Hi all…another article on the presence of pathogens in wastewater has been published. What makes this one a bit different is they surveyed for Enterocytozoon bieneusi which is one of a group of obligate intracellular parasitic fungi known as microsporidia. Instead of producing environmentally resistant oocysts or cysts like Cryptosporidium and Giardia they produce spores in the range of 1 to 4 µm (more like oocysts in size, 3-6 µm). There are at least 15 microsporidian species that are human pathogens, however, Enterocytozoon bieneusi appears to be the only one that causes gastrointestinal symptoms. This pathogen can be carried by domestic and wild animal hosts. There is very little information on Enterocytozoon bieneusi in terms of its presence in drinking water and treatment recommendations. I could only locate one study of treatment plant efficiency. A total of 8 drinking water treatment plants in Spain were surveyed and it was found in influents but not in any treated waters. The plants all employed coagulation, flocculation, sedimentation, filtration, and chlorination (but no UV or O3) (Izquierdo et al., 2011. Detection of microsporidia in drinking water, wastewater and recreational rivers. Water Research 45:4837-43).
The authors of the study below identified ten Cryptosporidium species or genotypes, two G. duodenalis genotypes, and eleven E. bieneusi genotypes, most of which were human-pathogenic. This is not unexpected for a large city wastewater. What was interesting is the substantial presence of Enterocytozoon bieneusi which is a significant cause of diarrhea in children and AIDS patients.
Bill
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Human infective potential of Cryptosporidium spp., Giardia duodenalis and Enterocytozoon bieneusi in urban wastewater treatment plant effluents
Journal of Water & Health, Uncorrected proof
Ma, J., Y, Feng, Y. Hu, E.N. Villegas and L. Xiao
http://jwh.iwaponline.com/content/early/2016/01/04/wh.2016.192
ABSTRACT
“Cryptosporidiosis, giardiasis, and microsporidiosis are important waterborne diseases. In the standard for wastewater treatment plant (WWTP) effluents in China and other countries, fecal coliform is the only microbial indicator, raising concerns about the potential for pathogen transmission through WWPT effluent reuse. In this study, we collected 50 effluent samples (30 L/sample) from three municipal WWTPs in Shanghai, China and analyzed for Cryptosporidium spp., Giardia duodenalis and Enterocytozoon bieneusi by microscopy and/or PCR. Moreover, propidium monoazide (PMA)-PCR was used to assess the viability of oocysts/cysts. The microscopy and PCR-positive rates for Cryptosporidium spp. were 62% and 40%, respectively. The occurrence rates of G. duodenalis were 96% by microscopy and 92–100% by PCR analysis of three genetic loci. Furthermore, E. bieneusi was detected in 70% (35/50) of samples by PCR. Altogether, ten Cryptosporidium species or genotypes, two G. duodenalis genotypes, and 11 E. bieneusi genotypes were found, most of which were human-pathogenic. The chlorine dioxide disinfection employed in WWTP1 and WWTP3 failed to inactivate the residual pathogens; 93% of the samples from WWTP1 and 83% from WWTP3 did not meet the national standard on fecal coliform levels. Thus, urban WWTP effluents often contain residual waterborne human pathogens.”
