Hi all…just when I thought we had a pretty good handle on protozoan pathogens, a new survey in Shanghai reveals that there are new species being identified in wastewater and combined sewer overflows. Not only are there some such as Enterocytozoon bieneusi that aren’t monitored for in North America but there are new species of Cryptosporidium and Giardia which in some cases are not only causing disease in humans but are host specific to humans.
The authors report “…like untreated urban wastewater, combined sewer overflow is commonly contaminated with human-pathogenicCryptosporidium, G. duodenalis, and E. bieneusi 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 indicate that “Cryptosporidiumubiquitum and Cryptosporidium viatorum, two newly identified human pathogens, may be common in China…”
And, they also state “C. ubiquitum is a common parasite of small ruminants and rodents. However, it is becoming an importantCryptosporidium species in humans in industrialized nations and has only been reported in only a few human cases in developing countries. In contrast, C. viatorum is known as a human pathogen in developing countries, as human infections in the United Kingdom and Sweden have been linked to travel to India, Pakistan, Bangladesh, Kenya, Barbados, and Guatemala…In the present study, C. viatorum was detected at a frequency similar to those of C. hominis, C. parvum, [both of which are common in North America] and C. ubiquitum.”
There’s no reason to suspect that these new species would be any more difficult to remove/inactivate than those we are dealing with at the moment.
Bill
Environmental Transport of Emerging Human-Pathogenic Cryptosporidium Species and Subtypes through Combined Sewer Overflow and Wastewater
Chengchen Huang, Yue Hu, Lin Wang, Yuanfei Wang, Na Li, Yaqiong Guo, Yaoyu Feng, and Lihua Xiao
Applied and Environmental Microbiology (AEM) August 2017 83:e00682-17; Accepted manuscript posted online 9 June 2017, doi:10.1128/AEM.00682-17
http://aem.asm.org/content/83/16/e00682-17.abstract?etoc
ABSTRACT
“The environmental transport of Cryptosporidium spp. through combined sewer overflow (CSO) and the occurrence of several emerging human-pathogenic Cryptosporidium 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 Cryptosporidium species (targeting the small subunit rRNA gene) and Giardia duodenalis (targeting the triosephosphate isomerase, _-giardin, and glutamate dehydrogenase genes) and Enterocytozoon bieneusi (targeting the ribosomal internal transcribed spacer) genotypes. Human-pathogenic Cryptosporidium species were further subtyped by sequence analysis of the 60-kDa glycoprotein gene, with additional multilocus sequence typing on the emerging zoonotic pathogen Cryptosporidium ubiquitum. Cryptosporidium spp., G. duodenalis, and E. bieneusi were detected in 12 and 15, 33 and 32, and 37 and 40 CSO and wastewater samples, respectively, including 10Cryptosporidium species, 3 G. duodenalis assemblages, and 8 E. bieneusi genotypes. In addition to Cryptosporidium hominis and Cryptosporidium parvum, two new pathogens identified in industrialized nations, C. ubiquitum and Cryptosporidium viatorum, were frequently detected. The two novel C. ubiquitum subtype families identified appeared to be genetic recombinants of known subtype families. Similarly, the dominant group 1 E. bieneusi genotypes and G. duodenalis subassemblage AII are known human pathogens. The similar distribution of human-pathogenic Cryptosporidium species and E. bieneusi and G. duodenalis 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 C. ubiquitum and C. viatorum in urban wastewater suggests that these newly identified human pathogens may be endemic in China.”
