It is important to abstain from alco hol consumption when engaging in swimming or boating activities. Other dangers that tourists traveling to developing countries can encounter include parasites that penetrate the skin of bare feet and other exposed body areas. It is important for this reason to always wear shoes. Avoid swimming in freshwater lakes or rivers. In many areas swimming in them can lead to skin penetrations and infection of parasites.
Altitude illness is caused by a diminished supply of oxygen at higher elevations.
The incidence of altitude illness depends on the rate of ascent. Tourists to high-altitude destinations may experience rapid and significant changes in altitude, reaching an altitude of 12,000 feet or more within a day after leaving a comfortable low altitude. Slow ascent is the key of effective acclimatization and prevention of serious illness. The altitude at which the climber sleeps is the most important factor. If possible, try to avoid sleeping above 10,000 feet the first night.