Two black-and-white still images from films

Left, Still image from Panic in the Streets, 1950; Right, Still image from The Work of the Public Health Service, 1936. The antagonist in Panic in the Streets, Blackie, is visually compared to a rat as he tries to climb around the rat guard onto a ship leaving New Orleans. The gangster is likely carrying plague-causing germs, just as a rat might carry plague-infected fleas onto a ship.

Twentieth Century Fox; U.S National Library of Medicine