Campylobacter Immunity and Quantitative Excretion Rates in Thai Children

Campylobaeter species were isolated from 61 (15%) of 416 Thai children <5 years old with diarrhea. Although the baseline levels of Campylobaeter-specific antibody increased with age, 80.3% of Campylobaeter-infected children seroconverted compared with 12.9% of 45 Shigellainfected patients used as controls. The response to acute infection was greatest in the 6- to 12-month-old group. Nonseroconverters had higher initial IgG levels than did seroconverters (P =.001). Quantitative cultures showed a range of 1–8 loglo Campylobaeter cfu/g of stool (median, 6.0 log₁₀), and the seroconversion rate was highest in those with the highest Campylobaeter excretion. Fecal Campylobaeter excretion was inversely related to age (x²for trend, P =.03). These studies indicate that endemic Campylobaeter exposure frequently induces seroconversion in young children, whether Campylobaeter is isolated as a single pathogen or one of multiple pathogens, and that fecal excretion ofthe organism is inversely related to the age-related immune response to infection.