Environmental Transmission of Shigella and Campylobacter Among Infants in Tanzania: A Culture-Independent Molecular Approach Restricted; Files Only

Barrero Castedo, Fabiana (Spring 2025)

Permanent URL: https://etd.library.emory.edu/concern/etds/df65v917z?locale=en++PublishedPublished
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Abstract

Background: Diarrheal disease bears a significant burden globally, especially among young children in low-resource settings. Enteric pathogens such as Shigella and Campylobacter are two common causative agents of this burden.

Methods: In Tanzania, 100 households were followed in a longitudinal cohort study for 12 months. Child stool samples and environmental samples (flies, food, milk, soil, and water) were collected at home visits and tested by qPCR to identify Shigella or Campylobacter species. Poisson regression was used to determine the association of positivity in environmental samples with child infections.

Results: A total of 1205 observations were analyzed. Univariate analysis showed positivity of C. troglodytis among flies (RR: 2.14, 95% CI: 1.05 – 4.35), food (RR: 2.76, 95% CI: 1.64 – 4.65), milk (RR: 5.0, 95% CI: 3.21 – 7.79), and soil (RR: 2.09, 95% CI: 1.25 – 3.48) was associated with an increased risk of child infections. Positivity of C. infans among flies (RR: 1.98, 95% CI: 1.12 – 3.51), food (RR: 2.78, 95% CI: 1.83 – 4.24), milk (RR: 6.58, 95% CI: 1.31 – 4.24), soil (RR: 3.86, 95% CI: 2.27 – 6.57), and water (RR: 1.95, 95% CI: 1.12 – 3.38) was also associated with an increased risk. Positivity of Shigella among flies (RR: 5.51, 95% CI: 1.63 – 18.59), food (RR: 16.5, 95% CI: 7.54 – 36.11), and soil (RR: 7.75, 95% CI: 3.10 – 19.39) was also associated with an increased risk. After adjusting for other environmental sample types, food (RR: 4.05, 95% CI: 1.76 – 9.33) and soil sample (RR: 10.18, 95% CI: 1.97 – 52.59) positivity was associated with increased risk of Shigella infection.

Conclusion: Among the pathogens tested, child infections with C. troglodytis, C. infans, and Shigella were more likely if detected in 3 or more sample types. Flies, food, and soil samples are potential environmental transmission pathways that have an increased risk of child positivity among several pathogens.

Keywords: Shigella, Campylobacter, Environmental Transmission, Diarrhea, Tanzania, Infants

Table of Contents

Introduction.............................................................................................................. 1

Methods..................................................................................................................... 5

Results....................................................................................................................... 9

Discussion................................................................................................................ 13

References............................................................................................................... 16

Tables and Figures................................................................................................. 20

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