Here’s a startling image for this wintry Sunday morning. You may have seen it already.

Picture a man in a tacky, grey, “rat suit” - ears, fur, tail, the whole deal. The rat-suited man is writhing on a public sidewalk, pretending he is gasping for breath. Next to this “rat-man” is a hand-lettered placard declaring, “Cyanide is in cigarette smoke - the same as it is in rat poison.”

This image is currently a public service announcement on PBS stations.

But here’s the real kicker. The “tag line” that underscores this yucky image is this: “Knowledge is contagious . . . Infect!”

February is not a pleasant time to talk positively about the benefits of “infections.” I’ll bet if you look to your right, then look to your left, one of you pew-mates has some kind of communicable wheezing thing: a …