The National Center for Case Study Teaching in Science has served as the repository of many a fine case study, and this recent addition to their site takes on the world of tropical disease. Created by Cathy Santanello and Jennifer Rehg of Southern Illinois University at Edwardsville, this study is set in Costa Rica and its narrative introduction will help draw students into the exploration of this "mysterious ailment". After the introduction, the case study offers up a few background websites that deal with diseases in this region of Central America, and then moves on to ask some important initial questions. The other three parts of the study are similarly organized, and they include "Quest for a New Treatment" and "The Diagnostic Dilemma".