Possible competitive displacement of planorbids by Melanoides tuberculata in Minas Gerais, Brazil

Several species of snails, including Pomacea haustrum, Marisa cornuarietis and Helisoma duryi, have been identified as probable competitors and/or pre dators of planorbid intermediate hosts of Schistosoma. During the last few years, studies carried out in the Caribbean region have shown reductions an d even disappearances of populations of Biomphalaria glabrata and B. strami nea. in breeding places where the snail Melanoides tuberculata was introduc ed. Observations made over a period of 10 years in two lakes close to Belo Horizonte, MG, showed that there were marked reductions in autochthonous po pulations of B. glabrata and B. straminea after the arrival of M. tubercula ta, both Biomphalaria species disappearing completely after eight years.