Alright.
Well, the Spawned Canteens with water in them really do give you cholera.
However, it might be uncurable.
I definitely got the infection from a spawned canteen. I did not engage in any combat, take any hits or eaten anything. It was definitely a canteen. And I've popped the tetracycline pill as soon as I got the infection indicator.
And just as its duration finished: another one. And then another one. One pack of tetracycline later I am still suffering from cholera.
Hey, at least the water drain is faster & the drain indicator accurate.