Environmental Transport of Emerging Human-Pathogenic Cryptosporidium Species and Subtypes through Combined Sewer Overflow and Wastewater.

The environmental transport of spp. through combined sewer overflow (CSO) and the occurrence of several emerging human-pathogenic species in developing countries remain unclear. In this study, we collected 40 CSO samples and 40 raw wastewater samples from Shanghai, China, and examined them by PCR and DNA sequencing for species (targeting the small subunit rRNA gene) and (targeting the triosephosphate isomerase, β-giardin, and glutamate dehydrogenase genes) and (targeting the ribosomal internal transcribed spacer) genotypes. Human-pathogenic species were further subtyped by sequence analysis of the 60-kDa glycoprotein gene, with additional multilocus sequence typing on the emerging zoonotic pathogen spp., , and were detected in 12 and 15, 33 and 32, and 37 and 40 CSO and wastewater samples, respectively, including 10 species, 3 assemblages, and 8 genotypes. In addition to and , two new pathogens identified in industrialized nations, and , were frequently detected. The two novel subtype families identified appeared to be genetic recombinants of known subtype families. Similarly, the dominant group 1 genotypes and subassemblage AII are known human pathogens. The similar distribution of human-pathogenic species and and genotypes between wastewater and CSO samples reaffirms that storm overflow is potentially a significant contamination source of pathogens in surface water. The frequent identification of and in urban wastewater suggests that these newly identified human pathogens may be endemic in China. spp., , and are major waterborne pathogens. Their transport into surface water through combined sewer overflow, which remains largely untreated in developing countries, has not been examined. In addition, the identification of these pathogens to genotypes and subtypes in urban storm overflow and wastewater is necessary for rapid and accurate assessment of pathogen transmission in humans and transport in the environment. Data from this study suggest that, like untreated urban wastewater, combined sewer overflow is commonly contaminated with human-pathogenic , , and genotypes and subtypes, and urban storm overflow potentially plays a significant role in the contamination of drinking source water and recreational water with human pathogens. They also indicate that and , two newly identified human pathogens, may be common in China, and genetic recombination can lead to the emergence of novel subtype families.