Thanks Marketinfo, I have heard that theory before but in my...

Thanks Marketinfo, I have heard that theory before but in my opinion it does not explain how ailments can spread.

If there are no bacteria or viruses how is it possible to get the same sickness shortly after contact with a sick person?

I was "given" chicken pox, measles, and mumps as a kid by my parents arranging for me to go and spend time close to sick relatives or friends. Each time I got the ailment a few days later.

Many plagues are spread all over the world by close contact. What causes the spread of disease if not bacteria of viruses?