In a recent issue, I discussed the importance of preventing dehydration while traveling (“Risk on the Road,” Global Traveler, August 2004). The tsunami disaster that recently hit southern Asia, Africa and Indonesia is a clear demonstration of the importance of fresh water. As I write this column, my heart goes out to the victims who lost their lives or are struggling to survive in the wake of this overwhelming natural disaster.

Survivors face the continued threat of disease. Inadequate sanitation and contaminated water are the vehicles for transmission of such serious maladies as cholera, hepatitis A, diarrhea, dysentery, typhoid fever and malaria. While the potential for exposure to these diseases is now heightened in areas recovering from the tsunami, the threat is real for travelers to almost any underdeveloped nation. Many countries do not have the same sanitation requirements as the United States, but even with those safeguards, severe gastrointestinal illnesses caused by water-borne agents sometimes strike.

To protect yourself, give careful consideration to any water you ingest, including water used while brushing your teeth, washing dishes or making ice. Water that has been adequately chlorinated according to U.S. minimum standards should be free from viral and bacterial diseases, but chlorination will not provide the protection needed against some enteric and parasitic organisms. If traveling to areas where chlorination is not available and where sanitation is poor, stick to beverages made with boiled or boiling water (hot coffee or tea), or canned and bottled beverages.

Never use ice made from water that may be contaminated. If possibly contaminated ice has been in contact with drinking containers, those containers should be thoroughly washed before use. In most cases, it’s safer to drink directly from a bottle or can than to use a glass or cup that may not have been properly washed. Still, even the outside of a commercially bottled beverage may be contaminated. Dry the outside of all wet bottles or cans prior to use and carefully wipe the area where you mouth will have contact with the beverage container.

Keep in mind these four basic guidelines:

– Drink bottled water.
– Boil water before drinking.
– Use chemical disinfectants.
– Use water filtration/purification systems.
– Bottled water is usually a dependable choice provided the seal on the cap is intact.

If you opt to boil water, do so for at least three minutes, and allow it to cool before drinking. Chemical disinfectants may be used when boiling water is not possible, but the method is slow. Water must stand for 15 hours after the iodine tablets have been added in order to kill the parasitic organism Cryptosporidium, which if ingested will cause acute illness and diarrhea. Water can be filtered using the portable filters readily available, but read labels carefully to be sure you select a filter specifically designed to kill Cryptosporidium and another parasite, Giardia. (Further information is available on the Web site of NSF International, a nonprofit health and safety company, www.NSF.org/certified/DWTU.)

Proper selection, operation, care and maintenance of the filtering system are key to producing safe water while traveling. The manufacturer’s guidelines must be followed at all times. Remember that filters do collect the organisms from the water, so you should wear gloves when changing cartridges, and wash your hands thoroughly afterward. Follow the manufacturer’s guidelines for when to change the filters. The filtering system can easily fail when the system is poorly maintained. If the system fails, you could become ill.

For many travelers, the best opton is a portable water purifier, which filters the water without the delay required for the addition of iodine tablets. A variety of portable, easy-to-pack water filtration systems are available, offering varying levels of water purification and protection from the many disease-causing organisms. Some of these systems have iodine within the filter cartridges. Good systems range in cost from $50 to $250. Be cautious of labels that say EPA approved or certified. The Environmental Protection Agency does not approve or test filters.

Interestingly, there are very few published scientific research studies that have evaluated specific brands or models of filters for the removal of bactiera and viruses. Until more studies are completed, the Centers for Disease Control and Prevention cannot rank filters based on that criteria. The CDC does, however, have information on filters and their effective removal of Cryptosporidium and Giardia. A traveler’s guide to buying water filters to prevent consuming these parasites in water can be found at www.cdc.gov/ncidod/dpd/parasites/cryptosporidiosis/factsht_crypto_prevent_water.htm.