Entry in progress—B.P.
   
Wikipedia: Traveler’s diarrhea
Traveler’s diarrhea (TD) is a stomach and intestinal infection. TD is defined as the passage of unformed stool (one or more by some definitions, three or more by others) while traveling. It may be accompanied by abdominal cramps, nausea, fever, and bloating. Occasionally bloody diarrhea may occur. Most travelers recover within four days with little or no treatment.[3] About 10% of people may have symptoms for a week.  (...)  It has colloquially been known by a number of names, including “Montezuma’s revenge” and “Delhi belly”.
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Society and culture
Montezuma’s revenge (var. Moctezuma’s revenge) is a colloquial term for traveler’s diarrhea contracted in Mexico. The name refers to Moctezuma II (1466–1520), the Tlatoani (ruler) of the Aztec civilization who was overthrown by the Spanish conquistador Hernán Cortés in the early 16th century, thereby bringing large portions of what is now Mexico and Central America under the rule of the Spanish crown.
 
(Oxford English Dictionary)
Delhi, n.
Etymology: <

Delhi, the name of the capital of India.
Used attributively in Delhi belly n. slang an upset stomach accompanied by diarrhœa such as may be suffered by visitors to India; cf. gippy tummy n. at gippy n. 1c.
1944   Newsweek 28 Feb. 76/1   Joe was off again—this time to be the first to hit the heat and filth of India and the desolation of China. He got ‘Delhi belly’ (a form of dysentery) and greeted Tommy Harmon when the flyer walked out of Jap-controlled China.
1962   E. Snow Other Side of River (1963) xlii. 314   I experienced the usual agonizing symptoms of indiscretion in the East—what the G.I.‘s called Delhi-belly.