The First Report of Tritrichomonas Foetus and Tetratrichomonas Buttreyi in Raccoon Dogs (Nyctereutes Procyonoides) in China

Background In recent years, the trichomonosis in raccoon dogs in China had occurred frequently. Pentatrichomonas hominis had been described in raccoon dogs in China in some previous studies. Purpose To Reveal whether raccoon dogs can be infected by other trichomonad species besides P. hominis , and clarify the prevalence and species distribution of trichomonad in raccoon dogs. Methods Herein, the 389 fecal samples were collected from farm-raised raccoon dogs in Hebei Province, all the samples were detected using the microscopic examination and several fecal samples containing trichomonad-like organisms were processed, cultured, stained, and photographed. Meanwhile, all the samples were screened by the species-specific nested PCR based on the small subunit rRNA (SSU rRNA) gene of P. hominis , Tritrichomonas foetus and Tetratrichomonas buttreyi , respectively, and all positive secondary PCR amplications obtained in this study were sequenced, aligned and analysed. Results 62 fecal samples (15.9%,62/389) were trichomonad-positive under light microscopy, and the trichomonad-like cells were clearly observed in the culture contents. The PCR results showed that 100 samples were trichomonad-positive, including 45 P. hominis -positive samples (11.6%,45/389), 32 T. foetus -positive samples (8.2%,32/389), and 33 T. buttreyi -positive samples (8.5%,33/389), respectively. Double mixed infections were observed in 10 samples. The prevalence of T. foetus and P. hominis were both significantly higher in raccoon dogs with diarrhea (13.9%, and 25.0%) than that in raccoon dogs without diarrhea (7.6%, and 9.3%) ( p