Molecular Detection and Characterization of Giardia duodenalis in Farmed Pigs in Three Provinces of Southern China

Giardia duodenalis is a flagellated zoonotic parasite that can infect various animals and humans, causing economic losses in husbandry and detriments to public health. Although it has been reported in pigs worldwide, there are few reports on the prevalence and assemblages of G. duodenalis infection in pigs in China. In this study, the 396 pig fecal samples were randomly collected from seven farms in Zhejiang, Guangdong and Yunnan provinces in southern China, and were examined by means of the nested PCR amplification of β-giardin (bg), glutamate dehydrogenase (gdh), and triose phosphate isomerase (tpi) for the detection of G. duodenalis. Overall, 21 fecal samples were positive for G. duodenalis, with a prevalence of 5.3%. Three risk factors are associated with G. duodenalis infection, namely, region, age and gender. Moreover, 13, six and two samples were successfully amplified at the bg, gdh and tpi gene loci, respectively. Three assemblages of G. duodenalis were identified, including assemblage E (n = 17), assemblage A (n = 3) and assemblage B (n = 1). Assemblage E was the dominating genotype and was distributed in three provinces. These assemblages of G. duodenalis have also been found in human beings, non-human primates, sheep, goats and cattle, which further reveals that farmed pigs pose a potential threat to public health.