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Risk Assessment in Wastewater Reclamation and Reuse
Published in Donald R. Rowe, Isam Mohammed Abdel-Magid, Handbook of Wastewater Reclamation and Reuse, 2020
Donald R. Rowe, Isam Mohammed Abdel-Magid
Following are the major pathogenic protozoa found in wastewater and the diseases associated with them.19–21Entamoeba histolytica: causes amoebic dysentery, liver abscess, and colonic ulcerations.Giardia lamblia: causes anorexia, diarrhea, and infections of the small intestine.Blantidium coli: causes diarrhea, colonic ulceration, and dysentery.Cryptosporidium: causes diarrhea.
Pathogen contamination of groundwater systems and health risks
Published in Critical Reviews in Environmental Science and Technology, 2023
Yiran Dong, Zhou Jiang, Yidan Hu, Yongguang Jiang, Lei Tong, Ying Yu, Jianmei Cheng, Yu He, Jianbo Shi, Yanxin Wang
Cryptosporidium parvum, Giardia lamblia, and Entamoeba histolytica are the representative protozoal pathogens for emerging waterborne diseases including cryptosporidiosis, giardiasis and amebiasis, respectively (Table S2). The control of waterborne protozoa has been challenging because most of them produce cysts, oocysts or eggs that are extremely resistant to disinfection and filtration processes (WHO, 2017a). In addition, some of the protozoa can be highly stable for up to 18 months in cold environments (e.g., groundwater) (Table S2). The life cycle for the parasitic protozoa initiates from their cysts and oocysts in wastes, water sources, and even in drinking water treated with conventional methods (Fayer, 2004). Taking Giardia as an example, ingestion of contaminated water and food can introduce their cysts and oocysts into the digestive tract of the hosts. In the small intestine, each cyst produces two trophozoites, which multiply by longitudinal binary fission. The trophozoites remain in the lumen of the proximal small bowel, where they can be free or attached to the mucosa by a ventral sucking disk. When they transmit toward the colon, encystation occurs to form a protective cyst wall around trophozoites, possibly in response to bile concentration. Both cysts and oocysts can be found in the feces. They are released into the external environment during defecation and lead to a new round of infection (Krauss and Griebler, 2011; Omarova et al., 2018).