Microbiota and Health Study: a prospective cohort of respiratory and diarrheal infections and associated risk factors in Bangladeshi infants under two years

Background Early childhood respiratory and diarrheal infections are major causes of morbidity and mortality worldwide. There is a need to further assess the epidemiology through prospective and community-based studies to gain key insights that could inform preventative measures to reduce the risk of infectious disease in this vulnerable population. We aimed to analyze the burden and determinants of acute respiratory infection (ARI) and diarrhea episodes affecting infants during their first 2 years of life with state-of-the-art molecular technologies. Methods The ARI and diarrhea episodes were prospectively collected in a community-based, longitudinal cohort of infants (n=267) from birth to 2 years of life in Bangladesh. Women were recruited during the third trimester of pregnancy. Demographic, socioeconomic, and environmental information on the households was recorded. Nasopharyngeal and fecal samples were collected during regular scheduled visits from mother-infant pairs, and also from the infants during unscheduled visits for reported illnesses. New generation sequencing methods will be utilized to determine microbiota composition and function, supplemented by the state-of-the-art multiplex molecular detection technology for a wide range of bacterial and viral pathogens. Discussion This study sought to assess the epidemiology of both respiratory and gastrointestinal illnesses during the first 2 years of life in children from a peri-urban community of Dhaka, Bangladesh. Characteristics of the mothers, as well as birth characteristics of infants enrolled in the Microbiota and Health Study are presented here. We will determine any potential association between microbiota composition and the abovementioned illnesses, and also examine the influence of known and hypothesized risk factors on the occurrence of infections. Such putative factors include environmental, socioeconomic, maternal, clinical, and selected genetic factors, namely the variation of the fucosyltransferase genes ( FUT2 and FUT3 ) of mothers and infants. This study will add to current knowledge about these early childhood infectious diseases, and will provide data to generate hypotheses for the development of nutritional approaches to be used as prevention strategies. Trial registration The study was retrospectively registered at clinicaltrials.gov as NCT02361164 (February 11, 2015).