Schistosomiasis is an important endemic disease associated with environmental change caused by major economic development projects such as the construction of hydroelectric power facilities (dams and the lakes created by them). The difficulty of predicting emerging outbreaks of schistosomiasis associated with these kinds of projects, and the existence of conditions unique to particular projects, necessitate studies in each particular locality in order that appropriate preventive measures can be implemented. The increasing number of dams being built throughout Brazil is a problematic issue because these dams not only create conditions suitable for the establishment of the vector molluscs but also lead to increased permanent human settlement and tourism. The World Health Organization, as well as the Brazilian National Health Foundation, recommend a number of actions to prevent the establishment of schistosomiasis foci, including monitoring mollusc populations. This paper focuses on our work at Serra da Mesa dam, Goiás, where qualitative and quantitative surveys of the freshwater mollusc fauna have been undertaken during the period of 1997 to 2004, aiming mainly to investigate the occurrence and distribution of species of medical importance. Twenty-eight species, belonging to nine families, were found. In addition to documenting new records in the state this paper gives details of the distribution of the two species of medical importance, Biomphalaria straminea (Dunker, 1848) and Lymnaea columella Say, 1817, as well as the invasive freshwater species Corbicula fluminea (Müller, 1774) and Melanoides tuberculatus (Müller, 1774).
Freshwater molluscs; schistosomiasis vectors; invasive species; distribution
