Causes And Treatment Of Cryptosporidium Species Are Intestinal Protozoan Parasites With A Worldwide Distribution, Responsible For Diarrheal Disease
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Cryptosporidium species are intestinal protozoan parasites with a worldwide distribution, responsible for diarrheal disease in a large number of vertebrate hosts including humans, whose infection has long been acknowledged as it is life threatening in immunocompromised patients (Current et al., 1983). The disease has a faecal-oral cycle, occurring with the ingestion of infecting oocysts, which have environmental resistance. Separate anthroponotic and zoonotic transmission cycles have been identified (Casemore and Jackson, 1984) and infection is maintained by several routes: direct person-to-person transmission, animal-to-person contact, either directly or indirectly, and by ingestion of contaminated food and especially drinking and…show more content… parvum (Angus, 1983). However, molecular characterization has recently allowed a taxonomic review of the different species and genotypes, and its value in order to better understanding the disease’s epidemiology and transmission is fully recognized. Since then, research has found remarkable evidence of genetic heterogeneity among isolates of Cyptosporidium from different hosts (Morgan et al., 1999) with some species displaying a high level of host adaptation, whereas some others have a wider host range (Xiao et al., 2002). Nineteen species of Cryptosporidium and more than forty genotypes have currently been characterized (Fayer, 2010).
Molecular analysis of human cases worldwide have shown that over 90% of human infections are caused by C. parvum and C. hominis, although their distribution depends on geographical areas and socio-economical aspects (Xiao et al., 2008). The latter is exclusive to humans and it is prevalent in developing countries whereas C. parvum has a broader host range including livestock and wildlife, that serve as reservoirs for zoonotic infection especially in developed countries (Peng et al., 1997; Xiao, 2010). Other species detected in humans are C. meleagradis (McLauchlin et al., 2000; Morgan et al., 2000), C. felis (Raccurt, 2007), C. canis (Santin and Trout, 2008; Gatei et al., 2008) and C. ubiquitum (ex cervine genotype) (Leoni et al., 2006). In the UK it is reported that C. parvum is