In the 20th century many diseases both old and new were found to be caused by viruses.

During the 20th century, many "old" diseases of plants were found to be caused by viruses.

Only 48 at the time, he said he felt too young to have this "old man's disease."

I appear to have an old disease to share.

So when a little old disease comes along, you don't panic.

What makes anyone think the science behind a couple decade old disease is solved in any real way?

Why are we falling to a disease eight hundred years old?

This is our old disease: we understand what's going on too late.

New means are necessary to combat this old disease.

"Or it could be a new variant of an old disease," he said.