Disorder returns in Angola, I mean Algeria (7)
I believe the answer is:
anaemia
'disorder' is the definition.
(anaemia is a kind of disease)
'returns in angola i mean algeria' is the wordplay.
'returns' says the letters should be written in reverse.
'in' indicates the answer is hidden within the clue.
'aimeana' can be found hidden inside 'angola i mean algeria'.
'aimeana' written backwards gives 'ANAEMIA'.
(Other definitions for anaemia that I've seen before include "Red blood cell deficiency" , "Blood deficiency condition" , "Llama relative, its wool" , "complaint of blood" , "Bloodlessness" .)