Rife in the area when one's out of worming medicine (7)
I believe the answer is:
endemic
'rife' is the definition.
Both the definition and answer are adjectives. Perhaps they are linked in a way I don't understand?
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for endemic that I've seen before include "Commonly found in particular place - may be disease" , "(Of a disease) prevalent in a group or area" , "Confined to (disease)" , "Commonly found in a particular country or people" , "Peculiar to local area" .)