I know how disease works, basically. An infected sim will express symptoms like coughing, vomiting or motive drops. Everytime that happens, they generate "disease tiles" in their vicinity. These tiles remain for some time and other sims that step on them catch the disease. So far, so good.
Now my question is:
Does this "sheding" of disease tiles also happen on community lots and while the infected sim is over as a visitor at another played household?
Or put differently, can sims catch a disease by meeting an infected on a community lot and/or by inviting a disease carrier to their home?
I think the answer is yes in both cases, but I'm not entirely sure. (The most recent illness I remember is a teen catching food poisoning from gone bad sandwiches while I had him over as a visitor. But now I have a Mystery Disease outbreak - my first ever since launch - and would like to know the nitty-gritty details of contagion exactly).