What's the difference between contagious and infectious?

Question

I was at a party the other night were a guy posed this question and stated that there is no simple answer. I then asked if there actually is a difference between the two. That too, he responded stating that there is no simple answer. So first of all, is there a difference between contagious and infectious? If so, what is the difference? Thanks.

Answer 1

A disease that is "contagious" is usually passed on from one individual to another. It is spread via touch, body fluids or from an object that person handled. Examples would be measles and chicken pox,

A disease that is "infectious" is contracted via food, water or air. It does not require direct contact since the germs enter your body via air droplets. These germs then multiply causing illness.
Examples would be respiratory illnesses and AIDs.

Btw, a contagious disease is also an infectious disease! That is why he stated that there is no simple answer. However, an infectious disease is not always contagious. So, all contagious diseases are infectious diseases but not all infectious diseases are contagious!

I wanted to find a site for you to explain it and found this:
http://en.wikipedia.org/wiki/Infectious_disease
.