Results from stool survey and treatment of the positives in the municipality of Chã de Alegria as compiled yearly by the State Secretary of Health of Pernambuco and made available at the SISPCE [14].

Res: number of residents in 2006 according to the Locations Information System of the Unified Health System; Exa: number of examined persons; %Pos: percentage of positives for Schistosoma mansoni; %Tre: percentage of treated for S. mansoni. *: Estimates not reliable to detect 10% of prevalence with 95% of confidence and ±5 percentage points in finite populations [18].