Health Risks of Travel Range from Unusual to Mundane

You've been planning and saving for that vacation in Mexico. Or perhaps you're heading to Africa, India, China or some other exotic destination. The last thing you want is for some unforeseen health problem to mar your trip. Unfortunately, millions of American travelers fail to understand what health risks they face, and the simple steps for preventing them, says G. Richard Olds, MD, Chairman of the Department of Medicine and a Professor of Medicine at the Medical College of Wisconsin.

Dr. Olds came by his interest in international travel through the influence of his father, who was a university president and a diplomat at the United Nations. "International travel is fascinating," he says. "I wish everyone could see the world." But before they set out on such trips, he says, they need to understand the risks they face and how easy it is to avoid most of them. "The educated traveler is the safe traveler," he says.

By far the most common health risk for travelers, especially those visiting developing countries, is travelers' diarrhea, which can range from mildly annoying to prolonged, painful and debilitating. According to the US Centers for Disease Control and Prevention (CDC), high-risk destinations include the developing countries of Latin America, Africa, the Middle East and Asia. Every year, the CDC says, between 20% and 50% of international travelers - an estimated 10 million people - develop diarrhea, usually within the first week of travel. Travelers' diarrhea, however, may occur at any time while traveling, even after returning home. The primary cause is contaminated food or water, typically found in areas with poor sanitation.

"We encourage people to visit those places," Dr. Olds says. "They're fascinating and wonderful places. But too often, travelers venturing outside the country - first-time travelers especially - are unaware of the health risks awaiting them, or their travel agents minimize those risks."

Ignorance of those health risks can make a traveler miserable. "Average Americans visiting Mexico for the first time - up to 85% of them - develops travelers' diarrhea," Dr. Olds says. This unpleasant condition, sometimes informally called "turista" or "Montezuma's revenge," comes in two varieties. "The milder form is the result of changes in the normal bacteria your body is used to," and usually clears up within a day or two, he said. But then there's the severe version, which results from ingesting a bacterial toxin. "It can go on for five days, accompanied by painful cramps," he says. (A third and rarer type of diarrhea is cholera, which, if untreated, can lead to death from dehydration and debilitation.)

Food and Water Precautions
Because 90% of travelers' diarrhea stems from food- and water-borne sources, many cases can be prevented by taking adequate precautions. Watch what you eat and drink, especially, and wash your hands frequently or use antibacterial hand gels. Local tap water in much of the world - excluding Canada, most of Europe, Japan and Australia - can trigger diarrhea.

Many travelers know they should avoid salads and be selective about other fresh fruits and vegetables, eating only those that can be peeled or are cooked. Dr. Olds advises travelers to also be wary of melons bought from roadside stands, because some are injected with local water to add weight.

"Not all cooked food is safe, especially food found in buffet lines and smorgasbords," he adds. Restaurants and hotels that offer such an array might not discard food that's been sitting out for hours in the heat or at room temperature. It's not uncommon for restaurants to refrigerate such leftovers and serve it the next day, when it's already absorbed bacteria and toxins from the environment. Diners who unwittingly consume such food can develop food poisoning within hours, or even a day later.

Bottled water is usually safe, but Dr. Olds has observed cases where waiters sometimes serve water bottles already opened, concealing the fact that the seal was already broken and the bottle refilled with tap water. "If you don't break the seal yourself, consider the water unsafe," he says. In addition to bottled or boiled water, tourists can safely drink beer, wine and carbonated beverages while they're out of the country. Travelers who are careful to boil local tap water to kill bacteria or drink only bottled water can still be at risk if they brush their teeth or use ice cubes made from tap water, he says.

Treating Travelers' Diarrhea
Some travelers, aware of the diarrhea risks that lurk in exotic places, take medications like Pepto-Bismol as a preventive measure, but Dr. Olds generally discourages this. "I think it gives people a false sense of security. The best preventative is education about the risks, and making good food and beverage choices when you arrive."

He does recommend, however, that travelers carry over-the-counter Imodium (or generic equivalent) and request an antibiotic prescription before they leave. If diarrhea develops, he says, try the Imodium first. If that fails to resolve the problem, then use the antibiotic. Be sure to have the prescription filled in the United States before you leave, he says, to ensure the medication is not adulterated or diluted as it could be in some foreign countries. Also, US drug insurance would probably not be honored.

"One other caveat," he adds: "Don't assume that if you're staying at an expensive hotel or resort, the food and water are automatically safe. That's a common mistake." He notes that travelers to Cancun - a Mexican resort city developed on the Yucatan peninsula during the past three or four decades - are commonly told that, because the city is so new, its hotels and restaurants are equipped with modern water filtration systems. "But remember," Dr. Olds says, "the food is brought in from other parts of the country, so the risks are the same." This is also true of the Puerto Vallarta region on Mexico's west coast: "It has the appearance of affluence, but its sewers and sanitation are not up to American standards, and the risk of typhoid is there."

Hepatitis A
Before leaving for any destination besides Canada, Europe, Japan or Australia, Dr. Olds recommends travelers be immunized against hepatitis A, which is typically spread through contaminated food and water.

Depending on factors such as your destination, altitude and the time of year, other serious diseases - including malaria, measles and polio - might be widespread in some developing countries. Travel clinics can provide medications that prevent malaria. Although most Americans were immunized against measles and polio as children, those who have not should consider receiving those vaccinations as a precaution. That includes older adults who may have received the Salk polio vaccine 40 years ago, because their immunity today is inadequate. Visitors to some countries may also need to be vaccinated against such illnesses as yellow fever, meningitis or typhoid, Dr. Olds says.

"Know what vaccines are recommended for the countries you plan to visit," he says. "Travel agents often tell you vaccinations are not required by law, but diseases don't necessarily obey the law."

Land Travel
Some tourists prefer renting cars and exploring a new country, rather than riding a motor coach or taking public transit. Be aware that in many developing countries, and especially in the rural areas, cars lack safety features like seatbelts, Dr. Olds says. Taxis in Brazil typically don't have seatbelts, he adds.

Crime and personal safety are always a concern for travelers. However, the likelihood of danger varies widely. "Some of the most remote parts of the world are quite safe," he says.

Air Travel
Some travelers worry that the air in a closed airline cabin continually recirculates, spreading germs throughout the flight. Some even say not to open the air vent above your passenger seat. Dr. Olds says those fears are generally groundless. "While your plane is sitting at the terminal and during the flight itself, fresh air continually is brought in from outside, and stale air expelled. The only time the air keeps recirculating is the time when the plane has pulled away from the terminal and before it's airborne, when fresh air begins circulating again. The only time I'd close my vent is while the plane is taxiing - or if it's in one of those long lines for takeoff at LaGuardia."

Another unexpected source of diarrhea or food poisoning can be meals served on airlines departing from a developing country. "Travelers commonly believe that if they're flying an American airline back home, the food and water must be safe. Not so," Dr. Olds says, noting that a researcher has found that food served on airlines is the most dangerous, because otherwise-careful travelers trust the food and iced drinks served aboard the flights that originate in the developing country. They can develop travelers' diarrhea after they get home.

Cruises 'Generally Safe'
Despite occasional bad publicity about disease outbreaks, cruises are generally safe, says Dr. Olds, with the possible exception of ships originating from developing countries. The most likely illnesses aboard ships are Norwalk-type viruses that can cause problems like nausea, vomiting, diarrhea and some stomach cramping. Some passengers additionally suffer a low-grade fever, chills, headache, muscle aches and a general sense of fatigue. Widespread respiratory illnesses sometimes occur on ships due to the close quarters. Dr. Olds advises cruise passengers to select a cruise line that has been certified by the CDC.

Deep Vein Thrombosis
Although the food and water in Europe, Canada, Japan and Australia are considered safe, any travel that requires a long flight poses the risk of deep vein thrombosis (DVT), in which a blood clot develops in the leg or pelvic veins. If the clot breaks off and travels through the blood stream, it can lodge in the brain, lungs, heart or elsewhere, causing severe damage to the affected organ. DVT can be averted with a few simple steps, Dr. Olds says:

"Once an hour, get up and move around. Walk up and down the aisles. And while seated, there are exercises you can do to keep blood circulating." Travelers at risk of fluid retention and those with hypertension or diabetes should consult with their physicians about any adjustments they should make to their regular medications before making a long flight, he says. Some doctors advise people facing long flights to take a low-dose aspirin to prevent DVT.

Of herbal medications that claim to prevent jet lag, he warns: "Remember, even herbals have active ingredients. So check with your physician or travelers' clinic to make sure these preparations won't interfere with any medications you normally take."

Who's at Risk?
Which travelers are at special risk? According to the CDC, those at particular high-risk for travelers' diarrhea include young adults, immunosuppressed persons (such as those undergoing chemotherapy or who have HIV), those with inflammatory-bowel disease or diabetes, and those taking H-2 blockers or antacids. Breast-fed infants 6 months old or younger are generally protected by their mothers' immune systems, Dr. Olds says, but children 6 to 9 months old are at greater risk because they begin to lose the immunity they got from their mothers, and they're beginning to nibble on a variety of foods. Older adults are often safer than teens and young adults, because older people tend to heed warnings better, he notes.

"Many primary care physicians are not fully aware of the health risks of international travel," Dr. Olds says, noting that it's a fast-changing field. He advises travelers going outside the United States to visit a clinic that specializes in international health before they depart. The Medical College of Wisconsin operates an International Travelers Clinic in the Froedtert East Clinic, offering consultations and immunizations or medications tourists might need to stay healthy while traveling abroad.

For a consultation at the Medical College International Travelers Clinic, call 414-805-6679.

Barbara Abel
HealthLink Contributing Writer

For more information on this topic, see the HealthLink articles Good Food – and Why It Can Make Us Sick and Mexican Vacation Requires Some Health Planning.