The most common diseases affecting international travellers are those related to contaminated water consumption, such as traveller’s diarrhoea, typhoid fever, or hepatitis A. One of the main recommendations to avoid infection is to drink only bottled water during your trip. However, this is sometimes not possible, either because of a shortage or because it does not come from a reliable source. This is especially common in developing countries, where health services are poor, or on adventure travel, where you can spend days or weeks away from urban areas.
In cases like these, it is recommended to disinfect the available water to eliminate bacteria, viruses, protozoa or helminths (parasites). There are different methods you can use to prevent infection, such as the following:
Boil water
According to the Center for Disease Control and Prevention (CDC), common intestinal pathogens can be inactivated quickly through heat. It is recommended to boil water for at least 60 seconds and let it cool before drinking. One of the advantages of this method is that it does not change the taste of the water and is accessible.
Filter water
There are a variety of filters available in camping tents. These devices can remove bacteria, however, they may not be effective in removing viruses from water. The advantage of filters is that they are portable, however, they require maintenance.
Chemical water disinfection
Another option that is convenient for people in rural areas is disinfection tablets. They commonly contain chlorine or silver, in addition to a substance that improves the taste of water. CDC and the World Health Organization recommend the use of sodium hypochlorite to disinfect water with a concentration of 0.5 to 1%. It is important to follow the instructions on the disinfection packs carefully. They usually destroy most bacteria, when used as indicated (e.g. Vibrio cholerae), but they are less effective for viruses and cysts (e.g. hepatitis A virus, giardia and amoebic cysts, cryptosporidium).
Chlorine Dioxide
Chlorine dioxide is the most recommended method and is available in tablet or droplet form. It is cheap, safe and effective. Do not confuse it with chlorine or iodine as it is not the same and in fact, it is free from both of these elements. Chlorine dioxide will kill bacteria, viruses and cysts in water (including giardia and cryptosporidium). It is tasteless and odourless.
Please be aware that iodine is no longer recommended for the purpose of water purification
Use of UV rays
The effectiveness of this method depends on the length of time the water is exposed to UV light, but it may be an appropriate disinfection technique when the amount of water is reduced.
There are portable units that are effective against all pathogens, however, it works only with water that does not contain solid residues as these could cover the microorganisms in the light. The sun’s rays can also be used to disinfect water, however, the liquid must be crystalline and the climatic conditions must be suitable. This process could take hours or even days.
Before heading to a destination where the availability of purified water cannot be guaranteed, make sure you have one or more methods of disinfection so that your holiday is not ruined by a doctor’s visit or worse.