The Case: A 70-year-old man presented with a 3-day history of abdominal cramping, nonbloody diarrhea and fever. The patient had returned 2 weeks earlier from a trip to a 5-star allinclusive resort in Punta Cana, Dominican Republic, where he had eaten food only at the resort and had drunk bottled water. He had made no day trips. In the final days of his trip, the patient had developed watery diarrhea that resolved spontaneously shortly after he returned to Canada. He had not received pretravel vaccinations, nor had he taken malaria prophylaxis. The patient's medical history included gastritis that had been treated with pantoprazole and successful catheter ablation for treatment of atrial fibrillation.On physical examination, the patient was free of symptoms of severe infection with a temperature of 39.0°C, heart rate 82 beats/min and regular, and a blood pressure of 124/77 mm Hg. He had right lower-quadrant abdominal pain without signs of peritonitis. There was no rash. The results of routine blood tests were normal. A CT scan