Standards

• For a purifier, filter or chemical treatment to be marketed and sold as water treatment systems, the devices or chemicals must be able to kill 99.9999 percent of bacteria, 99.99 percent of viruses and 99.9 percent of protozoa, under the U.S. Environmental Protection Agency Guide Standard and Protocol for Testing Microbiological Water Purifiers. Read the product's label to ensure they meet EPA guidelines.
  
  

Necessity

• One of the leading causes of illness for travelers is drinking contaminated water. The result could range from mild gastrointestinal distress such as an upset stomach to vomiting to serious bacterial diseases. Water-borne illness is usually caused by E. coli, cholera, salmonella, protozoa like cryptosporidium, viruses or chemical pollutants. Sometimes, however, travelers fall ill from drinking water whilst traveling internationally because the pathogens in the local water are immune to their systems and their bodies have been unable to adapt.
  
  

Identification

• For many Western travelers, third-world and developing countries' waters may cause illness if not treated prior to drinking. Mexico is well known for its unsafe water, as is the rest of Central America, most of Africa and Asia and the Middle East. There are moderate risks to drinking local water in Eastern Europe, Russia, South Africa, Argentina, Chile and some parts of the Caribbean. Places where it is usually safe to drink local water are in developed parts of the world like the United States, Canada, Australia, New Zealand, Northern and Western Europe, many parts of the Caribbean and Japan.
  
  

Treatment

• Travelers who find themselves in a place with unsafe water can treat it two ways: chemically and mechanically. There are numerous chemical treatments for sterilizing water. There are SteriPens, which use short-wave ultraviolet light to disrupt viruses' DNA, making them unable to reproduce and cause illness. Travelers can also use mixed oxidant devices that electronically charge salt-based solutions which are then poured into water to neutralise pathogens. Lastly, there are chlorine dioxide tablets that kill waterborne viruses and Cryptosporidium when mixed with unsanitary water. Typically, one tablet can treat 1 quart of water.
  
  

Mechanical Filters

• For travelers who do not want a chemical taste in the water after treatment, they can use mechanical filters. Not all mechanical filters can remove all the organisms that cause illness. However, there are carbon-based filters that filter out bacteria, protozoa, cysts and viruses. Travelers who are unsure whether they've filtered out all the harmful bacteria and viruses can always boil the water filtration just to make sure.
  
  

Effects

• Travelers who fail to treat water prior to drinking may fall ill. Symptoms of water-borne illness include diarrhea, vomiting, nausea, fever, aches and/or chills. If they are not due to more severe illnesses, these symptoms will usually clear up after a few days. If they don't go away or they worsen, travelers are advised to seek medical help. Otherwise, ill traveler's can take anti-diarrhea medication and stay hydrated by drinking sports drinks and bottled water.