ChickFlows in Maputo, Mozambique: High-risk Behaviors, Management Practices, and Pathways for Childhood Exposure to Enteropathogens from Chickens Restricted; Files Only
Lamar, Frederica (Fall 2021)
Pathogens transmitted in animal feces account for 28% of diarrheal deaths in children <5 years old. Small-scale poultry production is ubiquitous and increasing in LMICs, yet the containment and management of poultry-associated fecal waste is minimal. This dissertation sought to provide data to inform potential interventions to reduce child exposures to enteropathogens carried by chickens.
We conducted mixed methods study, using a triangulation convergence model design, in Maputo, Mozambique to understand high-risk pathways for child exposures to chicken-sourced enteropathogens. The first aim employed a value chain approach to map and characterize the broiler, layer, and indigenous chicken value chains. The second aim quantified microbial hazards along each value chain to determine carriage of enteropathogens and contamination of chicken meat at key settings. We collected chicken feces (N=136) and carcass samples (N=75) to detect C. jejuni/coli, Salmonella spp., and Cryptosporidium spp. and analyzed a subset of child stool samples (N=64) from the study area for C. jejuni/coli. The third aim used a time-series approach to assess the accumulation of C. jejuni/coli, Salmonella spp., and E. coli during chicken processing at informal markets. We collected rinse water (N=70) and broiler carcass (N=60) samples. Samples were analyzed using quantitative polymerase chain reaction (qPCR) assays and the Colilert-18 method.
High-risk exposure pathways are present along each value chain. We detected C. jejuni/coli in 84(76%) fecal and 52(84%) carcass samples, and Salmonella spp. in 13(11%) fecal and 16(21%) carcass samples in Aim 2 sampling. Cryptosporidium spp. was not detected. Children(92%) are infected with C. jejuni/coli. In Aim 3 sampling, C. jejuni/coli and E. coli were detected in 100% of samples, and Salmonella spp. were detected in 42% of rinse water and 48% of carcass samples, excluding baseline. C. jejuni/coli concentrations increased as more chickens were processed.
These findings illuminate food safety issues and highlight the need for properly managed poultry feces along each value chain. Informal markets are high risk for purchasing contaminated meat, which has the potential to seed household transmission. Our results provide the framework necessary to inform and design strategies to mitigate child exposures to enteropathogens carried by chickens.
Table of Contents
Dissertation Research 7
Dissertation aims 8
Study setting 11
Study design 12
Chapter 1. ChickFlows: A value chain approach to characterizing risks of chicken-related enteropathogen exposure for children in Maputo, Mozambique 24
Chapter 2. Quantifying microbial hazards along the chicken value chain in an urban low-income country setting 57
Supplemental material 92
Chapter 3. Accumulation of microbial hazards associated with broiler chicken processing at wet markets: a time-series study in Maputo, Mozambique 95
Supplemental material 130
Strengths and limitations 143
Policy recommendations 146
Future directions 147
About this Dissertation
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