Prevalence and Molecular Characterization of Intestinal Trichomonads in Pet Dogs in East China

Abstract

The trichomonad species Tritrichomonas foetus and Pentatrichomonas hominis were recently detected in the feces of dogs with diarrhea. However, little information is available on the prevalence and pathogenicity of these parasites in the canine population. Therefore, the aim of this study was to determine the prevalence and molecular characterization of trichomonads infecting pet dogs in Anhui and Zhejiang provinces, east China. In total, 315 pet dogs, with or without diarrhea, from 7 pet hospitals were included in this epidemiological survey. Microscopy and PCR detected P. hominis in 19.7% (62/315) and 31.4% (99/315) of fecal samples, respectively. T. foetus infection was detected in 0% (0/315) of samples with microscopy and in 0.6% (2/315) with PCR. The prevalence of P. hominis was significantly higher in young dogs (≤12 months) than in adult dogs (>12 months), and was significantly higher in diarrheic dogs (50.6%) than in non-diarrheic dogs (24.3%; P<0.05). Infection with T. foetus did not correlate with any risk factors evaluated in this study. A sequence analysis of the P. hominis PCR products showed minor allelic variations between our sequences and those of P. hominis strains from other hosts in different parts of the world. Type CC1 was the most common strain in dogs in east China. The internal transcribed spacer 1 (ITS1)-5.8S rRNA gene sequences from the 2 T. foetus isolates detected in this study displayed 100% identity and were homologous to the sequences of other strains isolated from domestic cats in other countries.

Keywords: Anhui; China; Pentatrichomonas hominis; Tritrichomonas foetus; Zhejiang province; pet dog.

Fig. 1

Specific locations at which specimens were collected in this study. ▲ Study locations.

Fig. 2

Alignment of the 18S rRNA sequences of the P. hominis isolates analyzed in this study and P. hominis strains of interest. Only the nucleotides that differ from those in the reference sequence (no. AY758392) are indicated. Dots represent the consensus sequence of all the P. hominis strains used in this figure.

Fig. 3

Alignment of the ITS1-5.8S rRNA-ITS2 sequences of the T. foetus isolates analyzed in this study and T. foetus strains of interest. Only the nucleotides that differ from those in the consensus sequence used are indicated. Dots represent the consensus sequence of all the T. foetus strains used in this figure, and dashes are gaps inserted to optimize the alignment. The black-boxed residues indicate differences in the ITS2 region.