Observation of a cohort of preschool children in Dhaka, Bangladesh, is beginning to reveal
the contributions of environment, host, and parasite to amebiasis. Reviewed here are the
associations and interactions of malnutrition, IgA and interferon-γ, human leukocyte antigen
alleles, and parasite genotypes to the outcome of infection. Future efforts aimed at
understanding the mechanisms of these effects are described.