Water-borne diseases include dysentery, cholera, typhoid fever and a wide range of other parasitic infections.
These diseases kill more than a million people each year, many of them children in developing countries.
People can contract these diseases when they drink water that contains dangerous microorganisms, including viruses, bacteria, single-celled organisms called protozoa and larger parasites such as worms.
Water-borne diseases can also occur if people eat food that has been prepared using contaminated water, or when parasites enter the body directly through an open wound.
The most common causes of water-borne disease are unclean water supplies, inadequate sanitation and poor hygiene.
Many water-borne diseases can be fatal, especially to the very old or very young. Non-fatal infections can cause extreme discomfort and a wide range of symptoms that include nausea, vomiting and diarrhea.
Water-borne diseases can become major problems after natural disasters if large numbers are forced to live temporarily in crowded areas with poor sanitation and limited supplied of safe water.
Research suggests that, in some settings, climate change could affect water-borne diseases, because changes in temperature and rainfall can affect the survival of disease-causing organisms.
Clean water, good sanitation and hygiene are needed to limit the threats that water-borne diseases pose.
For households, this means having effective water and sanitation systems. These must ensure that drinking water supplies are protected from contamination, and that sewage is removed and treated in a way that prevents it coming into direct contact with people.
Many people in developing nations rely on wells rather than piped-water supplies. For them and for people whose piped water is unsafe, it may be necessary to treat the water at the point of use to destroy any dangerous organisms.
People can make water safe by boiling it, treating it with chemicals such as chlorine, using sunlight to kill microorganisms or by using specialized filters that capture dangerous pathogens.
The World Health Organization has detailed information on water, sanitation and hygiene, and a dedicated mailing list which journalists can join to information and to interact with specialists.
Another valuable source for journalists is the International Institute for Sustainable Development’s Water-L list, an email based discussion group for policymakers, nongovernmental organizations, journalists and others who are interested in water issues.
Good news pegs for stories — and sources of new stories — on water-borne diseases include the annual World Water Week and the World Water Council ‘s (WWC) World Water Forum, which takes place every three years. Both are major international conferences.
The WWC’s media website has contact details of water experts, story ideas and a photo / video gallery for media use.
For new research on water-borne diseases, journalists can subscribe to the press releases from key medical journals such as The Lancet and The Lancet Infectious Diseases, BMJ and the Journal of the American Medical Association.
CASE STUDY – Cholera in Zimbabwe
In 2008 a major cholera epidemic began in Zimbabwe and soon spread to other countries (Zambia, Botswana, Mozambique and South Africa). The deadly disease is caused by a bacterium that infects the intestine and causes vomiting and diarrhea.
A major contributor to the emergence and spread of the disease was the lack of safe water in urban areas of Zimbabwe, due to poor sanitation and waste management, and limited supplies of clean piped water.
These factors, combined with the start of the rainy season, meant that large amounts of contaminated human feces entered water supplies. Zimbabwe had inadequate supplies of chemicals such as chlorine to purify water and its poorest citizens could not afford firewood with which to boil water to make it safe to drink.
The epidemic began to spread from urban to rural areas as people traveled or sent corpses home for burial. By January 2010 there had been 98,741 reported cases across the region, and 4,293 deaths. This makes it the deadliest African cholera outbreak for some 15 years.