Extraction and Genotyping of Cryptosporidium parvum DNA from Fecal Smears on Glass Slides Stained Conventionally for Direct Microscope Examination

A method was developed for extracting cryptosporidial DNA from stained fecal smears on glass microscope slides. The correct genotype of Cryptosporidium parvum was amplified by PCR from 89 (85%) of 105 smears following conventional staining but not from negative controls. This technique may have applications for analysis of other infectious agents.