Prevalence and genetic characteristics of Cryptosporidium, Enterocytozoon bieneusi and Giardia duodenalis in cats and dogs in Heilongjiang province, China

- Cryptosporidium, Enterocytozoon bieneusi, and Giardia duodenalis infected cats and dogs.
- Zoonotic Cryptosporidium species and E. bieneusi genotypes were determined.
- Co-occurrence of zoonotic pathogens in pets and humans is of public health concern.

This study investigated 319 fecal specimens of cats (n = 52) and dogs (n = 267) from Heilongjiang province, China for the prevalence and genetic characteristics of Cryptosporidium, Enterocytozoon bieneusi, and Giardia duodenalis. PCR and DNA sequence analysis of the small subunit rRNA gene identified C. felis and C. parvum in one cat each (3.8%) and C. canis and C. ubiquitum in 6 dogs (2.2%). Polymorphisms in the ribosomal internal transcribed spacer and phylogenetic analysis characterized zoonotic E. bieneusi genotypes D, EbpC, NED1, and NED2 and host-adapted ones NED3, NED4, and PtEb IX in 18 dogs (6.7%) and human-pathogenic genotypes D and IV in 3 cats (5.8%). Genotyping based on the hypermutation of G. duodenalis triosephosphate isomerase gene (TPI) facilitated identification of assemblage F in a cat (1.9%) and assemblages C and E in 12 dogs (4.5%). Subtypes of G. duodenalis isolates were determined by measuring the diversity of both TPI nucleotide and amino acid sequences. C. canis, C. felis, C. parvum, E. bieneusi genotypes D, EbpC, and IV, and G. duodenalis assemblage C identified herein have been documented in human infections in China. C. canis, C. parvum, C. ubiquitum, and E. bieneusi genotypes D, EbpC, and IV carried by cats or dogs also existed in wastewater in China. The finding suggested pet animals could be reservoirs for human cryptosporidiosis, microsporidiosis, and giardiasis and potential sources of water contamination in China.