Most people who live in the developed world take the safety of their drinking water for granted. One turns on the tap, and clean, potable water pours forth. However, the cleanliness of the drinking water depends on millions of dollars in infrastructure and decades of stable government regulations, and vacationers traveling abroad will soon discover that untreated water can have dramatic effects. As a result of drinking untreated water or eating food washed in it, roughly 10 million people become ill every year. The figure encompasses somewhere between 20 and 50 percent of travelers.
Untreated water typically carries a variety of organisms, including strains of bacteria, protozoa, and viruses. While the occasional unlucky traveler may come down with a case of dysentery or typhoid fever from drinking unclean water, most will simply be afflicted with traveler’s diarrhea or TD. Individuals with compromised immune systems, pregnant women, and others who fall into high-risk categories are more susceptible to various other waterborne pathogens. Luckily, most of this risk can be avoided with some planning and vigilance.
The first and most obvious step is to avoid drinking unpurified water or eating any foods that have been prepared with tap water. This can include everything ranging from unpasteurized juices, salads, uncooked foods, and teas. Whenever possible, you should stick to bottled water, ideally one that has a factory seal that has been opened in front of you. Look for labels indicating that the water has been approved by the International Bottled Water Association. However, you should plan for the worst. Pack water disinfectants or an excellent filter, and bring all water to a roiling boil before use. You should also be wary of water in other settings. Swimming in an unclean lake or river is a risky choice, as is brushing your teeth with tap water. People who are at the highest risk of illness will also want to be cautious about showering, keeping their mouths closed, and covering open wounds.