The purpose of this study is determine the ability of bedide ultrasound performed in the Emergency Department and Outpatient Department can predict the severity of disease during a Dengue Fever outbreak in children, in Siem Reap, Cambodia. Our hypothesis is that the presence of gallbladder wall thickening and/or pleural effusions in children correlates with progression to Dengue hemorrhagic fever and Dengue shock. In addition, we hypothesize that sonographic imaging of pediatric patients presenting to the emergency department with a fever during a Dengue fever outbreak will change management and disposition.