Molecular characterization of Cryptosporidium and Giardia in environmental samples and faecal samples from biogas users in Bac Giang, Vietnam.

Little is known about Cryptosporidium and Giardia in biogas waste and humans in Vietnam. There is a potential risk of infections during or after using the biogas system. The detected protozoan genotypes are zoonotic pathogens, and contamination of vegetables may relay through runoff to the surface waters and soil. The objective of this study was to understand the role of the environment in the epidemiology of human infections in Bac Giang province, Vietnam, with a focus on investigating the presence of Cryptosporidium spp. genotypes and Giardia assemblages among 239 environmental samples and 94 faecal samples of biogas users. PCR and sequencing analysis were used to identify the occurrence and genotypes of Cryptosporidium and Giardia in these samples. Results showed that 13/333 (3.9 %) and 9/333 (2.7 %) samples were positive for Cryptosporidium oocyst and Giardia cysts, respectively. Characterization revealed the presence of Cryptosporidium scrofarum, C. suis, C. meleagridis, C. bailey and Giardia intestinalis assemblage A and E. C. scrofarum and Giardia assemblage E were identified for the first time in humans in Bac Giang. The current information from the above investigations will be valuable for protozoan source tracking and control interventions against Cryptosporidium and Giardia infection associated with biogas wastes in Vietnam.