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PHYLOGENETIC ANALYSIS OF CRYPTOSPORIDIUM PARASITES BASED ON THE SMALL SUBUNIT RIBOSOMAL RNA GENE LOCUS
Citation:
Xiao, L., L. Escalante, C. Yang, I. M. Sulaiman, A. A. Escalante, AND A. A. Lal. PHYLOGENETIC ANALYSIS OF CRYPTOSPORIDIUM PARASITES BASED ON THE SMALL SUBUNIT RIBOSOMAL RNA GENE LOCUS. Wall, J.D. (ed.), APPLIED AND ENVIRONMENTAL MICROBIOLOGY. American Society for Microbiology, Washington, DC, 65(4):1578-1583, (1999).
Description:
ABSTRACT
Biologic data support the presence of multiple species in the genus Cryptosporidium, but
a recent analysis of the available genetic data has suggested that there is insufficient evidence for species differentiation. In order to resolve the controversy in the taxonomy of this parasite, we have characterized the small subunit ribosomal RNA gene (SSU rRNA) of C. parvam, C. baileyi, C. muris and C. serpentis, and undertaken a phylogenetic analysis of the genus Cryptosporidium. Our study reveals that the genus Cryptosporidium contains phylogenetically distinct species, C. parvam, C. muris, C. baileyi, and C. serpentis, which is in agreement with the biologic characteristics and host specificity. The Cryptosporidium spp. formed two clades, with C. parvam and C. baileyi belonging to one clade and C. muris and C. serpentis forming another clade. Within C. parvum, human genotype and guinea pig isolate (known as C. wrairi) each differed from bovine genotype isolates in the nucleotide sequence at four regions. A C. muris isolate from cattle was also different from parasites isolated from a rock hyrax and a Bactrian camel. Based on the genetic information, a species and strain specific PCR-RFLP diagnostic tool has been developed. These results clarify the phylogenetic status of the genus Cryptosporidium, and have led to the development of a specific and sensitive molecular typing tool.