Disease caught by a girl going round Los Angeles (7)
I believe the answer is:
malaria
'disease' is the definition.
(I know that malaria is a type of vector-borne disease)
'caught by a girl going round los angeles' is the wordplay.
'caught by' indicates putting letters inside (I've seen this in other clues).
'a girl' becomes 'maria'.
'going round' is a reversal indicator.
'los angeles' becomes 'LA' (abbreviation).
'la' back-to-front is 'al'.
'maria' going around 'al' is 'MALARIA'.
(Other definitions for malaria that I've seen before include "Disease carried by mosquitoes" , "Disease spread by mosquitoes" , "It's transmitted by a mosquito bite" , "Disease from a mosquito bite" , "Am a liar (anag) - fever" .)