DNA microarray-based detection and identification of waterborne protozoan pathogens.

A DNA microarray with 21 oligonucleotide probes was developed to detect most of the common waterborne protozoan pathogens. The DNA microarray accurately identified 3 test protozoa strains based on the small subunit (SSU) rRNA gene sequence. The detection limit was approximately 1x10(3) target genes, or 50 Cryptosporidium parvum oocysts, per assay. As a parallel study to verify the efficiency of the DNA microarray, a real-time PCR assay was also developed targeting functional genes as well as the SSU rRNA gene. The present protozoa DNA microarray, when combined with our previous bacterial DNA microarray, may serve as a comprehensive water quality monitoring tool.