Track information on love and cause of disease (8)
I believe the answer is:
pathogen
'cause of disease' is the definition.
(I've seen this before)
'track information on love' is the wordplay.
'track' becomes 'path' ('path' can be a synonym of 'track'**).
'information' becomes 'gen' (gen is a kind of information).
'on' says to put letters next to each other.
'love' becomes 'o' (In tennis, 'love' means 'zero').
'gen' put after 'o' is 'ogen'.
'path'+'ogen'='PATHOGEN'
'and' acts as a link.
(Other definitions for pathogen that I've seen before include "Heptagon (anag.)" , "Cause of disease" , "it may make one sick" , "Disease-causing micro-organism" , "cause of illness" .)