In prison camp almost come down with right kind of fever (9)
I believe the answer is:
glandular
'kind of fever' is the definition.
(I've seen this before)
'in prison camp almost come down with right' is the wordplay.
'in' is an insertion indicator.
'prison camp' becomes 'gulag' (gulag is a kind of prison camp).
'almost' means to remove the last letter (most of the word but not all of it).
'come down' becomes 'land' (I've seen this before).
'with right' becomes 'r' (common abbreviation. I am not sure about the 'with' bit.).
'gulag' with its last letter taken off is 'gula'.
'gula' placed around 'land' is 'glandula'.
'glandula'+'r'='GLANDULAR'
(Other definitions for glandular that I've seen before include "Type of fever" , "Sort of fever" , "regarding body parts" , "Kind of fever" .)