Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
Numerous exotic diseases await those traveling to developing countries, but some simple precautions and vaccines can minimize the risk.
The most commonly acquired disease is traveler's diarrhea that affects up to 40% of travelers. Hepatitis A, a more serious disease, affects less than 1% of travelers. Typhoid fever, malaria, yellow fever, and meningitis are even rarer. The latter diseases are potentially fatal, and the sensible traveler should take precautions against them. Some of these diseases are transmitted by biting insects, others by eating contaminated food or inhaling organisms.
The following list shows ways certain diseases are spread:
Diseases spread by contaminated food and water: traveler's diarrhea, hepatitis A, thyroid fever, polio, and cholera
Diseases spread by mosquitoes and other insects: malaria, yellow fever, and Japanese encephalitis
Traveler's diarrhea: Diarrhea is among the most frequent health problems encountered by travelers. Up to 40% of short-term travelers to developing countries and up to 70% of long-term travelers will experience at least one bout of diarrhea. Because traveler's diarrhea is caused by eating or drinking contaminated food and water, people traveling under primitive conditions are at highest risk.
The risk of diarrhea varies according to the destination, with the highest risk (30-70%) found in Asia, Africa, and Latin America. Travel to the Caribbean, the Mediterranean, Pacific islands, southern Europe, Israel, and Japan carries a lower risk of diarrhea.
Many different types of organisms cause traveler's diarrhea. Symptoms vary, but most affected travelers have four to five stools per day for three to four days. Some people have only a few hours of diarrhea. More unfortunate travelers have profuse and frequent stools. About 30% of affected travelers are confined to their rooms, and 40% have to curtail their scheduled activities. High fever, significant abdominal pain, and bloody stools are hallmarks of a more serious type of diarrhea and should cause the traveler to seek medical attention.
Select food and drink with care. In most cases, the traveler should carry along an antibiotic to take in case diarrhea develops. If diarrhea is mild, bismuth subsalicylate (Pepto-Bismol), loperamide (Imodium), or diphenoxylate hydrochloride (Lomotil) may be taken to slow things down while the antibiotic is working. These medicines should not be taken if bloody diarrhea, severe abdominal pain, or high fever is present.
It is possible to reduce the risk of diarrhea by taking antibiotics or bismuth subsalicylate daily. However, this approach has its own risks and inconveniences. It should be reserved for the rare traveler for whom even a couple hours of diarrhea would be a serious inconvenience.
Cholera: Although cholera calls up visions of medieval plagues and can be a major cause of anxiety in tourists, it is really very hard to catch. The risk of cholera has been estimated at two cases per million travelers.
Cholera is a problem in areas where significant amounts of human waste contaminate food or water. The level of contamination must be very high, because a large number of the cholera bacteria must be ingested to cause the disease. This causes the food to smell or taste so bad that few tourists are tempted to eat it. Occasionally, the foul taste is covered with spicy sauces. Raw shellfish have been a source of disease in some areas.
For the very rare tourist who gets cholera, the good news is that symptoms are usually limited to a few days of diarrhea. If careful attention is paid to drinking fluids, and in severe cases to replacement of salts and sugars, the symptoms go away and do not return. With severe disease, you may have copious watery diarrhea that may exceed 1 liter per hour.
The cholera vaccine is not very effective. Currently, vaccination is not recommended or required for international travel. In fact, it is no longer on the market in the United States.