C. canis, C. felis, C. meleagridis, and C. muris can also cause disease in humans. Cryptosporidium is capable of completing its life cycle within a single host, resulting in microbial cyst stages that are excreted in feces and are capable of transmission to a new host via the fecal-oral route. Other vectors of disease transmission also exist.The pattern of Cryptosporidium life cycle fits well with that of other intestinal homogeneous coccidian genera of the suborder Eimeriina: macro- and microgamonts develop independently; a microgamont gives rise to numerous male gametes; and oocysts serving for parasites spreading in the environment. Electron microscopic studies made from the 1970s have shown the intracellular, although extracytoplasmic localization of Cryptosporidium species.These species possess a number of unusual features:
an endogenous phase of development in microvilli of epithelial surfaces
two morphofunctional types of oocysts
the smallest number of sporozoites per oocyst
a multi-membraneous "feeder" organelleDNA studies suggest a relationship with the gregarines rather than the coccidia. The taxonomic position of this group has not yet been finally agreed upon. The genome of Cryptosporidium parvum was sequenced in 2004 and was found to be unusual amongst Eukaryotes in that the mitochondria seem not to contain DNA. A closely related species, C. hominis, also has its genome sequence available. CryptoDB.org is a NIH-funded database that provides access to the Cryptosporidium genomics data sets. Transfer
Infection is through contaminated material such as earth, water, uncooked or cross-contaminated food that has been in contact with the feces of an infected individual or animal.
By early September 2005, over 3,800 people reported symptoms of a Cryptosporidium infection. The "Sprayground" was ordered closed for the season on 15 August. In October 2005, the Gwynedd and Anglesey areas of North Wales, the United Kingdom, suffered an outbreak of cryptosporidiosis. The outbreak may have been linked to the drinking water supply from Llyn Cwellyn, but this is not yet confirmed. As a result, 231 people fell ill and the company Welsh Water (Dwr Cymru) advised 61,000 people to boil their water before use. In March 2007, a suspected outbreak occurred in Galway, Ireland, after the source of water for much of the county, Lough Corrib, was suspected to be contaminated with the parasite. A large population (90,000 people), including areas of both Galway City and County, were advised to boil water for drinking, food preparation and for brushing teeth. On 21 March 2007, it was confirmed that the city and countys water supply was contaminated with the parasite. The areas water supply was finally given approval on 20 August 2007, five months after Cryptosporidium was first detected. Around 240 people are known to have contracted the disease; experts say the true figure could be up to 5,000. Hundreds of public pools in 20 Utah counties were closed to young children in 2007, as children under 5 are most likely to spread the disease, especially children wearing diapers.