The Puerto Rico Active Dengue Surveillance (PRADS) is a research project that aims to develop an infrastructure for a hospital-based active dengue surveillance system that will serve as a model and as a platform to study the epidemiology of dengue in Puerto Rico (PR). Dengue is endemic in PR with increasing number of cases and severity of disease. It has been difficult to control. The objectives of the project include studying the age-specific incidence of symptomatic dengue from infants to adults, estimating the clinical burden of disease, describing the clinical presentation and outcomes of pediatrics and adult patients diagnosed with dengue, and determining the management practices associated with poor outcomes. The surveillance activities for the project will be located at the University of Puerto Rico School of Patients and the University Pediatric Hospital; both are referral tertiary care hospitals located at the Medical Center in San Juan, and the UPR Hospital a secondary care hospital located in Carolina. Case finding will start with acute febrile patients in all age groups from infants to adults. Patients with dengue fever will be followed through the disease. The surveillance protocol will include medical history, physical examination, and laboratory testing including dengue diagnostic tests. Electronic data collection will be done using the RedCAP system for collecting, storing, and disseminating project- specific research data.