PHYLOGENETIC ANALYSIS OF 18S SEQUENCE DATA AND RAPD ANALYSIS OF CRYPTOSPORIDIUM ISOLATES FROM CAPTIVE REPTILES

Authors: MORGAN, UNA - MURDOCH UNIV, AUSTRALIA; XIAO, LIHUA - CDC; Fayer, Ronald; GRACZYK, THADDEUS - JOHNS HOPKINS UNIV; LAL, ALTAF - CDC; DEPLAZES, PETER - UNIV OF ZURICH; THOMPSON, ANDREW - MURDOCH UNIV, AUSTRALIA

Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/12/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: For several species of Cryptosporidum, the taxonomy is unclear and confusing. This presents a problem in evaluating specimens found in environmental water samples. Are the parasites from mammals or reptiles? Are those from reptiles infectious for domestic animals or humans? The present study clearly demonstrates by molecular techniques that a single species is found in reptiles and that is distinct from species found in mammals.

Technical Abstract: Sequence alignment of a PCR amplified 713 bp region of the Cryptosporidium 18S rRNA gene was carried out on 15 captive reptile isolates from different geographic locations and compared to both c. parvum and C. muris isolates. RAPD analysis was also performed on a smaller amount of these samples. Both techniques identified two distinct genotypes amongst the reptilian isolates and the data generated by both techniques was significantly correlated (P<0.002), providing additional evidence to support the clonal population structure theory for Cryptosporidium. Phylogenetic analysis of both 18S sequence information and RAPD analysis grouped the main genotype identified amongst the reptile isolates (C. serpentis) closely with C. muris. The second genotype identified in two reptile isolates was a previously characterized 'mouse' genotype which grouped closely with bovine and human C. parvum isolates.