Early clinical features of dengue infection in Puerto Rico.

Early diagnosis of dengue is challenging because the initial symptoms are often non-specific, viraemia may be below detectable levels and serological tests confirm dengue late in the course of illness. Identifying dengue early in the clinical course could be useful in reducing dengue virus transmission in a community. This study analyzed data from 145 laboratory-positive and 293 laboratory-negative dengue cases in Puerto Rico to define the early clinical features of dengue infection in children and adults and to identify the clinical features that predict a laboratory-positive dengue infection. Among children, rash and age were independently associated with laboratory-positive dengue infection. Rash in the absence of cough had a positive predictive value of 100% and a negative predictive value of 82.4% as a paediatric dengue screen. Among adults, eye pain, diarrhoea and absence of upper respiratory symptoms were independently associated with laboratory-positive dengue infection. No useful early predictors of dengue infection among adults were found. Using clinical features may promote earlier identification of a subset of paediatric dengue patients in Puerto Rico. Laboratory confirmation is still necessary for the accurate diagnosis of dengue infection.