Epidemiology

1. When an epidemic spreads extensively to affect people across multiple continents - or even throughout the whole world.
2. Organisms which are exposed to and harbor a disease. (The "who" of the Triangle)
6. What are diseases caused by?
7. The favorable surroundings and conditions external to the host that cause or allow the disease to be transmitted. (The "where" of the Triangle)
10. A model scientists have developed for studying health problems.
11. When more than one epidemic co-occurs and together interact to worsen the other.
12. What does the center of the Triangle represent?

1. Otherwise known as parasites (they live off other organisms).
3. When a population has a high level of the disease all the time.
4. The study of that which befalls people
5. The cause of the disease. (The "what" of the Triangle)
8. Exists when there are more cases of a particular disease than expected in a given area, or among a specific group of people, over a particular period of time.
9. Single-celled organisms capable of reproducing themselves, by themselves.