Microsporidia andCyclospora: Epidemiology and Assessment of Risk from the Environment

Abstract

Two classes of parasites with an environmental stage in their lifestyle have recently emerged as significant gastrointestinal pathogens for humans. Microsporidia represent a group that contains a number of genera related to the genus Cryptosporidium. They are generally transmitted via direct human to human contact, but can survive in water and food, and recently have been found in surface water used as drinking source water. Their most common host range is in patients with clinical AIDS. Limited work to date suggests the group is susceptible to chlorine achievable CxT (concentration x time) values and is coagulated by filtration. Cyclospora cayetanensis is a species of parasite that has caused outbreaks from contaminated food. Its major risk is from the use of inadequately treated water used for irrigation. Cyclospora can infect normal and immunosuppressed hosts. Current information regarding the lifestyle, transmission, and control of both groups of parasites are discussed, with a health risk assessment analysis.

Multilocus Sequence Typing Tool forCyclospora cayetanensis

“…Similarly, 14 MLST types were detected among the 26 Chinese specimens collected from 2 neighboring cities (Kaifeng and Zhengzhou) in Henan Province ( 5 ). Fresh produce is frequently contaminated by C. cayetanensis protozoa through irrigation water ( 6 ) and thus has a higher probability of containing multiple C. cayetanensis genotypes. It might be possible to use only 2 or 3 loci that are highly polymorphic and easier to sequence in C. cayetanensis genotyping, such as CYC13 and CYC21.…”

Cyclosporiasis Outbreak in Germany Associated with the Consumption of Salad

“…Therefore, the most probable routes of contamination of one or more of the implicated vegetables are fertilization with human waste or fecally contaminated water used to irrigate crops, prepare pesticides, or freshen or clean produce at their origin (15). In addition to contamination of field crops through the water route, we considered that seasonal field workers often do not have access to appropriate sanitary facilities.…”

Removal of Pathogens, Surrogates, Indicators, and Toxins Using Riverbank Filtration

“…The protozoans of concern (or potential concern), include Cryptosporidium parvum, Giardia lamblia, Cyclospora sp., and members of the Microsporididea ("Microsporidia") class, seven genera (10 species) of which have been recovered in humans (Mota et al, 2000). Cryptosporidium parvum is the primary protozoan pathogen of concern because of its:…”