Physicians in most developed countries are at a great disadvantage when confronted with geographic and tropical diseases. They may be faced with prevention for patients who are outward bound or with diagnosis and treatment on their return. The practitioners' difficulties relate to inade quate teaching in medical schools and to the infrequency with which they are confronted with these exotic diseases. It is quite surprising to realize the extent of travel by Americans to areas where the tropical diseases abound: in 1979 there were 3 million trips by U. S. residents to Central and South America...