Multilocus genotyping of potentially zoonotic Giardia duodenalis in pet chinchillas (Chinchilla lanigera) in China.

Giardia duodenalis is a common protozoan that colonizes and reproduces in the small intestine, causing giardiasis. This parasite infects a wide range of vertebrate hosts, including humans, domestic animals and wildlife. It has been suggested that chinchillas (Chinchilla lanigera) kept as domestic pets are potential reservoirs for the zoonotic transmission of G. duodenalis. In this study, 140 chinchilla samples from four cities in China were examined to determine the prevalence of G. duodenalis. Thirty-eight (27.1%) chinchillas were found to be positive for G. duodenalis. The prevalence of infection was analyzed in relation to collection site, age and sex. Molecular characterization was also carried out on the 38 chinchilla samples to determine common genotypes. G. duodenalis assemblages A and B were identified in the chinchilla samples by analysis of the small subunit ribosomal RNA (ssur RNA) gene. Genotyping at the subtype level using multiple genes (glutamate dehydrogenase (gdh), triose phosphate isomerase (tpi) and β-giardin (bg) genes) determined that the majority of assemblage A isolate sequences were identical to subtype AI. Assemblage B isolates showed variability among the nucleotide sequences belonging to subtype BIV. This is the first report of G. duodenalis in chinchillas from China. As subtype AI and BIV are associated with human infection, G. duodenalis in chinchillas should be regarded as zoonotic.