Molecular characterization of Blastocystis sp. in Chinese bamboo rats (Rhizomys sinensis)

Blastocystis sp., a parasitic eukaryote, widely colonizes the intestines of humans and a large number of animals, including rodents and lagomorphs. More than 30 million bamboo rats (Rhizomys sinensis) are farmed in China as a source of meat for human consumption. However, there have been no published articles on Blastocystis infection in Chinese bamboo rats prior to the present study. Herein, 480 fresh faecal samples were collected from R. sinensis on six farms located in four cities (Wugang, Chenzhou, Huaihua and Jishou) in Hunan Province, south-central China, and were examined for Blastocystis infection using polymerase chain reaction (PCR) targeting the small subunit ribosomal RNA (SSU rRNA) gene. The total prevalence of Blastocystis in R. sinensis was 4.58% (22/480), and significant differences in prevalence were detected among four age groups (<6 months, 6-12 months, 12-24 months and >24 months), with the highest prevalence (7.81%) in rats aged 6-12 months but with no positive samples in rats over 24 months. All farms, except for one in Jishou, were positive for Blastocystis infection, with the prevalence ranging from 1.80% to 7.27%. Sequence and phylogenetic analyses revealed two potentially zoonotic subtypes (namely ST4 and ST5) in these rodents, with ST4 predominant in all except one farm in Huaihua. Seven and five sequence types were identified within ST4 and ST5, respectively. This is the first report of Blastocystis infection in Chinese bamboo rats and the findings suggest the potential of R. sinensis to transmit Blastocystis to humans.