PhD Defense by Amanda Lai

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Ph.D. Thesis Defense Announcement

Sanitation in Rural Cambodia: Examining Effects of Nutrition and Sanitation Interventions on

Child Growth, Enteric Pathogens, and Antimicrobial Resistance



Amanda Lai



Dr. Joe Brown (CEE & University of North Carolina at Chapel Hill)


Committee Members:

Dr. Kostas Konstantinidis (CEE), Dr. Karen Levy (University of Washington),

Dr. Olga Shemyakina (ECON), Dr. John E. Taylor (CEE)


Date & Time: April 21, 2021, 2 pm Eastern Time

Location: https://bluejeans.com/284892725

Sanitation infrastructure is critical to supporting the environment and is a foundation of public health. Globally, over two billion people lack access to any sanitation facility. Children in low- and middle-income countries disproportionately bear the burden of disease and death associated with inadequate sanitation. Here, we present results of an impact evaluation of the Integrated Nutrition, Hygiene and Sanitation project (NOURISH), which incorporates a two-by-two factorial cluster randomized control trial to measure the effects of sanitation and nutrition interventions – delivered independently and in combination – on child health in rural Cambodia among children under 28 months of age. We took anthropometry measurements and collected stools from enrolled children 28 months after the program was delivered. Stools (N=1512) were analyzed for gene targets representing 27 pathogenic enteric bacteria, viruses, protozoa, and soil-transmitted helminths, and 28 antimicrobial resistant genes (ARGs) using multiplex RT-qPCR. Enteric pathogen detection was high, with at least one bacterial pathogen in 87% of all samples, at least one viral pathogen in 49% of all samples, at least one protozoan pathogen in 20% of all samples, and at least one STH gene in 2% of all samples. Enteroaggregative E.coli (EAEC), enteric pathogenic E.coli (EPEC), enterovirus, Campylobacter spp., and enterotoxigenic E.coli (ETEC) were the most prevalent pathogens. ARG carriage was very high: we detected at least one ARG in 99% of all samples. We detected ARGs known to confer resistance to beta-lactam (98%), chloramphenicol (94%), quinolone (95%), macrolide (99%), sulfonamide (99%), tetracycline (98%), and colistin (27%). We found no effect of the sanitation intervention on child growth, enteric pathogen infection, and ARG carriage. There are many potential reasons the intervention had a limited effect on child health in this setting. It is possible that the intervention may not have sufficiently interrupted transmission pathways or limited fecal contamination of the living environment to the extent necessary to realize an effect. More comprehensive WASH interventions may be needed in similar settings to limit the spread of fecal contamination and to support optimal health outcomes in similar populations. 


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