Emerging Schistosomiasis in Europe: A Need to Quantify the Risks

Abstract

The recent recurrent outbreaks of urogenital schistosomiasis in the south of Europe were unanticipated and caught scientists and health authorities unprepared. It is now time to learn lessons from these outbreaks and to implement concrete procedures in order to better quantify the risks and prevent future outbreaks of schistosomiasis in Europe. In this context, we propose a reflection on the factors that currently hamper our ability to quantify these risks and argue that we are incapable of predicting future outbreaks. We base our reflexion on an ecological two-step filter concept that drives host–parasite interactions, namely the encounter and the compatibility filters. Global changes promote the establishment and spread of infectious diseases worldwide. Several tropical and subtropical vector-borne diseases have recently emerged in more temperate geographical areas, demonstrating that they need further considerations. An autochthonous urogenital schistosomiasis outbreak has recently been identified in Southern Europe (Corsica, France). The causative parasitic agent is a hybrid between a human-specific and a livestock-specific schistosome species. Quantifying the emerging risk of vector-borne disease requires knowledge of the ecological characteristics of parasites and their potential vectors as well as of the interactions between protagonists in Northern latitudes. Host–parasite interactions are driven by an ecological two-step filter concept (the encounter and the compatibility filters). Global changes and hybridization may affect both filters, hence hampering our ability to quantify the risk of future emergence. Thus, we are still incapable of predicting future outbreaks, and new tools need to be developed.