This story has caused me to be fearful of disease.
Why do you fear disease after knowing about the story?
A man of my age should already know how and when to avoid getting such dangerous disease, but I feel like I haven't been doing so.
It's understandable that you consider your health important. However, you should not allow fear to run your life. If you do, you will not be able to fully live the life you desire.
I still have this fear living in my body.
While it's very important to be cautious about diseases and viruses, you shouldn't be fearful to the extent that the fear itself is the unhealthy thing that's overwhelming your body. Sometimes, your mind can make your whole body sick so it's still important to have a positive outlook.