Worker has lime treatment for disease (7)
I believe the answer is:
ailment
'disease' is the definition.
(I've seen this before)
'worker has lime treatment' is the wordplay.
'worker' becomes 'ant' (worker is a type of ant).
'has' is an insertion indicator.
'treatment' indicates an anagram.
'lime' is an anagram of 'ilme'.
'ant' enclosing 'ilme' is 'AILMENT'.
'for' is the link.
(Other definitions for ailment that I've seen before include "infirmity" , "problem" , "Slight but persistent illness" , "Physical disorder" , "Complaint, affliction" .)