FIG. 2.

Results of PCR performed on DNA extracted from purified C. parvum oocysts using the Instagene matrix. The quantity of oocysts assayed is indicated above each lane. Lanes L contain the DNA ladder (rung sizes are labeled), lanes Xc contain the extraction control, and lanes ntc, ntc1, and ntc2 contain the no-template controls. (A) 18S rRNA gene (left side of the DNA ladder) and Cp11 gene (right side of the DNA ladder) PCR results with DNAs from 2,000, 348, and 16 oocysts. (B) Results of nested Cp41 gene PCR on 1,673, 206, and 80 oocysts. (The band located between the primary (1°) and secondary (2°) PCR products is an artifact of the gel electrophoresis.) (C) Results of nested Cp11 gene PCR on three replicate samples containing three oocysts.