The occurrence of human intestinal parasites in Finland.

A survey of the occurrence of intestinal parasites covered 243 inmates of institution for the mentally retarded, 537 hospital patients from 4 areas, 100 military servicemen, and 65 prisoners. Two faecal samples from each patient were examined by the formalin-ether concentration technique. Among the mentally retarded the prevalence of intestinal parasites was high, 41.3% among children and 51.5% among adults. The commonest parasite was Entamoeba coli. In Helsinki, the prevalence among children in hospital was only 7%, but among adult out patients, 18.9%. Among hospital patients in other areas, military servicemen, and prisoners in Helsinki the prevalence of intestinal parasites was low. The high prevalence of this protozoon, 14.8% among adult out-patients in Helsinki, probably reflects the increase in tourism. Four cases of Trichuris infection were detected among the mentally retarded.