Risk for Travelers

Waterborne disease is a risk for international travelers who visit countries that have poor hygiene and inadequate sanitation, and for wilderness users relying on surface water in any country, including the United States. Worldwide, more than one billion people have no access to potable water and 2.4 billion do not have adequate sanitation. In developing countries, the influence of high-density population and rampant pollution, along with absent, overwhelmed, or insufficient sanitation and water treatment systems, means that surface water may be highly polluted with human waste and even urban tap water may become contaminated. Primarily humans, but also animals, are the source of microorganisms that contaminate water sources and cause intestinal infections.

The list of potential waterborne pathogens is extensive and includes bacteria, viruses, protozoa, and parasitic helminths. Most of the organisms that can cause travelers’ diarrhea can be waterborne, although the majority of travelers’ intestinal infections are probably transmitted by food. Microorganisms with small infectious doses can even cause illness through recreational water exposure, via inadvertent water ingestion.

Bottled water has become the convenient solution for most travelers, but in some places, it may not be superior to tap water. Moreover, the plastic bottles create a huge ecological problem, since most developing countries do not recycle plastic bottles. All international travelers, especially long-term travelers or expatriates, should become familiar with and utilize simple methods to ensure safe drinking water. Disinfection, the desired result of field water treatment, means the removal or destruction of harmful microorganisms. The goal of disinfection is to reduce the risk of gastrointestinal infection and diarrheal illness. Table 2-28 compares benefits and limitations of different methods.