Guide caught fever a lot, running in (9)
I believe the answer is:
catalogue
'guide' is the definition.
The answer and definition can be both related to communication as well as being singular nouns.
Perhaps there's a link between them I don't understand?
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for catalogue that I've seen before include "(Ilustrated) list of items" , "List of items for sale" , "Coagulate into kind of directory" , "Brochure containing a list of goods for sale" , "Systematic list of items" .)