Submitted to: Parasitology Today
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/12/2000
Publication Date: 12/1/2000
Interpretive Summary: Recent advances have been made in molecular characterization of Cryptosporidium parasites. In light of new information many field specimens that look alike microscopically can now be differentiated genetically. These genetic differences have now created distinctions that require taxonomic labels. Some genetically distinct organisms are referred to as genotypes whereas others are considered species. The present study provides new data, summarizes and compares previous biological and genetic data, and indicates the importance to specialists working with infectious diseases the rationale for establishing the many newly emerging taxa within the genus Cryptosporidium.
Technical Abstract: Of 23 named species of Cryptosporidium perhaps 8 are valid. These have been confirmed by biologic, molecular and phylogenetic studies. Of these, one species, C. parvum, appears to be zoonotic, ubiquitous and prevalent. Within this species several genotypes have been identified based on 18S rDNA , HSP-70 and other gene sequences. Some genotypes may merit elevation to species status based on host specificity and/or genetic differences. Other genotypes lack enough information to establish them as new taxa but provide enough data to clearly distinguish them as unique. The relationships among these genetically related but distinct isolates provide potentially important information for tracking sources of infection, infectivity for humans and domestic animals, susceptibility to treatment of infection, and possibly susceptibility to disinfection strategies.