With respect to germs the immune system will do its job, but if you've ever watched an Amazonian indigenous person, you've probably noticed their swollen belly and that has to do, not with germs, but with parasites. And that's something that the immune system doesn't seem to be very effective at dealing with. So the next time you drop food on the floor, forget about it.

All these professionals and the host has to look like a transient. Good grief have some respect.