Water Born Diseases

General Information

Water-borne diseases are any illness caused by drinking water contaminated by human or animal faeces, which contain pathogenic microorganisms.

The full picture of water-associated diseases is complex for a number of reasons. Over the past decades, the picture of water-related human health issues has become increasingly comprehensive, with the emergence of new water-related infection diseases and the re-emergence of ones already known. Data are available for some water-, sanitation- and hygiene-related diseases (which include salmonellosis, cholera, shigellosis), but for others such malaria, schistosomiasis or the most modern infections such legionellosis or SARS CoV the analyses remain to be done.

The burden of several disease groups can only partly be attributed to water determinants. Even where water plays an essential role in the ecology of diseases, it may be hard to pinpoint the relative importance of aquatic components of the local ecosystems
 

Transmission

Water borne diseases spread by contamination of drinking water systems with the urine and faeces of infected animal or people.

This is likely to occur where public and private drinking water systems get their water from surface waters (rain, creeks, rivers, lakes etc.), which can be contaminated by infected animals or people. Runoff from landfills, septic fields, sewer pipes, residential or industrial developments can also sometimes contaminate surface water.

This has been the cause of many dramatic outbreaks of faecal-oral diseases such as cholera and typhoid. However, there are many other ways in which faecal material can reach the mouth, for instance on the hands or on contaminated food. In general, contaminated food is the single most common way in which people become infected.

The germs in the faeces can cause the diseases by even slight contact and transfer. This contamination may occur due to floodwaters, water runoff from landfills, septic fields, and sewer pipes.

The following picture shows the faecal-oral routes of diseases transmission.

The only way to break the continued transmission is to improve the people’s hygienic behaviour and to provide them with certain basic needs: drinking water, washing and bathing facilities and sanitation. Malaria transmission is facilitated when large numbers of people sleep outdoors during hot weather, or sleep in houses that have no protection against invading mosquitoes. Malaria mosquitoes, tropical black flies, and bilharzias snails can all be controlled with efficient drainage because they all depend on water to complete their life cycles.

Clean water is a pre-requisite for reducing the spread of water-borne diseases. It is well recognized that the prevalence of water-borne diseases can be greatly reduced by provision of clean drinking water and safe disposal of faeces.

Water is disinfected to kill any pathogens that may be present in the water supply and to prevent them from growing again in the distribution systems. Disinfection is then used to prevent the growth of pathogenic organisms and to protect public health and the choice of the disinfect depends upon the individual water quality and water supply system.

Without disinfection, the risk from waterborne disease is increased.

The two most common methods to kill microorganisms in the water supply are: oxidation with chemicals such as chlorine, chlorine dioxide or ozone, and irradiation with Ultra-Violet (UV) radiation.

Common Diseases

  • Listeria

A listeria infection (listeriosis) is a relatively uncommon food-borne illness. The bacteria that cause listeria infections (Listeria monocytogenes) are found in soil and water. Many wild and domestic animals also carry the bacteria. Listeria has the unusual ability to grow in cold environments, including certain refrigerated or frozen foods.

Most otherwise healthy people exposed to listeria don't become ill. However, a listeria infection can be devastating for pregnant women and people who have weak immune systems. Listeria infections cause about 500 deaths a year in the United States, according to the Centers for Disease Control and Prevention (CDC).

Prompt antibiotic treatment can help curb the effects of a listeria infection. Prevention is key, however, starting with simple food-safety precautions.

  • E. coli

E. coli is the name of a germ, or bacterium, that lives in the digestive tracts of humans and animals.

There are many types of E. coli, and most of them are harmless. But some can cause bloody diarrhea. The most common type is called E. coli O157:H7. In some people, this type of E. coli may also cause serious blood problems or kidney failure, which can lead to death.

Other strains of E. coli can cause urinary tract infections or other infections.

What causes an E. coli infection?

You get an E. coli infection by coming into contact with the feces, or stool, of humans or animals. This can happen when you drink water or eat food that has been contaminated by feces.

E. coli in food

E. coli can get into meat during processing. If the infected meat is not cooked to 160°F (71°C), the bacteria can survive and infect you when you eat the meat. This is the most common way people in the United States become infected with E. coli. Any food that has been in contact with raw meat can also become infected.

Other foods that can be infected with E. coli include:

  • Raw milk or dairy products. Bacteria can spread from a cow's udders to its milk. Check the labels on dairy products to make sure they contain the word "pasteurized." This means the food has been heated to destroy bacteria.
  • Raw fruits and vegetables, such as lettuce, alfalfa sprouts, or unpasteurized apple cider or other unpasteurized juices that have come in contact with infected animal feces.

E. coli in water

Human or animal feces infected with E. coli sometimes get into lakes, pools, and water supplies. People can become infected when a contaminated city or town water supply has not been properly treated with chlorine or when people accidentally swallow contaminated water while swimming in a lake, pool, or irrigation canal.

What are the symptoms?

Bloody diarrhea is the main symptom of an E. coli infection. You may also have stomach cramps and nausea and vomiting. Some people do not notice any symptoms. Children are more likely than adults to have symptoms. Symptoms usually start 3 or 4 days after you come in contact with the E. coli germ.

Most people get better in about a week. They often don't see a doctor and don't know that E. coli caused their problems.

  • Diarrhea

Diarrhea occurs world-wide and causes 4% of all deaths and 5% of health loss to disability. It is most commonly caused by gastrointestinal infections which kill around 2.2 million people globally each year, mostly children in developing countries. The use of water in hygiene is an important preventive measure but contaminated water is also an important cause of diarrhea. Cholera and dysentery cause severe, sometimes life threatening forms of diarrhea.

The cause

Diarrhea is a symptom of infection caused by a host of bacterial, viral and parasitic organisms most of which can be spread by contaminated water. It is more common when there is a shortage of clean water for drinking, cooking and cleaning and basic hygiene is important in prevention.
Water contaminated with human faeces for example from municipal sewage, septic tanks and latrines is of special concern. Animal faeces also contain microorganisms that can cause diarrhea.

Diarrhea can also spread from person to person, aggravated by poor personal hygiene. Food is another major cause of diarrhea when it is prepared or stored in unhygienic conditions. Water can contaminate food during irrigation, and fish and seafood from polluted water may also contribute to the disease.

The infectious agents that cause diarrhea are present or are sporadically introduced throughout the world. Diarrhea is a rare occurrence for most people who live in developed countries where sanitation is widely available, access to safe water is high and personal and domestic hygiene is relatively good. World-wide around 1.1 billion people lack access to improved water sources and 2.4 billion have no basic sanitation. Diarrhea due to infection is widespread throughout the developing world. In Southeast Asia and Africa, diarrhea is responsible for as much as 8.5% and 7.7% of all deaths respectively.

OTHER WATER RELATED DISEASES


1. Anaemia

2.Campylobacteriosis

3.Hepatitis

4. Hookworm Infection

5. Malnutrition

6.Onchocerciasis

7.  polio

8. Scabies

9. Trachoma

10. Typhoid