The microorganisms comprising the human microbiome outnumber the human's own body cells. These microorganisms live on our skin, as well as inside our bodies, including in our saliva, mammary glands, and gastrointestinal tract. The microorganism community occupying the gastrointestinal tract - the gut microbiota - is the largest. Data show that the microbial community of the gut varies across human populations and that the first years of life are a critical period for its development, with implications for the infant's immediate health and biological development, as well as long-term risk of disease. Thus, understanding the factors that influence the development of the gut microbial community during this critical period is essential to inform policies and programs aimed at improving child development and population health within the USA and globally. This longitudinal study explores the role an important, but understudied factor - pathogen exposure - plays in shaping the gut microbial community of infants and considers how culturally driven routines, shaped by family's social and economic conditions, influences pathogen exposure. This project will cross-train undergraduate and graduate students in anthropology, microbiology, public health and medicine to work as an interdisciplinary and international team.
Globally, enteric pathogens are a leading cause of infant morbidity and mortality. Even in highly-developed settings such as the USA, individuals come in contact with enteric pathogens in their environment, water and food, and through contact with domestic animals. Despite their ubiquity in the environment, research on their role in shaping succession of the infant gut microbial community remains sparse. Furthermore, while cultural norms, local ecology and socioeconomic conditions interact (i.e., developmental niche) to shape the context in which the infant and its gut microbial community develop, biocultural models have yet to be used to understand the succession process and related infant health outcomes. This study addresses both gaps by utilizing ecocultural theory as a framework to guide a longitudinal investigation of gut microbial succession among Brazilian infants (birth-2 years) living in conditions of high and low enteric pathogen exposure. Over a three-year period, researchers will (1) investigate infant care routines, the meanings caregivers attach to them and the sociocultural factors that structure them, (2) document infant exposure to and infection with enteric pathogens, (3) determine the extent to which infection with common enteric pathogens alters or delays typical gut microbial maturation and affects community stability, and (4) relate differences in gut microbial succession to child health and developmental outcomes. Belem, Brazil is an ideal site for this research. Stark economic inequality provides the context to study a cohort of infants living in the same cultural setting, but with dramatically different access to public health infrastructure and risk of enteric pathogen exposure. Additionally, the research team has a successful track record of productive research collaboration and the expertise to conduct the work. This study will help clarify the role enteric pathogens play in succession of the infant gut microbial community and will further the application of biocultural models for understanding human biological variation and health.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
