I had 3 illness events in a row thanks to Randy, and all 3 of them only targeted this guy.
Edit: I really don't like how Imgur has to force in it's overlay from a direct link. Time to find a new image host methinks
Edit 2: Turns out they have the 'Sickly' Trait, not sure if it's vanilla or from a trait mod I added, but they get extra sickness events, so I'm going to install a bunch of medical ribs in them and hope for the best.