Last of malaria through extremities of tsetse fly (6)
I believe the answer is:
aviate
'fly' is the definition.
('aviate' can be a synonym of 'fly')
'last of malaria through extremities of tsetse' is the wordplay.
'last of' indicates one should take the final letters.
'through' becomes 'via' (I've seen this before).
'extremities of' means to remove the middle letters.
'tsetse' with its centre removed is 'te'.
The last letter of 'malaria' is 'a'.
'a'+'via'+'te'='AVIATE'
(Other definitions for aviate that I've seen before include "Pilot a plane" , "Ride the Zephyr, say" , "Fly" , "Handle jumbo, maybe" .)