A Grandparents Wisdom? - Causing sickness

My grandma doesn't like to touch my Grandpa. She's afraid that his stroke will rub off on her. She says she is just kidding but in the 10 years or so since his stroke she really hasn't changed, so I think that she really believes this.

When Willow was sick the other week my Grandma asked, do you think she might have picked something up from the cats?

At first, I dismissed this as crazy talk, but you can get illnesses from animals so she wasn't off the mark.