Assessment of schistosomiasis in the semi-arid Northeast region of Brazil : the São Francisco River large-scale water transposition project

Abstract

Introduction: Risk of schistosomiasis expansion to semi-arid northeastern Brazil under the influence of the Integration Project of the São Francisco River (IPSFR) was assessed. Methods: Stool examinations of schoolchildren, epidemiological investigation, and survey of the local host snail Biomphalaria straminea were performed in five IPSFR municipalities. Results: Six of 4,770 examined schoolchildren were egg-positive for Schistosoma mansoni. Biomphalaria straminea was widespread, but not naturally infected with S. mansoni. Snails experimentally exposed to two laboratory S. mansoni strains yielded infection indices of 1-4.5%. Conclusions: There is evidence of active schistosomiasis transmission in the area; thus, intensive surveillance actions are required.