The diversity of communicable illnesses across the globe spans a wide range of organisms including bacteria, parasites, and viruses. Learning the multifarious and complicated paths of transmission, presentation, and treatment can be quite difficult to manage for the new international healthcare worker, especially while attempting to learn about regional differences and needs in foreign healthcare. The purpose of this research is to consolidate and concisely represent the most prevalent and deleterious conditions affecting people across the globe. The top five worldwide communicable diseases creating a major health burden will be covered, as well as two diseases in each of several select regions that would be commonly seen during medical mission work. These regions were chosen as the most frequently labored-in areas for international healthcare workers and include: Latin America, South America, Africa, and Southeast Asia. The combined areas represent the countries most visited and in need of healthcare aid. The most prevalent diseases and conditions in these areas are detailed as an introductory reference for the international healthcare worker.