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Diseases caused by dirty water and unsanitary conditions are one of the leading causes of death. There are, however, a number of ways to contain epidemics and prevent certain diseases. Professor Piarroux*, a specialist in infectious diseases and tropical medicine, answers questions SOLIDARITÉS INTERNATIONAL’s questions.
(Interview conducted by Jean-Marc Leblanc, Water, Hygiene and Sanitation advisor, SOLIDARITÉS INTERNATIONAL)
Which of the diseases related to water and unsanitary conditions are the most lethal?
The deadliest diseases are those which are linked to water consumption (e.g. diarrhoeal diseases, typhoid fever, and hepatitis). These are followed closely by vector-borne diseases (e.g. malaria) for which water is the breeding ground, especially in the case of the mosquito. There are also illnesses caused by a lack of water, such as cholera, where the high concentration of people at residual water points facilitates transmission. Then there is trachoma, a disease caught by rubbing the eyes with dirty hands, causing the eyelids to become infected and the eyelashes to damage the cornea, causing blindness. Lastly, there are diseases contracted through contact with water, such as bilharzia, which have a lower mortality rate.
A number of these diseases are easy to treat and prevent. Why are there still millions of victims?
Water-borne diseases are easy to treat when there is a doctor close by and an efficient healthcare system. When people are unaware, for example, that oral rehydration is effective in combating diarrhoeal disease, it’s more complicated. And even when people know that water should be chlorinated and that they should seek treatment if they experience diarrhoea, they don’t always have the financial means to do so.
Why are water and sanitation so vital in disease prevention?
It is very important to act pre-emptively. Activities including awareness-raising, information dissemination and improving access to drinking water are essential. The distribution of chlorine tablets is extremely beneficial when water resources are contaminated by germs. Finally, efforts to raise awareness among decision-makers, like those of SOLIDARITÉS INTERNATIONAL, are equally important.
How can we improve the situation even further?
Raising awareness of the importance of hand-washing, information sessions, and improving access to water and ways to make it drinkable (through chlorination), all have an important role to play: but these don’t always prevent epidemics. To be truly effective, actors must have the ability to analyse, especially through epidemiological investigation. Action on the ground should always be guided by epidemiology. These two battles are less effective if carried out separately.
Could pressure on certain ecosystems promote the transmission and outbreak of certain diseases, especially those linked to water?
The pressure placed on forest ecosystems is blamed for the emergence of diseases such as Ebola, but it can’t be held responsible for the spread of water-borne diseases such as cholera. On the other hand, when our relationship with water changes, it encourages the emergence of bacteria and parasites which take advantage of one system to the detriment of another.
Biography : Renaud Piarroux is a professor at the University of Aix-Marseille and Departmental Head of Parasitology and Mycology for the Marseille Hospitals Authority. A paediatrician and specialist in infectious diseases and tropical medicine, he is also an expert on cholera.
Cholera : the “dirty-hands disease”
Over the past few centuries, cholera has spread from its original breeding ground in the Ganges-Brahmaputra delta in Bengal, to the rest of the world. Highly contagious and often fatal if left untreated, cholera is transmitted orally though water, food and dirty hands. It results from a lack of hygiene as well as a lack of knowledge about the disease. Cholera causes the body to lose water and electrolytes (e.g. the ions contained in salt) through diarrhoea and vomiting. A person can lose up to 10% of his or her body weight in 24 hours. It is therefore necessary to replace the water and electrolytes lost through rehydration. Fresh contamination can be prevented by the adoption of good hygiene practises, by both individuals (e.g. hand-washing, treatment of drinking water, defecation in latrines) and communities (e.g. provision of drinking water, management of excrement).
“To put an end to cholera, we must eradicate it in the places where it already exists,” explains Professor Piarroux. “It is the human carriers of Vibrio Cholerae, the bacteria responsible for the disease, who spread it in unaffected regions.“