Amoebiasis and giardiasis in Bangladesh: parasitological and serological studies.

To determine the prevalence of infections with Entamoeba histolytica and Giardia lamblia in Bangladesh, we screened stool specimens from patients with diarrhoea attending urban (N = 2,246) and a rural (N = 2,791) hospital and a group of healthy urban residents (N = 440). Sera from 200 healthy villagers were also examined for antibody to E. histolytica using the immunofluorescent antibody test. The prevalence of E. histolytica cysts or trophozoites in all groups assessed by examination of a single stool specimen ranged from 0% among infants (less than 1 year) to 34% among healthy adults 30 to 44 years old. G. lamblia was uncommon in infants and found most frequently in urban hospital patients aged five to nine (21%). 12% of one- to two-year-old children had serum antibody to E. histolytica at a titre of 1:40. By age 14 years, 80% of those tested were seropositive, and this prevalence declined thereafter with increasing age. Amoebiasis and giardiasis occur frequently in Bangladeshi populations and the morbidity and mortality associated with these infections need to be assessed.