What is the difference between the Miasma theory and the Contagion theory of epidemic disease?no

The difference between these two theories has to do with
their ideas about how the diseases are contracted -- how people come to be sick with the
disease.

The miasma theory of disease held that diseases
are caused by "bad" air.  If people are exposed to bad air, they breathe it in and
become sick.  In this theory, diseases happen because of the air and not for any other
reason.

In the contagion theory, the diseases are actually
passed from person to person.  This does not really tell us anything (not necessarily,
at least) about the ultimate cause of the disease, but it does tell us that once Person
A has the disease, he can spread it to Person B and C and beyond.  B and C will not have
to go and breathe the "bad" air.