FIG. 1.

Detection of C. parvum oocysts recovered by micromanipulation. A diagnostic melting peak was detected with DNA extracted from 1, 2, and 40 oocysts with the High Pure PCR template preparation kit (Roche Diagnostics). The template with 0.5 oocyst was obtained by eluting DNA from 10 oocysts with 50 μl of elution buffer and introducing 2.5 μl of eluted DNA into a PCR mixture. In addition to the diagnostic melting peak, low-temperature melting peaks were observed, particularly when DNA from a few oocysts was amplified. These peaks may originate from primers-dimers, but their origins were not investigated. The dashed line shows the melting profile of the negative control reaction. Note that peak height is not always reflective of the amplicon concentration but is a measure of the slope of fluorescence versus temperature.