To complicate matters, the guides on these adventure trips can have varying degrees of experience and judgment. In just the past year, Bellis participated in mountain climbing expeditions in Tibet and Russia, and on both occasions, she treated fellow climbers who had developed moderate to severe altitude sickness. In each case, she recalls, the guides had exceeded the appropriate rate of ascent. Once, when a climber had become ill, the guide hesitated to order the proper procedure - an immediate descent from the mountain - to keep from spoiling the trip for the rest of the group.
"Generally, these guides are kind people who very much want to make sure that their groups have a good holiday," says Bellis. "They find themselves in the dilemma of needing to take one person down the mountain, which may mean the entire group has to descend as well."
If the high altitudes of some adventure travel don't get you, the infections might. Diseases with names such as leishmaniasis (caused by sand fly bites), and leptospirosis and schistosomiasis (both related to contaminated water) can be contracted by tourists in remote locales.
In one of the largest recorded recent outbreaks, about half of more than 150 participants in a multisport expedition called Eco-Challenge-Sabah 2000 in Malaysian Borneo contracted leptospirosis, developing symptoms such as fever, headaches, chills, and muscle aches. Investigators at the CDC concluded that these individuals, who participated in several grueling days of canoe paddling, open water swimming, and mountain biking, may have become infected while swimming or paddling in the Segama River, and inadvertently swallowing water contaminated by Leptospira organisms from the urine of infected animals. If untreated with antibiotics (such as doxycycline), leptospirosis can lead to kidney damage, liver failure, meningitis, and in rare cases, death.
According to Kozarsky, president-elect of the International Society of Travel Medicine (ISTM), there have been recent outbreaks of diseases such as schistosomiasis in people who have rafted down the rivers in Ethiopia, and histoplasmosis (a fungal infection) in groups who have gone into caves in Nicaragua. "None of these people was told ahead of time that there might be health risks," she says.