| A | B |
|---|
| infectious disease | a disease caused by micro-organisms, e.g. bacteria, virus, fungi or parasites; it is passed from person to person |
| pathogen | an organism that causes disease |
| transmission | passing something on |
| contamination | the process of infecting something or someone by contact |
| barrier | something that stops something else from entering |
| mucus | a sticky liquid produced by the cells in the respiratory system to keep passages from drying out |
| cilia | tiny hairs on cells that line the airways |
| acid | a chemical compound that has a pH less than 7 |
| *contagious | able to be passed from one person to another by contact |
| *epidemic | an outbreak of a contagious disease that spreads rapidly and widely |
