What's the Difference Between Infectious and Contagious? What's
the difference between infectious and contagious? Infectious
diseases are caused by microscopic germs (such as bacteria or
viruses) that get into the body and cause problems. Some — but
not all — infectious diseases spread directly from one person to
another. Infectious diseases that spread from person to person
are said to be contagious. Some infections spread to people from
an animal or insect, but are not contagious from another human.
Lyme disease is an example: You can't catch it from someone
you're hanging out with or pass in the street. It comes from the
bite of an infected tick. Contagious diseases (such as the flu,
colds, or strep throat) spread from person to person in several
ways. One way is through direct physical contact, like touching
or kissing a person who has the infection. Another way is when
an infectious microbe travels through the air after someone
nearby sneezes or coughs. Sometimes people get contagious
diseases by touchin