*4.3. DNA Extraction*

Based on a previous published work [22], we chose an extraction protocol offering highly satisfying performances in *C. parvum* DNA extraction from stool matrix. Accordingly, the observed PCR performances were exclusively due to amplification methods since extraction was standardized. Consequently, DNA extraction was performed using a QI-Aamp PowerFecal DNA kit (Qiagen, Courtaboeuf, France) according to the manufacturer's instructions. Briefly, it is a manual extraction kit combining thermal, mechanical, and chemical lysis. The starting volume for DNA extraction was 250 μL of sample. Obtained DNA extracts (100 μL) were stored at −20 ◦C until use. In addition, to control DNA extraction, we used Diacontrol DNA® for each sample according to the manufacturer's instructions. Ten microliters of viral DNA control was inoculated in each sample before extraction. Control DNA was subsequently detected using ready-to-use ProbePrimer mix (DICD-CY-L100) with the following PCR protocol: 50 ◦C for 2 min; 95 ◦C for 10 min; 95 ◦C for 15 s and 60 ◦C for 60 s, repeated 45 times.
