Answer: It is gastroenteritis commonly acquired in foreign countries where fecal contamination of water and food is more common than in the United States
and other developed nations. It is also known as Montezuma's revenge, Delhi Belly, and Turkey trots.
If you are on spring break in Mexico enjoying a delicious fresh fruit salad, don't be surprised if you develop abdominal pain and watery diarrhea a day or two later. Many countries, especially developing countries, have lower water quality standards than we have here in the United States. Considering that the United States still has occasional problems with produce being irrigated with contaminated water, these countries have bigger problems. Basically, if you are going anywhere south of the United States you are at risk. Africa, the Middle East, and Asia are risky.
Most cases of travelers diarrhea are blamed on the bacteria, Enterotoxigenic E. coli (ETEC)1. These bacteria produce toxins that cause the intestines to secrete excessive fluid, thus producing watery diarrhea and abdominal cramping. There may also be fever, nausea, vomiting, chills, headache, muscle ache and bloating. The symptoms start 1-3 days after exposure and usually last 3-4 days. Traveler's diarrhea can also be caused by other bacteria, viruses (such as norovirus), and parasites. It is contagious to other people so, as always, wash your hands well after using the bathroom. Here is more great info on traveler's diarrhea.
Tips for avoiding traveler's diarrhea2
If you are extremely sick, have bloody diarrhea, severe abdominal pain, or are still having symptoms after 1 week, please see your doctor. There are all kinds of nasty, exotic organisms you could have picked up in another country that we don't have very often in the U.S.
--Annie Pryor, Ph.D.