MORELIA, Mexico -- My timing was awful.
Only 36 hours in Mexico, and Montezuma already was taking revenge.
For the next day, I was to lie in my Mexican host family's bedroom staring at the ceiling and the bare light bulb, racked by traveler's diarrhea (or Montezuma's revenge, as it's called).
I'm not sure what made me ill; it could have been the water or
the milk in a cappuccino I drank at a Morelia cafe.
Whatever the cause, it was another three days before I was back to normal.
Had my visit come just two weeks later, I could have been one of the first students at the Centro Mexicano Internacional Spanish-language school to try a new anti-diarrhea medicine.
The new drug -- called Zalderide -- can stop diarrhea within an hour, says Dr. Herbert L. DuPont, who supervised its testing this summer on 180 American students at two language schools in Morelia and Guadalajara, Mexico.
Although the test data are still being analyzed, "our impression is that it's very effective. But we must be careful that we are not fooled," Dr. DuPont says.
Dr. DuPont is director of the center for infectious diseases at the University of Texas in Houston and a specialist on traveler's diarrhea. The drug was developed by a Swiss firm, Zyma S.A.
More testing of Zalderide is planned in Mexico and among Swiss tourists going to Egypt, Dr. DuPont says, "so we can be sure it's not a regional phenomenon."
After the tests and evaluation are completed, the Swiss firm plans to market the drug in Europe, but not in the United States at this time. Government approval is needed for its sale in the United States.
Traveler's diarrhea is contracted primarily by eating or drinking contaminated food or beverages. Stress, increased alcohol consumption and change in diet can make a traveler more susceptible.
It occurs in most of us when a particularly hostile version of the widely prevalent E. coli bacteria -- we all carry some -- gets into the digestive system. In defense, the body emits fluid to try to flush out the bacteria: hence the diarrhea.
"Zalderide seems to turn off those faucets," Dr. DuPont says.
If the diarrhea can be halted quickly, the body can rid itself of the bacteria in 90 percent of cases, he says. If the bacteria linger, antibiotics may be necessary.
Dr. DuPont offers these tips for travelers:
* Heat kills bacteria. If the soup or main dish isn't steaming or piping hot, ask that it be reheated.
* Cold does not kill bacteria, so avoid ice.
* Avoid drinking tap water even in hotels with filter systems. Most such filters make the water look clean but don't make it safe. Sophisticated portable water filters used by climbers and backpackers do a pretty good job of trapping bacteria.
* If a food has a high acid content -- such as many citrus fruits --
bacteria won't flourish. Fruits that can be peeled before eating generally are safe. Dr. DuPont says that while the knife a vendor uses to peel or cut the fruit may not be sterile, it's not likely to be contaminated enough to cause trouble.
* Candy and other foods with high sugar content generally are safe.
* Bacteria need moisture. Dry food, such as bread, generally is safe.
* Avoid milk, since it may not have been properly refrigerated. Coffee and tea that are hot are safe; bottled soda pop and beer are safe.
* Pepto Bismol can help prevent traveler's diarrhea; drugs such as Imodium can help in cases of mild diarrhea. Check with your own doctor.
* Be cautious on the plane on the way home: You can't be sure where -- and how -- the food and drinks were handled.