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Cholera

Category: Illness or disabilities

Type

Involuntary

Introduction and description

 

Cholera is an infection of the small intestine by some strains of the bacterium Vibrio cholerae.  A much fuller description of this bacteria with its various strains and life cycle are provided in the section on Vibrio cholera infection.

Cholera affected an estimated 3–5 million people worldwide and caused 58,000 –130,000 deaths a year in 2010. While it is currently classified as a pandemic, it is rare in the developed world. Children are mostly affected.  Cholera occurs as both outbreaks and chronically in certain areas.

Areas with an ongoing risk of disease include Africa and south-east Asia. While the risk of death among those affected is usually less than 5%, it may be as high as 50% among some groups who do not have access to treatment.

Seven cholera pandemics have occurred in the past 200 years, with the seventh pandemic originating in Indonesia in 1961.  In Russia alone, between 1847 and 1851, more than one million people perished of the disease.  Between 1900 and 1920, perhaps eight million people died of cholera in India.  The final pandemic originated in 1961 in Indonesia and is marked by the emergence of a new strain, nicknamed El Tor, which still persists today in developing countries.

The Haiti cholera outbreak was the worst epidemic of cholera in recent history, according to the U.S. Centers for Disease Control and Prevention. After the 2010 earthquake, in a little over two years, it killed at least 7,000 Haitians and sickened a few hundred thousand more while spreading to neighbouring countries including the Dominican Republic and Cuba.  By August 2015, after the rainy season that year brought a spike in cases, more than 700,000 Haitians had become ill with cholera and the death toll had climbed to 9,000.

V. cholerae was first isolated as the cause of cholera by Italian anatomist Filippo Pacini in 1854, but his discovery was not widely known until Robert Koch, working independently 30 years later, publicized the knowledge and John Snow, in England, identified the importance of contaminated water as its cause in 1854.  Historical descriptions of cholera are found as early as the 5th century BC in Sanskrit.

Symptoms

 

When ingested, V. cholerae can cause symptoms in a host within several hours to 2–3 days of ingestion. In endemic areas, 75% of cases are asymptomatic, 20% are mild to moderate, and 2-5% are severe forms such as cholera gravis.

  • Diarrhoea and vomiting  - When ingested, V. cholerae causes severe diarrhoea and occasionally vomiting.  V. cholerae  results in a profuse, watery diarrhoea (known as "rice-water stool" - a grey and cloudy liquid),  and abdominal cramps.  It is worth noting that this is a protective measure on the part of our bodies, our immune system is desperately trying to flush out the bacteria, as there is a more serious danger that it could colonise the small intestine. It is worth emphasising this very important point, as the last thing one should do is to stop the diarrhoea, the intestines are acting as a part of the immune system and using water as a flushing mechanism.  The danger comes if there is not enough water to keep the flushing process going, or the intestine loses the battle and the bacteria enters the blood stream – then we are in trouble
  • Dehydration– unless adequate fluids are taken on a very regular basis, dehydration will result. The person will experience thirst, dry mucous membranes, decreased skin turgor [skin elasticity], a hoarse voice and sunken eyes.  There may be Oliguria or hypouresis (both names from roots meaning "not enough urine") - a low output of urine.  If the body does not have enough water the flushing mechanism needed to get rid of the bacteria will be slowed or stopped, at which point the bacteria is free to enter the body.  Any symptoms that follow are a result of the bacteria reaching other parts of the body
  • Circulatory problems – circulatory problems may be caused by the dehydration, but may also be a result of the bacteria travelling round the blood stream, resulting in hypotension, weak or absent radial pulse, tachycardia, and tachypnea
  • Kidney failure – the kidneys may be overwhelmed by the bacteria and lack of water and essential minerals
  • Brain damage – the bacteria [toxins and phages] has reached the brain, resulting in seizures, somnolence, coma, and death.  Dehydration can also have similar effects.

If inadequate amounts of fluids are not given to continue the flushing process, death can occur in a few hours to days in untreated children. The disease is also particularly dangerous for pregnant women and their fetuses during late pregnancy, as the bacteria may attack the baby causing premature labour and fetal death. If the person becomes severely dehydrated, allowing the bacteria to enter the blood stream, up to 60% of patients can die;  however, less than 1% of cases treated with rehydration therapy are fatal. The disease typically lasts 4–6 days.

Causes

 

Cholera is an infection of the small intestine by some strains of the bacterium Vibrio cholerae.  The cause is thus this bacteria, but where does this bacteria come from? 

Unless we know the sources it is not possible to prevent the disease.  The main reservoirs of V. cholerae are aquatic sources such as brackish water and estuaries, often in association with copepods or other zooplankton, shellfish, and aquatic plants.

Infected people - Transmission from person to person, even to health care workers during epidemics, is rarely documented.  BUT the source of contamination of water supplies, food and so on is nearly always other cholera sufferers when their untreated diarrheal discharge is allowed to get into waterways, groundwater or drinking water supplies.

Polluted drinking water - Cholera infections are most commonly acquired from drinking water in which V. cholerae is found naturally or into which it has been introduced from the faeces of an infected person. V. cholerae thrives in an aquatic environment, particularly in surface water. The primary connection between humans and pathogenic strains is through water, particularly in economically impoverished areas that do not have good water purification systems. In effect, one of the obvious preventative methods is to provide a source of unpolluted clean drinking water and proper sanitation systems, well away from the drinking water.

Contaminated food - Other common vehicles include contaminated fish and shellfish, produce, or leftover cooked grains that have not been properly reheated. Cholera has been found in both shellfish and plankton.  If people harvest seafood such as oysters, for example, in waters infected with sewage, the Vibrio cholerae accumulates in zooplankton and the oysters eat the zooplankton.  Thus there is a chain of infection.

Pharmaceuticals – The source we have used for this finding is the eHealthme site, which collects the Adverse Drug Reports submitted by doctors in the USA to the FDA and SEDA.  The fact it is the USA only makes the finding that much more alarming, as it shows that by using pharmaceuticals that suppress the immune system, people in the USA have caught cholera.

Source eHealthme:  Could your drug case Cholera?

Drug

Number of Cholera reports

Cisplatin

8

chemotherapy

Enbrel

2

immunosuppressant

Humira

2

immunosuppressant

Ondansetron

7

anti-emetic

Another cause is the use of antacids and proton pump inhibitors.  About 100 million bacteria must typically be ingested to cause cholera in a normal healthy adult. This dose, however, is less in those with lowered gastric acidity (for instance those using proton pump inhibitors).  The acid normally kills these bacteria.

Preventative Measures

 

The obvious preventative methods are to provide a source of unpolluted clean drinking water and proper sanitation systems, well away from the drinking water. 

Cholera has caused some interesting political discussions about where responsibility should lie for clean water:

Water privatization programs in South Africa, part of a government policy aimed at making people pay for the full cost of running water ("total cost recovery"), was developed by private water companies and the World Bank to finance improved water supplies and build the country's economy. Instead the programs are causing more misery than development. Millions of poor people have had their water supply cut off because of inability to pay, forcing them to get their water from polluted rivers and lakes and leading to South Africa's worst cholera outbreak--which the government paid millions of dollars to control. Residents in some townships are rebelling, and many of the private multinational water companies are reassessing their involvement in South Africa.  PMID:  14758861

To provide a balance to this view, release of the provision of water supply and sewerage treatment in the UK from government control, resulted in cleaner beaches, replacement of old leaking pipes,  the building of a large number of new treatment plants and repair of many crumbling dams.

So the answer is not straightforward.  On the other hand it is THE KEY issue for health for all developing countries and not a few so called developed countries.  Clean water and adequate sanitation systems ought to be our number one priority in improving health.

Treatment

Rehydration, rehydration, rehydration.  Constant rehydration with pathogen free water and enough minerals to ensure mineral balance is maintained.  Thus electrolyte rebalancing fluids.  An untreated person with cholera may produce 10 to 20 litres (3 to 5 US gal) of diarrhoea a day, thus this amount of fluid is needed to replace the fluids lost.

Remember that to get rid of the pathogen, you must leave the body to flush it out.

And sleep.

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