Evaluation of the protection of aquifers against pollution risks in karstic areas (PAPRIKA) method for predicting Cryptosporidium contamination.

Cryptosporidium spp. are protozoan parasites worldwide distributed, frequently responsible for gastrointestinal outbreaks from waterborne and foodborne origins. Overall European increase cryptosporidiosis incidence have recently been reported. Aim was to evaluate a specific intrinsic vulnerability mapping method for karst aquifers (PaPRIKa method) for application to Cryptosporidium contamination. Risk zones were mapped using the PaPRIKa vulnerability method enabling identification of sampling sites. From January to July 2021, eight sampling sites were investigated monthly. Cryptosporidium and bacterial contamination were evaluated using standard methods and confronted to water conductivity, turbidity, temperature and precipitation data to investigate potential correlation. Until 87% of sampling sites preselected using the PaPRIKa method were contaminated by Cryptosporidium suggesting the relevance of the method for identifying the most vulnerable sites. Oocysts were infectious in 81% of cases.Water temperature and precipitations influenced Cryptosporidium contamination. In the context of global changes where it is expected increase of waterborne disease, efficient tools to predict Cryptosporidium water resources contamination are mandatory. We suggest use of predictive tool for identification of vulnerable sites to monitor integrating nature of soils, levels of precipitations, soil saturation, land cover, urban waste and rearing areas.