Infectious diseases

4. tiny, single-celled living organisms
5. the percentage of infected people in a population
9. an infectious microbe consisting of a segment of nucleic acid
11. a disease which can be transmitted to humans from animals
13. the harm a pathogen does to its host
15. virus, bacteria,fungi,protozoa,worms
16. branch of medicine which deals with the incidence, distribution, and possible control of diseases
18. an epidemic of an infectious disease that has spread across a large region
19. apart of the adaptive immune response that is responsible for immunity in mammals

1. direct transfer of bacteria,viruses and other germs from one person to another
2. people, animals, food, wild animals, soil, water
3. mosquitos, ticks, fleas
6. preparation used to simulate the bodies protection against disease
7. a widespread occurrence of an infectious disease in a community at a particular time
8. responds in the same way to all germs and foreign substances
10. the body's ability to stay safe by protecting against harmful agents
12. a type of white blood cell called lymphocytes
14. tailors its attack to a specific antigen previously encountered
17. the number of new cases in a specific time period