Nurse and medic treated disease (7)
I believe the answer is:
endemic
'disease' is the definition.
(I know that endemic is a type of disease)
'nurse and medic treated' is the wordplay.
'nurse' becomes 'EN' (abbreviation for enrolled nurse).
'and' says to put letters next to each other.
'treated' is an anagram indicator.
'medic' anagrammed gives 'demic'.
'en'+'demic'='ENDEMIC'
(Other definitions for endemic that I've seen before include "Belonging to a particular area" , "Commonly found in a particular country or people" , "Men dice in way commonly found in country or place" , "Local (of disease)" , "locally confined" .)