Sounds like sailors who are sick with scurvy trying to ‘infect’ their shipmates by breathing at them. Doesn’t work there either, because scurvy is a nutrient-deficiency ill - a terrain problem rather than a transmissible germ problem. And yet - as Tom Cowan likes to point out - scurvy could sweep through a ship’s crew just as if it were an infectious disease; a ‘pandemic’, even.
PS: Sorry C. I think we posted at the same moment! 