Why does the narrator say, “the disease had sharpened my senses, not destroyed, not dulled them”?

I didn't read the book or know the story  but I can imagine that if it is meant to be literal, he/she said it because having the disease made him/her more careful and weary.

Explanation:

It is kind of like what happened with this Corona. We heard about the "disease" and became more weary and careful. Also: sharpened our senses.

I think the narrator meant in a non-literal way. He/she may mean that the disease made them more aware of it and knows how to prevent it next time.

May not be 100 percent correct. Wait and see if other people agrees with me.

Explanation: