Field Studies of Human Immunity to Amebiasis in Bangladesh

Amebiasis is a common cause of diarrhea and is associated with malnutrition in grade-school aged children in an urban slum of Dhaka, Bangladesh. Field Studies of Human Immunity to Amebiasis in Bangladesh was designed to determine the contribution of amebiasis to illness in the first 2 years of life when most deaths due to diarrhea occur, and understand the immunologic and genetic factors that protect children from amebiasis. The hypothesis underlying the study is that susceptibility to amebiasis is determined by host innate and acquired immune responses that vary between individuals in part due to: human genetic polymorphisms; environmental influences including malnutrition and concurrent geohelminth infection; and virulence differences among Entamoeba histolytica genotypes. Specific aims proposed in the design of the study were to: a) Measure the incidence of amebiasis and correlate it with human and parasite genetic polymorphisms, immune responses, and environmental factors such as geohelminth infection and malnutrition; b) Test the hypothesis that protective immunity is mediated both by innate immune responses initiated via TLR stimulation as well as by mucosal IgA against the Gal/GalNAc lectin and systemic IFN-γ; c) Test for the association of common genetic polymorphisms in host innate and acquired immune genes with incidence of amebiasis. 629 newborn babies were enrolled and followed regularly through bi-weekly surveillance for diarrheal episodes, anthropometry at 3-month interval until 60 months of age. The infants that were consented for GWAS analysis were genotyped in 3 separate batches at different times, on 3 different arrays. Quality control was performed on the 3 separate data sets and then jointly after merging. Genetic data available on 447 infants together with their phenotype data is made available in this submission.]]>
Inclusion Criteria: being a member of the original cohort, or being born in Mirpur, Dhaka, Bangladesh between January 1, 2008 through July 1, 2009 Exclusion Criteria:Children not enrolled at the Mirpur field site, or who are not born into the study area during the first 18 months of the study.Children older than 1 week will be ineligible to enroll.Additional reasons for exclusion include families who plan to emigrate from the study area, or newborns with jaundice or severe congenital anomalies (such as paralysis), or refusal to provide blood samples for immune or genetic analyses, or mothers who refuse to enroll their child. ]]>
Children (629) were enrolled within first week of birth between January 2008 and December 2010 and followed by twice-weekly household and quarterly clinic visits until 5 years of age.]]>