Abstract
The coccidian protozoan parasite Cryptosporidium is increasingly recognised as a major cause of diarrhoeal disease worldwide. However, the exact modes of transmission are often unclear. The further understanding of the taxonomy of this group of organisms will be essential to an understanding of both their identification and to ascertain their potential significance to human health when recovered from environmental samples. In human the principal infectious agent is Cryptosporidium parvum. Evidence initially from isoenzyme analysis together with PCR and DNA sequenced-based analyses have all identified at least two «types» of C. parvum, that may represent two different species. Since the host range of these two genotypes differs, the epidemiology of the disease in human may also differ, although this has, to date, been incompletely investigated.
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