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Health
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Edition 25: Autumn 2003
Among travellers, diarrhoea is the great equaliser. It hardly matters how much you spend on your holiday.
In the West we take it for granted that the piped water supply is automatically safe, as if almost by magic. In most developing countries around the world such assumptions are unfounded. The liquid that comes out of the tap must be regarded as a very dilute solution of sewage until proven otherwise. An astonishing array of microbes can be transmitted in drinking water, causing illnesses that range from dysentery to hepatitis A. But the steps needed to make water safe are the same. Here are some of the simplest and commonest:
Bottled water. Water from a hygienic or mineral source, bottled, sealed and transported without tampering or contamination, is safe to drink. In some countries the relatively high value of such water makes it an easy target for fraud. Unless you are being supplied with a recognisable brand, with the seal broken in your presence, still bottled water should be regarded with caution. Carbonated water is less easy to tamper with and the carbon dioxide in solution affords the additional protection of a mild sterilising effect.
Boiling. At first sight this might seem impractical, but in an urban setting tea and coffee are very widely available. Although strong tea and coffee can have a diuretic effect, resulting in net water loss, weak tea and weak instant coffee can be good sources of fluid. For hygiene, it is helpful to rinse out the cup (and especially its rim) with boiling water or, if this is not possible, to tip out some of the drink to cleanse the part of the rim that you put to your mouth.
Chemical purification. Iodine is more effective than chlorine and is my own preferred option by far. I tend to use drops of iodine tincture rather than iodine tablets. The main reason is that tablets generally need to be made up to fixed quantities of one litre at a time, whereas, with drops, water can be purified by the cup. Some of the iodine tablet preparations include neutralisers that remove iodine from solution once its work has been done, also removing the taste. During many months spent travelling in Africa I became quite partial to the taste! It's easily avoided, however, by adding a squeeze of lemon or lime (though only after the iodine has been allowed to take effect).
Solar disinfection. Ultraviolet rays can be harnessed to purify water. This can be done in plastic soft drink bottles (ideally painted black on one side). Under hot, sunny conditions purification can be achieved within six hours.
Purification devices. There is a wide choice on the market. Almost all of them incorporate some kind of combination of filtration mechanism (for removing suspended particles) and chemical exposure (to kill microbes). They differ in their sophistication, capacity, size, weight, cost and efficacy. A full review can be found in Travellers' Health (OUP, £14.99). Apart from choosing one that matches your requirements in these parameters, look for evidence that the device has been tested independently and be sure to discard the unit well within its advertised lifespan.
Of course, the same safety considerations also apply to ice. Ice can only be as safe as the water from which it is made. An additional risk arises, however, because ice machines easily become contaminated with bacteria and viruses; such contamination is difficult to eradicate even under first world conditions.
There are other ways for water to transmit disease and in Africa the most important of these is through direct skin contact. Bilharzia (also known as schistosomiasis) is a parasitic infection that exacts a terrible toll across almost the entire continent. Any body of fresh water is capable of harbouring the infection, so swimming and water sports in rivers, lakes, streams and waterholes are best avoided, even in the face of local advice to the contrary (infection may take months or years to become apparent, so local people do not necessarily know about the consequences for travellers). If you are undeterred by the risk of bilharzia, keep in mind the risk of being eaten by crocodiles: the annual death toll from the Nile crocodile exceeds 1000! |
