A cross-sectional study was performed on the residents of one in every ten households in the town of Novo Airão, in the northern meso-region of the State of Amazonas, 250 kilometers from Manaus by riverboat. A family cluster sample of 89 dwellings was studied. A stool sample was requested from each of the inhabitants for examination using the Lutz sedimentation and Baermann-Moraes-Coutinho techniques, and blood was taken by venous puncture for Trypanosoma cruzi Elisa antibody testing and immunofluorescence. From a total of 316 stool samples, 87.6% had one or more parasites: Ascaris lumbricoides (35.1%), Entamoeba histolytica (29.1%), Giardia lamblia (17.4%), and other parasites with lower prevalence rates. These results were directly correlated with lack of sanitation and clean water supply. Of the 346 sera examined, 16 (4.6%) were reactive to T. cruzi antibodies, but only three showed a correlation between this result and human contact with wild triatomines, known locally as "piassava lice".