Simple advice to avoid illness when traveling abroad

Insect repellent is important when visiting the developing world.
Washington Post
WASHINGTON -- The best advice to avoid getting sick on overseas trips appears to be simple: Use insect repellant, watch what you eat and take your malaria pills.
Malaria and dengue -- both transmitted by mosquitoes -- are the two biggest causes of fever in travelers who become ill after traveling in the developing world, according to a new study. Leishmaniasis, passed by sand flies, and rickettsial infections, transmitted by ticks, are much less common but hardly unknown.
Diarrhea is second only to fever among the most common illnesses afflicting returning travelers. Skin problems are third, with insect bites and hookworm infections predominating.
New study
The new study is the largest effort by far to describe the spectrum of travel-related illness, and also the first to sample patients seen in many countries. It appeared recently in the New England Journal of Medicine.
"If you are careful about what you put in your mouth, and if you are careful about using mosquito repellant, you can dramatically reduce the risk of the most common illnesses," said David Freedman, the report's lead author and a physician at the University of Alabama at Birmingham.
He heads the GeoSentinel Surveillance Network, a consortium of 30 travel and tropical medicine clinics on six continents where the data were collected.
Incomplete picture
Although the most comprehensive of its kind, the study gives an incomplete picture of the hazards of leaving home. It captures only the problems treated after the traveler returned and not during the trip.
Previous studies showed that heart attacks and stroke, and trauma (mostly from car accidents), are the main cause of death among travelers. Overall, three to four times as many men as women die abroad.
The new study describes the experiences of 17,353 patients. Their average age was 33; half were women.
Nearly 60 percent had gone overseas as tourists, not for business or education.
Nearly two-thirds visited one of the clinics in the network less than a month after getting home. Ten percent did not seek treatment until more than six months later.
Out of every 1,000 patients, 226 had illnesses whose most prominent sign was fever; 222 had acute diarrhea; 170 had skin diseases; 113 had chronic diarrhea; 82 had other intestinal problems; and 77 had respiratory disorders.
Location matters
A chief advantage of the study over previous ones is that it shows how the likelihood of a complaint or disease varies depending where a traveler went.
For example, fever-based ailments were more than twice as common in patients who had visited sub-Saharan Africa as in those whose destination was in Central or South America.
Malaria was the overwhelming cause of those fevers in travelers to Africa.
But in people who had gone to Latin America, the cause of fevers was as likely to be dengue as malaria. In returnees from Southeast Asia, fevers were twice as likely to be the result of dengue.
The parasitic skin infection leishmaniasis was twice as common in people who visited South America as in those who went to Central America -- and was virtually unheard of in visitors to the Caribbean and to Africa.
But physicians can expect to see four times as many cases of "cutaneous larva migrans," a skin ailment caused by a hookworm found in animal feces, in Caribbean visitors as in travelers to south-central Asia.
The journal paper includes a chart listing the world's regions and the relative likelihood of seeing various ailments in travelers returning from them.
Freedman believes the chart may be useful to doctors and nurses in travel clinics.
"It will help physicians make rapid and accurate diagnoses. If a patient has been to South America they can say, okay, these are the 10 most common things. It may help them to know what tests to order, and what therapies they should try first if it's something they can't diagnose immediately," he said.
Updates needed
The findings will have to be updated periodically, because the mix of ailments can change as both the ecology of disease and the patterns of human travel evolve.
Dengue, known as "breakbone fever" because of the intense muscle and joint pain it causes, is on the rise in many places because the geographic range of the Aedes aegypti mosquitoes that transmit it is getting larger.
However, more travelers to South America are contracting leishmaniasis because they are going to remote areas where it is prevalent. Hot spots include two popular ecotourism destinations, Madidi National Park in Bolivia and Manu National Park in Peru, both in the Amazon basin.
Exotic infectious diseases, however, are not the deadliest threat to travelers.
A study published 15 years ago found that 49 percent of deaths of U.S. travelers were caused by heart attacks or strokes suffered abroad and 25 percent by injuries, primarily in car accidents.
A study of deaths among Australian travelers over a 12-month period found that 35 percent were caused by heart disease and 18 percent by injuries, but only 2 percent by infection.