Endemic Cryptosporidium infection and drinking water source: a systematic review and meta-analyses

Cryptosporidium is a well-known cause of diarrhoea in humans. Little is known about risk factors associated with endemic cryptosporidiosis, which constitutes the majority of cases. We carried out meta-analyses to verify if drinking water is also associated with endemic infection and to assess the magnitude of the associations. The global meta-analysis suggests that there is an increased risk of Cryptosporidium infection among unsafe water users (OR 1.40 [1.15, 1.72]). Studies were stratified, according to the exposure to different sources of safe drinking water, due to the heterogeneity presented. The consumption of non-well and unboiled water was associated with an increased chance of endemic cryptosporidiosis, though only the latter was significant (OR 1.45 [0.95, 2.20]; OR 1.61 [1.09, 2.38]). Drinking non-bottled water did not present a risk factor associated with endemic cryptosporidiosis (OR 0.87 [0.72, 1.05]). These meta-analyses present results that could be useful to clarify the epidemiology of Cryptosporidium. We recommend that other risk factors could also be studied by this approach.