When water kills
Waterborne diseases are diseases transmitted through drinking water contaminated with pathogenic microorganisms such as protozoa, viruses, bacteria, and intestinal parasites. Most waterborne diseases are characterised by diarrhoea and can result in dehydration and even death in very serious cases.
How does water get contaminated?
Poor personal hygiene practices like preparing, eating or handling food and water without washing hands well after defecation can lead to contamination due to faecal matter that contains disease-causing microorganisms. Contamination can also occur at the source or while transmitting water through pipes that are located close to sewage lines. This can lead to the mixing of sewage with drinking water, contaminating it with disease-causing microorganisms. Other factors such as inadequate water supply, poor sanitary conditions, uncovered sources of drinking water, defecation in the open near sources of drinking water, poor systems for human waste disposal and a lack of awareness among populations can increase chances of contamination. Natural disasters such as floods can also trigger epidemics of water borne diseases due to mixing of sewage with drinking water sources, drinking of contaminated water due to destruction of safe sources of drinking water.
Why should waterborne diseases be taken seriously?
Waterborne diseases are a serious problem from the public health point of view as they can spread rapidly affecting large sections of the population, lead to a very high disease burden and have a major impact on the economy in countries such as India where water pollution and open defecation, coupled with poor sanitation and hygiene practices lead to high incidence of waterborne diseases.
What are the types of waterborne diseases?
Waterborne diseases can be classified based on the causative agent and the modes of transmission.
Diarrhoeal diseases
: Can be caused by a host of bacterial, viral and parasitic organisms resulting in frequent passage of acute watery diarrhoea or bloody stools over days or weeks. Infectious agents that cause diarrhoea are often transmitted through the faeco-oral route. Severe diarrhoea can be life threatening if not treated in time and can lead to dehydration, particularly in infants and young children.Read more here
Some of the common diarrhoeal diseases in India include:
Cholera
: Is an intestinal infection caused by the bacteria Vibrio cholera acquired through infected food and water leading to massive watery diarrhoea, vomiting, cramps and dehydration.Read more here
Giardiasis
: Is caused by the parasite Giardia intestinalis that enters the human body through the ingestion of parasite cysts that can be present in unfiltered or untreated drinking water or contaminated food.Read more here
Amoebiasis
: Is caused by a parasite Entamoeba histolytica and is transmitted through person-to-person contact or through eating or drinking of faecally contaminated food or water.Read more here
Bacillary dysentery
: Is caused by Shigella, Campylobacter, E. coli, and Salmonella species of bacteria. Symptoms of dysentery include diarrhoea with blood or mucus, cramps in the stomach, nausea, vomiting and fever. Poor sanitation and infected faeces can contaminate water or food and cause dysentery.Read more here
Other infections include:
Typhoid and Paratyphoid
: Are associated with poor sanitation and untreated water supplies. Typhoid is caused by the bacteria Salmonella Typhi while Paratyphoid is caused due to the infection of Salmonella Paratyphi A.Read more here
Hepatitis A and E
: Are viral diseases caused by the ingestion of contaminated food or water or through direct contact with an infected person. Both affect the liver and can cause mild to severe illness.Read more about Hepatitis A here
Read more about Hepatitis E here
Guinea worm infection
: Is caused by the parasitic worm Dracunculus medinensis which lodges itself in the body of cyclops or water fleas found in the water and can enter the human body through drinking of untreated or contaminated water from ponds or shallow open wells.Read more here
Read more about waterborne diseases here
Waterborne diseases globally
Four percent of global deaths and 5.7 percent of the global disease burden is caused by infectious diseases related to water, sanitation, and hygiene (WASH). Only 19 percent of the world population washes hands with soap and water after contact with excreta, 26 percent people drink water that is occasionally contaminated with faecal bacteria.
As high as 1.9 billion people worldwide use either an unimproved source or an improved source of water that is faecally contaminated, mostly groundwater and rural piped supplies. Microbial contamination of water is widespread in lower- and middle-income countries with faecal contamination being the most prevalent in Africa and Southeast Asia.
Waterborne diseases in India
Annually about 37.7 million Indians are affected by waterborne diseases, 1.5 million children die of diarrhoea and 73 million working days are lost leading to an economic burden of $600 million a year.
Waterborne diseases such as cholera, acute diarrhoeal diseases, typhoid and viral hepatitis continue to be prevalent in India and have caused 10,738 deaths, over the last five years since 2017. Of this, acute diarrhoeal diseases caused maximum deaths followed by viral hepatitis, typhoid and cholera.
Uttar Pradesh has recorded the highest deaths due to diarrhoea followed by West Bengal, Assam, Odisha and Madhya Pradesh.
A large proportion of people do not have access to water within the house, increasing the chances of infections. Surface water sources are highly contaminated in India. Poor sewage disposal mechanisms lead to most of the sewage being drained into rivers and lakes that serve as reservoirs of microbial contamination.
Open defecation is common and the untreated sewage and effluents that are released into the water and soil are laden with various disease-producing bacteria. Poor access to safe water sources and toilets and poor WASH practices lead to high instances of waterborne diseases in the country.
Will climate change increase the incidence of waterborne diseases?
Climate change is predicted to increase the severity of weather-related events such as floods and droughts. India too will be greatly affected by these changes. For example, heavy rains and resultant floods can create conducive environments for numerous waterborne diseases such as diarrhoea, cholera, dysentery, typhoid and other bacterial and viral diseases. Evidence shows that rising temperatures and warmer climates can trigger an increased frequency of waterborne diseases such as cholera, giardiasis, salmonellosis, and cryptosporidiosis. Droughts can also trigger waterborne diseases due to increasing water shortages compromising sanitation and hygiene.
Read more here
What are the quality standards for safe drinking water?
Water is considered ‘safe’ when it is free from pathogenic agents and harmful chemicals, is pleasant to taste and usable for domestic purposes. Good quality water is that which can be safely used for various purposes such as household use, drinking, irrigation, industry, bathing etc.
The World Health Organisation (WHO) has developed international norms on water quality that are used for regulation and to set standards in developing and developed countries. These can be accessed here.
For India, these standards are set by the Bureau of Indian Standards (BIS) and the Indian Standards Institute (ISI). The Indian Standard DRINKING WATER–SPECIFICATION (Second Revision) can be accessed here
How can waterborne diseases be prevented?
While the role of government in improving access to safe water and sanitation is extremely important, a number of steps undertaken at the individual level can also go a long way in preventing diseases through increasing awareness and encouraging hygienic behaviours.
A number of waterborne diseases can be prevented by:
- Ensuring that water is from a safe source and undertaking water treatment measures in case of doubt
- Read more about water treatment methods here
- Know about water filters that you can use at home here
- Regular treatment of open water sources and testing water from open sources
- Find information on water testing facilities available in different states in India here
- Prevent drinking water from untreated sources
- Heating all food before consuming
- Washing hands thoroughly with soap and water before eating and after defecating
- Keeping food and water covered at all times
- Maintaining clean surroundings
- Encouraging the use of toilets through appropriate, user-friendly, hygienic toilet designs
Health policies and programmes directed at waterborne diseases
The National Health Policy 2017 reaffirms the government’s commitment to reforming the health sector and achieving universal health coverage. It focuses on disease elimination, reduction in mortality and improvement of health services.
The main strategy to control diseases caused by drinking of contaminated water is providing of safe drinking water. The Government of India supplements the efforts of the states by providing technical and financial assistance under the centrally-sponsored National Rural Drinking Water Programme (NRDWP) for providing safe and adequate drinking water supply facilities in rural areas of the country.
The National Centre for Disease Control (NCDC) provides assistance to state and Union Territory governments to prevent and control waterborne diseases and in investigating outbreaks of such diseases under the Integrated Disease Surveillance Programme (IDSP).
Read more here
While waterborne diseases continue to dominate the scene, the condition could worsen with climate change. Adequate preparedness both at the policy level and among citizens is the need of the hour.