With the media hysteria over swine flu - excuse me, 2009 H1N1 influenza - I thought I'd take a shot at clearing up some confusing terms related to health and illness. They may not make you feel any safer, but take heart - it appears that the hysteria over the disease may be more to be feared than the actual germ. At least it's not "Captain Trips":

Epidemic/pandemic
An epidemic is a sudden outbreak of illness affecting more than the usual number of people or a wider range or people than usual. A pandemic is a multi-country or worldwide epidemic.

Nauseous/nauseated
We've already heard flu this and flu that, ad nauseam, but does that make us nauseous or nauseated? "Nauseated" is that unpleasant feeling in your tum-tum; "nauseous" is something that provokes that ill-feeling. As one source put it, if you say you're nauseous, you're describing how people react to you.

Infectious/Contagious
Contagious diseases spread via bodily contact with an ill person. Infectious diseases are spread by germs through air or water or some other medium. All contagious diseases are infectious, in the sense they are caused by some foreign substance entering the body, but not all infectious diseases are contagious. In any case, wash your hands!

Virus/bacteria
A virus is a chunk of protein that contains genetic material. A virus is not considered to be a living thing. It cannot reproduce on its own; it must infect a living cell to grow. Flus and colds are caused by viruses.

Bacteria, however, are one-celled living organisms. They can multiply and reproduce themselves. They cause diseases like strep, tuberculosis and scarlet fever. Antibiotics kill bacteria, but do nothing to viruses. So taking an antibiotic to fight cold symptoms or the flu is a waste of money and effort.

Inoculate vs. vaccinate
These originally were two different processes to achieve the same goal - immunity against a disease. Inoculate at first meant introducing some kind of substance into the body to provoke an immune system reaction that would provide lasting immunity. Vaccinate meant to introduce a vaccine - a liquified preparation. Their meanings have since merged.

Prone/Supine
If you catch something, either contagious or infectious, and don't have immunity, you may wind up in bed. But prone or supine? That's mostly your choice: Prone means face down, supine means face up. Me, I just curl up in a ball and will the world to go away.