Water-borne diseases

Water-borne diseases are a major cause for concern, especially among children — more so, among the poor communities in the developing world where clean, potable water is scarce.

The problem is only being accentuated with depletion of water resources, global warming, unprecedented growth of cities and pressures of globalisation and commercialisation of water supply.

Water-borne diseases affect nearly four billion people every year, with more than 2.5 million deaths, most of them among poor children. Water-borne infections of the alimentary tract constitute about 3.7 per cent of the global burden of disease, the sixth highest burden on a global scale. And, if one also considers other water-related diseases like helminthiasis [worms] and diseases spread by mosquitoes that breed in stagnant water, the burden looks staggering.

Preventable problems

Yet, all this is preventable with well-planned and careful management of water usage. Although mortality rates have declined in recent years, owing to improved sanitation and better healthcare, much needs to be done with almost one-sixth of humanity lacking access to clean water.

There is nothing we can do without water. Apart from its need for drinking and preparation of food, water is also needed for cleansing and recreational activities. The worst part – water stagnation anywhere in the vicinity of human dwellings can be a source of disease-carrying insects.

Water-related infections can, therefore, manifest on account of consumption of contaminated water, inadequate personal hygiene and through intermediate hosts of microbes that thrive in water, or insect vectors that breed in water.

Come summer, the squelching heat increases the demand for water on the one hand – scarcity of water forces the use of unpotable water, on the other. Also, the advent of monsoon leads to water stagnation everywhere, providing a fertile breeding ground for vectors of human disease. It’s no surprise that water-borne diseases increase manifold in either conditions.

Many infections of the gastro-intestinal tract result from drinking contaminated water. While natural water bodies like wells, ponds, lakes, rivers, and even ground water provide the “soil” for microbes to thrive, most naturally-occurring microbes do not cause any illness.

Disease-causing microbes or harmful chemicals can contaminate water through discharge or seepage of untreated sewage or domestic and animal wastes into water bodies, storage tanks, or distribution lines. Improper storage of drinking water also promotes multiplication of disease-causing germs and is an important source of infections in cities.

Microbial battlefield

Although there are many microbes that are spread through water [faeco-oral route], it is viruses like hepatitis A and E, rotavirus and norovirus, bacteria like Salmonella, Shigella, Campylobacter, E coli and Vibrio cholera, parasites like Giardia, Entamoeba and Cryptosporidium and helminths like Schistosoma that cause most of the water-borne infections.

Norovirus is an emerging viral disease that is now blamed for almost 50 per cent of all cases of diarrhoea worldwide.

Most infections of the gastro-intestinal tract manifest with abdominal discomfort or pain associated with a bloating sensation, followed by vomiting and/or diarrhoea, sometimes with stools mixed with blood. Some may also have fever and other bodily symptoms too. The severity and duration of the symptoms depend on the causative agent.

While most cases are self-limiting and improve within 5-7 days, patients with profuse diarrhoea may succumb if adequate fluid replacement is not provided. Young children, the elderly and immuno-compromised patients are at special risk of developing life-threatening complications and accordingly merit special attention. The passage of many watery stools, repeated vomiting and failure to eat or drink normally, dizziness on standing and increased thirst are indications for more aggressive fluid replacement and even hospitalisation.

Gruels, carrot soup, rice water [congee], fresh fruit juice, weak tea, tender coconut water, a salt-sugar-water solution, oral rehydration solution, or if nothing is available, clean water can all be used for rehydration. Normal food should be continued to maintain nutrition in all such cases.

Use of anti-diarrhoeals to abruptly stop diarrhoea is not proven to be beneficial and may cause harm if used in children. Use of specific anti-microbial drugs is warranted only in cases such as suspected cholera, traveller’s diarrhoea, patients with high grade fever or blood in stools and/or in proven bacterial or protozoal infections.

Hepatitis viruses A and E are also transmitted through the faeco-oral route and cause brief febrile illness followed by yellowish discolouration of eyes and skin [jaundice].

Leptospirosis, more commonly known as Rat Fever, is a multi-system illness caused by a spiral bacteria called Leptospira. Common in rural parts of India, it is contracted through wading or bathing in water bodies contaminated with urine of infected rats. In most cases, leptospirosis passes off as a minor illness; however, in some, it can cause complications like liver and kidney failure that may be fatal.

Other dangers

Recreational water illnesses are spread by swallowing, breathing, or having contact with contaminated water from swimming pools, spas, or natural water bodies. Swimming, when ill, with diarrhoea can easily contaminate large pools or water parks. Apart from gastro-intestinal infections, recreational water illnesses can involve skin, ear, eye, respiratory, or the nervous systems, and some of these may be fatal.

Mosquitoes breed in stagnant water and mosquito-borne diseases are on the rise all over the world. Malaria, dengue, chikungunya, West Nile encephalitis, Japanese encephalitis and many others have become formidable challenges to mankind.

If mankind has to survive this “watery grave,” concerted efforts are needed towards scientific management of water resources and cleanliness.