of which may contaminate the environment and can be potentially acquired by domestic poultry and other vertebrates living nearby. Findings of the present study support that natural water surfaces and swimming may also entail infection with non-thermophilic opportunistic amoebae, and waterfowl should be added to the potential sources of such cases. This is particularly relevant to places where pastures are flooded with lake water.