Disease spread by mosquitoes (7)
I believe the answer is:
malaria
'disease spread by mosquitoes' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for malaria that I've seen before include "Mosquito-borne disease" , "Disease from bites by infected mosquitoes" , "Disease from bites by infected mosquitos" , "Fever-inducing disease" , "Disease causing fever transmitted by mosquitos" .)