Is it absolutely necessary to use "the" or "his"before the word "illness" in the following sentence to make it correct?
Last winter Victor got such a serious infection that it took him two months to recover from illness.
Is it absolutely necessary to use "the" or "his"before the word "illness" in the following sentence to make it correct?
Last winter Victor got such a serious infection that it took him two months to recover from illness.
So according to Mr. Andrew Leach and Mr. Peter Shor in the comments, both sentences are grammatically correct. However, the word illness's meaning will slightly change depending on whether the article is present or not. The lack of a determiner would mean Victor is recovering from generic illness, whileas the presence of a determiner would mean that Victor is recovering from a specific illness (the illness that both parties, the speaker and the listener, know about).
Credit to: Andrew Leach & Peter Shor who answered this in the comments. I only compiled their answers. This question has long been answered. It shouldn't have been under the "Unanswered" section for this long.
The is anaphoric. Without the the noun becomes generic.