Also known as
Montezuma's Revenge; it can be caused
by either
bacteria or amoeba. The latter is the fiercer
and long-lived of the two.
How does the disease spread? Well, it could be in the
water, and even if you are carefully not drinking water,
you may be carelessly using ice made from infected water.
The infection travels via human feces (ugh), and when
food is infected it is because an infected person
has not washed his/her hands after doing number two.
Certainly none of this information is of any consolation
once you are doubled over, running for the bathroom,
but it might help impress the need for cleanliness
in eating establishments.