Pathogenicity and convalescent excretion of Campylobacter in rural Egyptian children

Campylobacter infection in developing countries has not received much publi c health attention because of the observation that infections are not assoc iated with disease beyond the first 6 months of life. A cohort of 397 Egypt ian children aged less than 3 years, who were observed twice weekly during 1995-1998, experienced an incidence of 0.6 episodes of Campylobacter diarrh ea per child-year. A total of 13% of the Campylobacter diarrheal episodes w ere characterized by severe dehydration. Age-specific incidence rates (epis odes per year) were 0.9 in infants aged less than 6 months, 1.5 in those 6- 12 months, and 0.4 and 0.2 in the second and third years of life, respectiv ely. Convalescent excretion of Campylobacter after a diarrheal episode migh t be enhancing transmission and contributing to this high incidence. Observ ed risk factors for Campylobacter diarrhea were poor hygienic conditions an d the presence of animals in the house. Regardless of the child's age, a fi rst infection by Campylobacter was associated with diarrhea (odds ratio = 2 .45; 95% confidence interval: 1.61, 3.71); however, subsequent infections w ere associated with diarrhea only in children aged less than 6 months. This observation that natural infection did not confer protection during the fi rst 6 months of life poses a challenge to vaccine development.