Authors

J Boissier¹;  ¹ University of Perpignan

Discussion

Schistosomiasis is a snail-borne parasitic disease endemic in several tropical and sub-tropical countries. However, in the summer of 2013, an unexpected outbreak of urogenital schistosomiasis occurred in Corsica, with >120 locals/tourists infected. Parasitological/malacological surveys and snail-parasite compatibility experiments were conducted together with the molecular characterisation of the schistosomes to elucidate the etiology of this outbreak. Two main infection foci were identified along the Cavu River with many Bulinus truncatus snails found in both locations. Among 3,544 snails recovered none were found naturally infected but laboratory experimental infections confirmed their compatibility with the schistosomes isolated from the patients. Molecular characterization of 73 eggs/miracidia isolated from 12 patients confirmed infection with Schistosoma haematobium, S. haematobium x S. bovis hybrids and S. bovis. Further sequence data analysis also revealed a close relationship of the Corsica schistosomes to those from Senegal, West Africa. The Cavu River's freshwater swimming pools harbour many B. truncatus snails, capable of transmitting S. haematobium-group schistosomes. The molecular data strongly corroborates that parasites were imported into Corsica by infected individuals from West Africa, specifically Senegal, with the hybridization between S. haematobium and the cattle schistosome S. bovis having a putative role in this outbreak. This finding demonstrates how easily/rapidly urogenital schistosomiasis can be introduced and spread into novel areas where Bulinus snails are endemic but also how hybridization could increase the colonization potential of schistosomes. Furthermore this highlights the potential risk of schistosomiasis outbreaks in other European areas, warranting close monitoring and surveillance of all potential transmission foci.