Genotypic Variation of Cryptosporidium Organisms Recovered from Persons Living in Kenya, Malawi, Vietnam and Brazil

The chief causative agents of human cryptosporidiosis are the human and bovine genotypes of the species Cryptosporidium parvum, others such as C. parvum dog genotype, Cryptosporidium felis, and Cryptosporidium meleagridis have been identified both in immunocompromised and immunocompetent populations. Some of the species and the genotypes that have oocysts of similar size are morphologically indistinguishable, and may share host ranges and sites of infection. Molecular analysis of numerous genes has shown that the genus may contain more distinct species than is currently agreed. This is important in epidemiology of cryptosporidiosis as different genetic factors may be reflected in the symptoms, virulence, and infectivity the organism. This chapter presents a study on the genotypic identification of Cryptosporidium recovered from different patient groups of people in Kenya, both HIV infected and uninfected either living in the community or in hospital at the time of sample collection. Results are compared with those of isolates from other regions including Malawi, Brazil, and Vietnam.