Cryptosporidium genotypes in wildlife from a new york watershed

Abstract

To identify the animal sources for Cryptosporidium contamination, we genotyped Cryptosporidium spp. in wildlife from the watershed of the New York City drinking water supply, using a small-subunit rRNA gene-based PCR-restriction fragment length polymorphism analysis and DNA sequencing. A total of 541 specimens from 38 species of wildlife were analyzed. One hundred and eleven (20.5%) of the wildlife specimens were PCR positive. Altogether, 21 Cryptosporidium genotypes were found in wildlife samples, 11 of which were previously found in storm runoff in the watershed, and six of these 11 were from storm water genotypes of unknown animal origin. Four new genotypes were found, and the animal hosts for four storm water genotypes were expanded. With the exception of the cervine genotype, most genotypes were found in a limited number of animal species and have no major public health significance.

FIG. 1.

Intragenotypic diversity in the sequences of the SSU rRNA genes of some Cryptosporidium genotypes seen in this study. Dots denote nucleotide identity to the reference sequence from GenBank. Dashes denote sequence deletions.

FIG. 2.

Phylogenetic relationship among various Cryptosporidium genotypes in wildlife in the NYCDEP watershed and known Cryptosporidium species and genotypes, as inferred by a neighbor-joining analysis of the SSU rRNA sequences. Numbers on branches are percent bootstrapping values (>50) using 1,000 replicates.