Dengue virus infections in a cohort of schoolchildren from Maracay, Venezuela: a 2-year prospective study.

In 2001, we began a prospective longitudinal study in a cohort of schoolchildren 5-13 years of age residing in Maracay, Venezuela, to determine the cumulative incidence of dengue virus (DENV) infections by virus serotype. This report presents serological data from 710 schoolchildren who were tested during the first 2 years of the study. Serological evaluations were conducted by plaque reduction neutralization test (PRNT). At study initiation, 51% of children had PRNT antibody titers against one (30.1% = 13.4% DENV-1, 14.2% DENV-2, 0.6% DENV-3, and 2% DENV-4) or multiple DENV serotypes (20.9%). By the end of the first year, 89 of 348 (25.6%) PRNT-negative children seroconverted, and 94 of 362 (26%) who were PRNT-positive in their baseline sera tested positive for additional serotypes, for an overall cumulative incidence of DENV infections of 25.8%. By serotype, the percentages found were 1.4% DENV-1, 1.4% DENV-2, 19% DENV-3, and 1.2% DENV-4. In the second year, 37 of 259 (14.3%) PRNT-negative children seroconverted, and 83 of 451 (18.4%) who had monotypic and multitypic PRNT patterns in their baseline sera exhibited additional serotype seroconversions, for an overall cumulative incidence of DENV infections of 16.9%. By serotype, the percentages found were 0.8% DENV-1, 1.5% DENV-2, 8.5% DENV-3, and 2.3% DENV-4. Overall, these results suggest a high cumulative incidence of DENV infections among 5-13-year-old school children in Maracay, Venezuela.