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Waterborne Diseases Factsheet

Water related diseases are classified into four types relating to the path of transmission:

  • Waterborne diseases, such as cholera and typhoid, are the diseases that are transmitted through drinking water. The interruption of transmission is achieved by proper treatment of drinking water.
     
  • Water-washed (water-scarce) diseases, such as polio, are diseases where the interruption of the transmission is achieved through proper attention to effective sanitation, washing and personal hygiene. Regular washing of hands, especially after going to the toilet, is the most effective measure in preventing many infections, as is proper washing and hygiene during food preparation, together with proper sanitation, waste disposal and fly control.
     
  • Water based diseases are diseases transmitted by contact with water, e.g. recreational swimming.
     
  • Water vector diseases, such as malaria, are diseases that are transmitted by a vector, such as the mosquito, which needs water or moisture in order to breed. Prevention of transmission is through a vector control.

Cholera – “Comma Bacterium"

Cholera is a diarrhoeal disease that is very sudden in onset. It is characterised by a massive loss of body fluids, through diarrhoea and vomiting, leading to severe dehydration, which can be fatal. The stool has the appearance of “rice water”. Infants and small children show the most rapid advance of the illness. Untreated cases of cholera can lead to death within 6 hours, depending on the degree of dehydration.

Microscope photo of the Vibrio cholerae "comma" bacterium
Microscope photo of the Vibrio cholerae "comma" bacterium

How is Cholera Transmitted?

Any person can contract the disease by ingesting water or food contaminated by a toxic strain of the bacterium called Vibrio cholera. This bacteria is excreted by infected individuals and can live for at least three weeks in saline (a solution of salt and water), warm and alkaline (pH higher than 7) water. The bacteria can also survive in food especially seafood.

How should the patient be treated?

Urgent and immediate replacement of the water and salts that are lost through diarrhoea and vomiting is the most effective treatment for cholera. Such treatment is dramatically life- saving.

Transmission route

Waterborne

Management option

Hygiene, sanitation and clean drinking water.

Preventative Measures

  • Never drink untreated water.
  • Water can be disinfected by adding 1 teaspoon of domestic bleach to 20 litres of water and leaving for at least three minutes (take care to avoid burns). Where water is cloudy, add 2 to 3 extra teaspoons of bleach.
  • Proper personal hygiene and sanitation infrastructure should be installed and maintained.
  • Clean drinking water containers should always be used. Recontamination of stored clean water should be avoided by not inserting the hands or dirty equipment when removing water from the container.

Interesting facts

  • A large number of people who drink contaminated water can become carriers with little or no symptoms at all. People who are carriers can continue to excrete the bacteria for a period of up to a few weeks.
  • Vaccination of individuals with the cholera vaccine can offer slight protection against the disease, but this will only last for six months, and does not prevent infection and therefore transmission of the disease.
  • After ingestion of the bacteria it takes two to four days before cholera symptoms may show.
  • Antibiotics may help by shortening the duration of diarrhea.
  • Rapid dehydration can only be treated by re-hydration through oral and/or intravenous fluids.
  • Not all Vibrio cholera organisms are harmful. Non toxic strains of the bacteria also occur naturally.

Gastroenteritis – "Stomach Bug" 

What is Gastroenteritis?

Gastroenteritis is a disease where there is a sudden onset of vomiting and watery diarrhoea often accompanied by moderate fever and sometimes stomach cramps. The incubation period is generally short (8 to 48 hours). The disease is sometimes referred to as "gastric flu" or "stomach bug". Gastroenteritis can be caused by a wide variety of microorganisms.

Healthy adults usually recover within a few days, but the disease can be life threatening in case of infants, the elderly and individuals in the advanced stages of HIV infection.

Untreated gastroenteritis in infants can rapidly lead to death by dehydration

How is Gastroenteritis transmitted?

Transmission of the disease can occur by a variety of routes, such as eating contaminated food or drinking contaminated water. Very rapid spread within families or groups of people sharing the same utensils, or living together is common, especially with the viral forms of the disease, as it is spread via the faecal oral route with poor hygiene.

The microorganisms causing gastroenteritis can survive freezing. Ice blocks made from contaminated water can be a significant route of infection.

How should the patient be treated?

Urgent and immediate replacement of the water and salts that are lost, especially in infants and elderly, is of critical importance. Antibiotics are not recommended as a routine measure, except in very young infants, some elderly persons, or in the presence of fever or bloody stools.

In emergencies, sports drinks containing isotonic fluids can be used to replace the necessary fluids. A weak solution of salt and sugar can also be used (get details from your local clinics)

Transmission route

Gastroenteritis is predominantly a water washed disease but may also be waterborne.

Management option

Clean drinking water, effective sanitation and good hygiene.

Preventative measures

  • Never drink untreated water.
  • Water can be disinfected by one teaspoon of domestic bleach to 20 litres of water and leaving it for one hour before drinking. If no bleach is available the water can be boiled vigorously for at least five minutes and kept simmering for at least another 15 minutes (take care to avoid burns). If the water is cloudy, add 2 to 3 extra teaspoons of bleach.
  • Proper personal hygiene and sanitation infrastructure should be installed and maintained.
  • Clean drinking water containers should always be used.

Interesting facts

  • Carriers showing no symptoms can occur. Thus the importance of proper personal hygiene, washing your hands after going to the toilet, and the proper cleaning of soiled clothes with hot water.
  • Vaccination is not possible as there are so many microorganisms that can cause Gastroenteritis.
  • Gastroenteritis can be life threatening in the case of an individual with advanced HIV infection, thus extra vigilance to ensure clean drinking water and food is essential for such patients.
  • Adequate sanitation, treatment of wastes and fly control is an added precaution.

 

Typhoid Fever 

What is typhoid fever?

Typhoid fever is caused by Salmonella typhi. Following infection, after an incubation period of 1 to 3 weeks, the patient has a gradual onset of illness, starting with a headache, followed by fever and abdominal pain. Constipation is more common than diarrhoea in the early stages of the illness. Later bronchitis develops. The infection can last up to 3 weeks or even longer. In some individuals infection may occur with no signs of illness at all.

In some recovered cases, a chronic carrier state develops, which may persist lifelong. Such typhoid carriers should not be allowed to prepare food for others, or work in day- care centres, as they present a continual source of the organisms in their stools. They should be treated with antibiotics until three consecutive stools are negative for Salmonella typhi.

Salmonella typhi
Salmonella typhi

How is typhoid transmitted?

Typhoid bacilli are excreted in the stools of infected individuals, and continue to be excreted by untreated patients after recovery for up to 4 months. The disease is transmitted via the faecal-oral route, either via drinking water or food. Flies may also play a role as a passive vector leading to food contamination.

How should the patient be treated?

The use of antibiotics at the early stage of infection is essential to prevent the appearance of life-threatening complications, and bed rest is essential. A loss of appetite and weight loss are characteristics of the diseases. The consequences of typhoid can be very severe in the case of HIV positive individuals.

Transmission route

Typhoid fever is predominantly a water-washed disease, but may also be waterborne.

Management option

Hygiene, sanitation and clean drinking water

Preventative measures

  • Don't drink untreated water.
  • Water can be disinfected by adding one teaspoon of domestic bleach to 20 litres of water and leaving it for one hour before drinking, or if no bleach is available the water can be boiled vigorously for at least five minutes and kept simmering for at least another 15 minutes (take care to avoid burns). If the water is cloudy, add 2 to 3 extra teaspoon of bleach
  • Proper personal hygiene and sanitation infrastructure should be installed and maintained.
  • Wash and peel fruit and vegetables before eating.
  • Wash your hands after going to the toilet and before preparing food.

A common source of infection is contaminated water or food from street vendors
A common source of infection is contaminated water or food from street vendors

Interesting facts

  • The typhoid bacillus only lives in humans, and apparently healthy carriers are usually the source of new outbreaks.
  • Infections can be acquired from ice cubes prepared from contaminated water


Campylobacteriosis (Campy)  

What is "Campy"?

Campylobacteriosis is a diarrhoeal disease of the gut, caused by the bacterium Campylobactor jejuni. It is characterised by slight to severe diarrhoea, which may be bloody (dysenteric), together with abdominal cramps, fever and, in severe cases vomiting and convulsions. Some infections may be very mild, or no symptoms at all.

Drawing of Campylobacter cell with flagella
Drawing of Campylobacter cell with flagella

How is "Campy" transmitted?

Transmission is predominantly via the faecal-oral route. Animals, especially poultry and cattle, are an important reservoir of the bacterium. Good hygiene and cleanliness when preparing poultry for cooking is essential to prevent accidental contamination of other foods and drinks.

How should the patient be treated?

The basis of treatment is fluid and salt replacement. If the infection is severe, specific antibiotics may be used to shorten the period of infection. Recovery can be prolonged in the case of individuals in the advance stage of HIV infection.

Transmission route

Waterborne

Management option

Hygiene, sanitation and clean drinking water

Preventive measures

  • Practice good personal hygiene.
  • Never eat uncooked poultry.
  • Always clean the cooking board and knives with soap and hot water after cutting up poultry.
  • Wash hands thoroughly with soap and water after handling pets and before eating food.
  • Always wash hands after changing baby’s nappies.
  • Do not drink untreated water.
  • Water can be disinfected by adding one teaspoon of domestic bleach to 20 litres of water, allowing it to stand for 1 hour before drinking. If water is cloudy (turbid) add 2 to 3 extra teaspoons of bleach.

Interesting facts

  • Milk may on occasion be a source of infection, therefore, do not drink unpasteurised milk.
  • If a microwave is used for cooking chicken, make sure that the chicken is well cooked, or it may be a source of infection.
  • Infants and elderly, together with immuno-compromised people are most susceptible to the disease.


Amoebic Dysentery 

What is amoebic dysentery?

Amoebic dysentery is a diarrheal disease caused by the parasite Entamoeba histolytica. As much as 90% of infections with this parasite are without symptoms. Where symptoms occur, these appear between three days to three months of infection. The diarrhoea, when it occurs, is often bloody, and associated with tenderness in the abdomen, nausea and weight loss. Life threatening complications can occur, such as intestinal perforation.

How is amoebic dysentery transmitted?

The disease is transmitted via the faecal-oral route, the organism being excreted in the stool of an infected individual. A new infection is contracted when contaminated drinking water or food is consumed. Person to person contact also occurs, especially where hygiene is poor, but is uncommon. Common sources of infection are raw fruit or vegetables that have been irrigated with contaminated water.

How should the patient be treated?

Symptomatic cases of the disease require treatment with specific antiparasitic medication. Where complications have occurred, surgical intervention may be necessary.

Transmission route

Primarily it is a water washed disease, but may also be spread as a waterborne disease and by sexual contact.

Management options

Hygiene, sanitation and clean drinking water.

Prevention

  • Always wash fruit and vegetables, especially lettuce, well with clean water before eating.
  • Practice strict hygiene after going to the toilet and before preparing food.
  • Do not drink contaminated water.
  • Water can be disinfected by adding one teaspoon of domestic bleach to 20 litres of water, allowing it to stand for 1 hour before drinking. If water is cloudy (turbid) add 2 to 3 extra teaspoons of bleach.

Interesting facts

  • 90% of cases are without any symptoms, but these can be a source of infection for others, and illustrates the importance of sound sanitation practices to avoid contamination of water resources at all times.
  • Vegetables eaten raw should not be irrigated with water contaminated with the parasite.
  • Individuals infected with HIV are likely to be more seriously ill when infected with the organism.

Cryptosporidiosis ("Crypto")

What is Cryptosporidiosis?

Crptosporidiosis, often abbreviated as “Crypto”, is the infection of the gut caused by the parasite Cryptosporidium parvum. From 1 to 12 days after infection there is an onset of water diarrhoea and stomach pains. Sometimes vomiting and slight fever may occur. Recovery takes place after one to two weeks in healthy people, but in individuals with advanced HIV infection, recovery is delayed, and the disease can be life threatening.

How is "crypto" spread?

Infection takes place when the parasite is ingested. Person to person contact may also spread the disease, especially where there is poor personal hygiene. Animals often serve as a reservoir for the parasite, which may be present in their faeces.

The parasite is generally not destroyed by chlorination, and effective filtration is essential to remove the parasite from the water. Boiling for one minute does not inactivate the parasite.

How should the patient be treated?

Destruction of the parasite with a drug is difficult and treatment is largely symptomatic, to ensure that prolonged diarrhoea does not lead to a loss of fluids and salts. Antidiarrhoeal drugs may help, together with rehydration therapy. The infection is usually self-limited in immuno-competent persons.

Transmission routes

Both a waterborne disease and water washed disease.

Management option

Clean drinking water, sanitation and hygiene.

Preventive measures

  • If the drinking water has not been filtered very effectively (through an extremely small pore size filter), then it is necessary to boil the water for at least one minute.
  • Adding bleach to water does not make it safe for “crypto”, unless accompanied by very intense UV light. Small, low power UV lamps are unsuitable in this regard.
  • Very fine filters (0.1 to 1.0 micrometre) may remove the parasite and make the water safe.
  • Boiling the water is the best way to make it safe.
  • Good personal hygiene and effective sanitation are critical.

Interesting facts

  • Persons with advanced HIV disease should take extra precautions to avoid infection, such as boiling drinking water, especially if the drinking water treatment supply is suspect.
  • As reinfection may occur, practice good personal hygiene, especially after going to the toilet.
  • Persons with weakened immune systems should always wash fruit and vegetables well with clean or boiled water, and should avoid touching farm animals, especially calves and lambs.

Giardiasis 

What is giardiasis?

Giardia parasiteGiardiasis is the infection of the gut by the parasite Giardia lamblia. It is usually a mild diarrhoeal disease. "Stomach" cramps and loose creasy stools accompany it.

In some people no signs of the disease occur at all. The diarrhoea may result in associated weight loss.

How is Giardiasis transmitted?

People infected with Giardia in their faeces excrete the parasite. It may also be found in animal excreta. Infection occurs through contamination of drinking water as a result of inadequate sanitation, through person to person spread by poor hygiene, or through contamination of drinking water containers or food.

How should the patient be treated?

Giardiasis is easily treatable with prescription medicines effective against the parasite; however, in otherwise healthy individuals recovery is usually rapid. HIV infected persons usually require medical treatment.

Transmission routes

Water-washed and waterborne.

Management option

Clean drinking water and effective hygiene and sanitation.

Prevention

  • Through hand washing with soap and water, especially after changing baby’s nappies, and after using the toilet.
  • Wash your hands with soap and water before preparing food.
  • If drinking water is a suspect, then boil it for five minutes.
  • Sub micron filters will also remove Giardia cysts from water.

Interesting facts

  • The disease is normally diagnosed from a stool sample.
  • Food handlers should be booked off work if they become infected, and avoid preparing food until they are clear of the infection.
  • A common source of infection is in child day care centres, where one infant with Giadiasis may readily transmit the disease to others.

Shigellosis (Shigella Dysentery)

What is Shigellosis?

Shigella dysentery, and other Shigella species cause shigellosis. The symptoms are a sudden onset of abdominal pain, cramps and diarrhoea. There is often mucus and blood in the stools and a fever is common. Dehydration may occur in severe cases, with decreased urine production, which may progress to kidney failure if the dehydration is untreated. The infection is most common in young children of pre-school age, although people of all ages can be affected. Symptoms usually last for a few days to a week, but can last longer. Asymptomatic infections also occur, where apparently well people can be a source of infection for a few weeks.

How is Shigellosis transmitted?

Shigellosis can be spread by close person-to-person contact, as well as on occasions by contaminated food or water, via the faecal-oral route. Scrupulous cleaning of hands after using the toilet, changing nappies, or prior to preparing or eating foods needs to be practiced to prevent transmission, especially if a person is infected with the organism and is excreting the bacterium in the stool.

How is the patient treated?

Rehydration with fluids is necessary to prevent dehydration. In rare cases, with kidney failure or severe rectal bleeding, hospitalisation is required. Antibiotics are normally administered to shorten the duration of the infection and to hasten recovery. The diagnosis is confirmed through the culture of stool samples. Day care workers and food handlers should be especially careful not to return to work until two consecutive stool samples are negative for shigella.

Transmission route

Water-washed, and waterborne.

Management options

Hygiene, sanitation, and clean drinking water.

Prevention

  • Always wash your hands with soap and water after going to the toilet, changing nappies, or before preparing food.
  • Untreated water should not be drunk.
  • Water can be disinfected by adding 1 teaspoon of domestic bleach to 20 litres of water and leaving it for 1 hour before drinking, or if no bleach is available, the water can be boiled for at least 5 minutes. If the water is cloudy add 2 to 3 extra teaspoons of bleach.
  • Adequate sanitation and fly control, as well as provision of clean, disinfected drinking water.
  • Clean drinking water containers should always be used.

Interesting Facts

  • Recovery from shigellosis is in most cases spontaneous, except in the very young and very old, where life-threatening dehydration and other complications can occur. Special care needs to be taken by food handlers with thorough hand washing.

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