Cryptosporidium: parasite and disease

Cryptosporidium in rivers of the world: the GloWPa-Crypto model

“…6) Oocysts, the robust survival stage of Cryptosporidium, can survive in the environment for months and are resistant to disinfection (Nasser, 2016;Peng et al, 2008). 7) Cryptosporidium is zoonotic, meaning that it can infect humans and a variety of animal hosts, including important livestock species such as cattle (Robertson et al, 2014;. Environmental transmission between humans and animals is common (Squire and Ryan, 2017).…”

“…QMRA can also help inform what level of water treatment is needed to meet a health-based target, and it can aid in decision making on investments in the water system (Howard et al, 2006;World Health Organization, 2017a). Infection with enteric pathogens can occur via direct contact with contaminated faeces (Zambrano et al, 2014), but often transmission occurs via an environmental route, in which rivers play an important role (Cacciò and Widmer, 2014). In the case of waterborne transmission, the exposure depends on the concentration of the pathogen in the ingested water.…”

“…The relative importance of the different sources will differ per location, and is often not known. Cryptosporidium is a very persistent pathogen that can survive for months in the environment (Monis et al, 2014;Peng et al, 2008). Nevertheless, oocysts decay does take place in the environment; survival is influenced by a number of different factors, such as ambient temperature and solar radiation (Peng et al, 2008).…”

“…Nevertheless, oocysts decay does take place in the environment; survival is influenced by a number of different factors, such as ambient temperature and solar radiation (Peng et al, 2008). Furthermore, processes like sedimentation and resuspension from sediments can influence oocysts concentrations in rivers (Monis et al, 2014). Cryptosporidium cannot reproduce outside of a human or animal host, so growth in the environment does not take place.…”

“…Infection with Cryptosporidium can occur when contaminated water is ingested, for example during drinking, recreation or consumption of irrigated vegetables (Cacciò and Widmer, 2014;Dixon, 2016;Shirley et al, 2012). Ingestion of a dose as low as 10-30 oocysts is reported to cause infection in 20-66% of healthy adults (Chappell et al, 2006;DuPont et al, 1995).…”