Epidemic parotitis (5)
I believe the answer is:
mumps
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">epidemic parotitis</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for mumps that I've seen before include "Contagious viral disease" , "Childhood infection" , "Acute viral disease, often in children" , "Swollen-face disease" , "harmful disease" .)