RESUMEN
Biomphalaria glabrata, an intermediate host for Schistosoma mansoni, was first reported in Haiti in 1891 at one location in the Départment du Nord and in 1977 it was reported at several sites in one additional watershed. Our study identifies two additional locations each on a different watershed plus a third possible site. A wide but discontinuous distribution of the snail on the north coast of Haiti is confirmed (no autochthonous infections with S. mansoni have been reported). While there are many possible explanations for this discontinuous distribution, a role for the competitor Thiara granifera in shaping the current distribution of B. glabrata is suggested. The incursion of B. glabrata into Haiti is not recent but at the same time is not expanding.