History o' Disease

2. An epidemic that has spread across several countries and continents
3. The case of the London water pump
5. The rapid spread of a disease to a large number of people above what is normally expected and within a short period of time
13. A respiratory disease
14. Connected to the history of inoculation
15. The same as an epidemic but occurring over a more limited geographic area
17. Organization that studies disease
19. An infectious agent made of DNA or RNA that can only grow and multiply by using the machinery of other cells
20. Contributed to germ theory by understanding microbes
21. Blood defense
22. A person that is not showing any signs of having a disease despite being infected

1. Smallpox inoculator
2. Infantile paralysis
4. When enough people in a population are immune to a disease
6. the study of the distribution, causes, and risk factors of health-related states and events in specified populations
7. A factor, such as a microorganism, that is essential for the occurrence of a disease.
8. A biological preparation that is usually made of an inactivated or weakened version of a virus or bacteria
9. The proportion of persons with clinical disease, who after becoming infected, become severely ill or die
10. Refers to someone who shows no clinical signs of infection after exposure to a pathogen
11. A disease caused by an infectious agent that can pass between humans and other animals
12. Death. Europe, 1347-1351
16. United States, 1918
18. Smallpox relative