Molecular detection of Cryptosporidium and Giardia duodenalis in canine faecal samples in the Qinghai Tibetan Plateau area, China

Dogs act as natural reservoirs of a large number of zoonotic pathogens, including the intestinal Cryptosporidium spp. and Giardia duodenalis, the most relevant protozoan species causing gastrointestinal diseases worldwide. An epidemiological study aiming to assess the prevalence and molecular diversity of Cryptosporidium and G. duodenalis was conducted in the Qinghai Tibetan Plateau area (QTPA), Northwest China. A total of 217 dog faecal samples were collected from sheep farms, dog farms and pet hospitals. The species/genotypes of Cryptosporidium and G. duodenalis isolated from dogs were identified by the PCR-based method targeting the partial 18S ribosomal RNA gene for Cryptosporidium and β-giardin gene for G. duodenalis. The results of Cryptosporidium spp. and G. duodenalis infections in dogs showed an overall prevalence of 2.8% (6/217) and 6.9% (15/217), respectively. No Cryptosporidium and G. duodenalis co-infections were observed. The PCR-sequence results confirmed detection of C. parvum (n=3), C. canis (n=2), C. andersoni (n=1) and G. duodenalis assemblages B (n=9), C (n=3) and D (n=3) in dogs from the QTPA. The results of the present study demonstrated that dogs in the QTPA are commonly exposed to Cryptosporidium spp. and G. duodenalis. This may indicate that dogs are potential sources of infection of Cryptosporidium spp. and G. duodenalis transmitting to humans and animals.