Genomic epidemiology of Campylobacter jejuni associated with asymptomatic paediatric infection in the Peruvian Amazon

Campylobacter is the leading bacterial cause of gastroenteritis worldwide and its incidence is especially high in low and middle income countries (LMIC). Disease epidemiology in LMICs differs from Europe and the USA as repeated and persistent infections lead to deficits in early childhood development. In this study, we sequenced and characterized C. jejuni (n=62) from a longitudinal cohort study of children under the age of 5 with and without diarrheal symptoms, and contextualized them within a global C. jejuni genome collection. Epidemiological differences in disease presentation were reflected in the genomes, specifically by the absence of some of the most common global disease-causing lineages. As in many other countries, poultry-associated strains were a major source of human infection but almost half of local disease cases (15 of 31) were attributable to genotypes that are rare outside of Peru. Asymptomatic infection was not limited to a single (or few) human adapted lineages but resulted from phylogenetically divergent strains suggesting an important role for host factors in the cryptic epidemiology of campylobacteriosis in LMICs.