This lab demonstrates the power that molecular techniques bring to managing infectious disease outbreaks. In this case study, students act as healthcare providers, diagnosing four patients who have arrived at their clinics complaining of flu-like symptoms. Students will use gel electrophoresis to discern whether their patients are suffering from seasonal flu or a new and dangerous emerging virus. This exercise reinforces how molecular tools allow healthcare providers to diagnose hard-to-distinguish infections. An optional extension offers an introduction to DNA sequence analysis and its applications in epidemiology for more advanced students.