Question

unknown disease or well known disease that suddenly becomes harder to control is ?

Answer 1

an emerging disease. :)

Answer 2

an epidemic...

Answer 3

Actually, an epidemic is:
A widespread occurrence of an infectious disease in a community at a particular time: "a flu epidemic". (sorry, mphetang.)
An emerging disease is a disease that has either appeared in a specific area for the first time, or has recently evolved from another disease, making it harder to control. I got this from my AP Biology textbook. :) Hope this helped you, claire827! :)

Answer 4

oh yah thanx tafkas77...much appreciated!!

Answer 5

You're welcome!