High risk destinations include most of the developing countries of Latin America, Africa, the Middle East, and Asia. Intermediate risk destinations include most of the Southern European countries and a few Caribbean islands. Low risk destinations include Canada, Northern Europe, Australia, New Zealand, the United States and a number of the Caribbean islands. TD is slightly more common in young adults than in older people. The reasons for this difference are unclear, but may include a lack of acquired immunity, more adventurous travel styles and different eating habits.
Attack rate are similar in men and women.
The onset of TD is usually within the first week, but may occur at any time during the visit, and even after returning home. TD is acquired through ingestion of fecally contaminated food and or water. Both cooked land uncooked foods may implicated if improperly handled. Especially risky foods include raw meat, raw seafood, and raw fruits and vegetables. Travelers from industrialized countries to developing countries frequently develop a rapid, dramatic change in the type of organisms in their gastrointestinal tract.