Cholera: what is it, why does it occur, transmission and symptoms + Do we vaccinate?

Cholera: what is it, why does it occur, transmission and symptoms + Do we vaccinate?
Photo source: Getty images

Cholera is an intestinal infectious disease. It is caused by a bacterium. Although its treatment is simple, it is a threat to a person's health and life.


Cholera is an acute infectious disease affecting the intestinal tract. Its complications can threaten a person and his health. It is caused by the bacterium Vibrio cholerae.

It has a short incubation period, after which health problems set in rapidly. The most significant are diarrhoea and vomiting, followed by dehydration.

It is usually mild and sometimes asymptomatic. The severe form develops mainly in people at risk.

Two biotypes of these bacteria are known, namely Vibrio cholerae and Vibrio cholerae biotype eltor/Vibrio el Tor.

Who is at risk, you ask?

Cholera is not found in most developed countries.

In endemic areas, it is transmitted through contaminated/polluted water and food.

Severe disease and the highest mortality rates have been described in endemic areas among indigenous populations.

Infection in tourists is relatively rare and the course of the disease is not as severe and complicated. In most cases the disease is mild.

The important thing to remember in preventing cholera is to observe strict hygiene habits, not to drink contaminated water and not to eat undercooked food.

Before travelling to an area at risk, it is possible to be vaccinated. The vaccination also provides protection against other traveler's diarrhoea caused by strains of E. coli. It is taken by swallowing a solution through the mouth - orally (per os).

In addition to cholera, other infectious diseases are also transmitted by contaminated water, such as dysentery, hepatitis and typhoid fever.

What is cholera in a nutshell + some facts

Cholera is an acute disease of infectious origin.

It is caused by the bacterium Vibrio cholerae.

The incubation period from infection to the onset of symptoms is a few hours (approximately 12 hours) to 5 days.

It causes intestinal distress, which is potentially dangerous, especially in terms of dehydration, which occurs rapidly after severe diarrhoea and vomiting.

Most infected people will not have a severe course.

Cholera can be easily treated. But treatment must be started early.

In endemic areas, due to the poor socioeconomic situation, it causes a number of severe and fatal infections annually.

The WHO (World Health Organization) states that there are between 1.3 and 4 million infections and between 21 000 and 143 000 deaths from cholera each year.

The vaccine is recommended for people who travel to high-risk areas. In addition, it is important to think about observing hygiene measures.

It is reported that it is not dangerous for most people who do not live in areas affected by the disease. Still, there are a few facts to keep in mind.

Remember, cholera is:

  • an extremely virulent (contagious) disease
  • causes violent watery diarrhea and vomiting
  • very quickly causes dehydration
  • severe and complicated course can lead to death if the disease is left untreated
People's hands underwater
Lack of clean drinking water and sanitation as a major problem. Photo source: Getty Images


Cholera is caused by a toxigenic bacterium, Vibrio cholerae. There are several serogroups, two of which cause outbreaks, O1 and O139 - according to the WHO, there are no major differences between them. It is only the site of occurrence that matters.

Cholera causes endemic to epidemic outbreaks.

A person can become infected by ingesting contaminated water and food.

Sources also report that approximately 1 in 10 people will have a serious to life-threatening course.

Cholera bacteria Vibrio cholerae
Vibrio cholerae cholera bacteria. Source: Getty Images

The incubation period is...

...the period from infection to the onset of health problems =

= several hours to several days.

Approximately 12 to 72 hours is quoted.

But different sources describe a range of hours to 6 days.

How does one get infected?

Water and food are infected by the fecal-oral route, i.e. from the feces of an infected person and by failure to maintain hygiene. Literally through the mouth, digestive tract and feces into water, along with contamination in the food handling environment.

Cholera bacteria thrive in places where socio-economic standards are low, where drinking water is inadequately treated and where hygiene is not maintained.

Thus, a person drinks contaminated water or eats undercooked food with cholera bacteria.

Food, such as fruit and vegetables, is contaminated by untreated contaminated water (ice) when irrigated, washed or undercooked. Alternatively, soil that has been fertilised or irrigated with sewage and human excreta is contaminated.

It is reported that a person is unlikely to become infected through accidental contact with an infected person.

Route of transmission of cholera:

  1. Drinking contaminated water
  2. ingestion of food handled by an infected person
  3. eating food, especially shellfish, in at-risk areas that have been in contaminated water

Examples include cases from the USA where people became infected after eating inadequately prepared shellfish from the Gulf of Mexico.

The disease is most common in areas where there is no clean water supply and no sewage system, including parts of Africa and Asia, South America and the Caribbean.

How long is a person infectious?

Once infected, a person is infectious for the duration of the symptoms. Beware, infectivity persists for several weeks after the diarrhoea has subsided.

A person sheds cholera bacteria for several weeks after the diarrhea has subsided.

Can a person with the disease travel from abroad?

If a person becomes infected in the country of outbreak, he or she can of course come back home with the disease. And suspicion should be raised if there are health problems that include persistent diarrhea.

Spread can be expected especially in places with low standards of hygiene.

Even when scanty stools are present, the true causative agent of the health problems must be distinguished.

A person with symptoms should visit the designated outpatient clinic.
This is the infectious disease ward/clinic and the outpatient clinic for foreign and infectious diseases.
There, diagnosis, monitoring and treatment will take place, isolation is of course the norm.

How long does Vibrio cholerae survive?

In suitable conditions (= in water) for several years.

In food, up to 6 weeks.

The time increases with decreasing temperature.

Who is a patient at risk?

A patient at risk, a person with a higher susceptibility to cholera, is one who has a weakened immunity. This also includes people with reduced acidity of the gastric juices (when taking antacids - drugs to reduce acid production in the stomach) and with malnutrition. Subsequently, an elderly person with multiple long-term illnesses and young children can be considered at risk, especially in terms of possible dehydration during diarrhea and vomiting.

Children and the elderly are at risk of dehydration.
Why is dehydration dangerous in children? What are the symptoms?

Short stop in Vibrio cholerae bacteria

The bacteria multiply in the small intestine after entering the human body. They do not pass through the intestinal wall.

During their multiplication they produce a toxin dangerous to humans - an enterotoxin called cholera toxin.

This toxin is responsible for the increased excretion of water into the intestine.

Cholera toxin activates biochemical changes that lead to a decrease in sodium and chloride resorption. It stimulates the secretion of chloride and water into the intestines. It is a disorder of ion and water regulation and transport (the specific mechanism is complicated and unnecessary for a basic understanding of what the toxin causes).

The intestinal mucosa is intact and without signs of structural damage, even in the presence of severe diarrhoea and vomiting.

The most notorious cholera epidemics and pandemics

Several epidemics and pandemics have occurred in the past.

  • The first in 1816-1826 - in Asia, Bangladesh and the East Indies, China to the Caspian Sea
  • The second 1829-1851 in Europe and North America
  • The third 1852-1860 in Russia
  • Fourth 1863-1875 in Europe and Africa
  • Fifth 1881-1896 in Europe
  • Sixth 1899-1923 in Russia and the Ottoman Empire
  • Seventh 1961 - El Tor by subtype in more countries of the world, but with a mild course
  • Minor epidemics are reported from risk and endemic areas to this day, for example:
    • January 1991 to September 1994 in South America
    • after 2000, several outbreaks in Africa, India and other parts of the world
    • after 2010 in Haiti, also in Africa and other parts of the world
    • 2015 in Iraq
    • in 2022 Afghanistan, Bangladesh, Ethiopia, Nigeria, Ukraine

The rate of outbreaks increases wherever there is low socio-economic status, where hygiene standards cannot be maintained, where there is no supply of clean drinking water and where people live in inadequate living conditions. The reasons may be poverty, war or natural disasters.


Symptoms are typical of intestinal infectious diseases. The leading manifestation is diarrhea. Diarrhea/sparse stools are watery with the presence of mucus.

The main symptoms of cholera are:

  • persistent severe diarrhea - also referred to as watery stools
  • vomiting and nausea
  • thirst
  • muscle cramps in the legs
  • irritability and mental restlessness
  • dehydration - a risky complication that sets in very quickly
  • In children also fever or apathy and change in psyche

A person can lose up to 25 litres of fluid per day.

Diarrhoeal stools contain large numbers of cholera germs. These can cause transmission of infection after contact with water and food.

Therefore, it is necessary to think of strict hygiene and disinfection measures when caring for patients.

Cholera sicca = absent watery diarrhoea. Distention of the intestine and ileus (impaired function and patency of the intestines) are present.

Dehydration in cholera occurs very quickly. This is due to biochemical changes, the inability to absorb and, conversely, the excessive excretion of water in the human intestine.

Cholera bacteria on the surface of the small intestine - model representation, animation
The trouble is caused by bacteria and their toxins on the surface of the intestine. Source: Getty Images


Diagnosis is facilitated by the course of the disease. Rapid onset of complaints (persistent diarrhoea) with information present about visiting a risk area - i.e. a positive travel history.

A history of travel and diarrhoea is the basis of diagnosis.

The other type of diagnosis is of course the laboratory one. This involves microscopic and culture evidence in stool or blood tests for antibodies.

Gloved hand, holding a test tube, taking a water sample
The water sample can be used to test for pathogens. Source: Getty Images


The course of the disease cannot be clearly described.
As it ranges from asymptomatic to very severe with death as a consequence.

Often it is mild. Severe occurs in about one in 10 cases.
It depends on several factors that can affect it.

A severe and life-threatening course occurs mainly in indigenous populations in endemic areas.

Tourists are expected to have a milder course, sometimes even asymptomatic.

Of course, it is not possible to rely on this information.
It should be borne in mind that cholera is a highly infectious disease. It manifests itself in severe diarrhoea, which quickly leads to dehydration.

Course = onset of trouble after incubation period:

  • sometimes as the first vomiting, which may persist.
  • persistent diarrhoea - as a typical symptom
  • within hours of dehydration - which sets in most rapidly of the intestinal infectious diseases
  • cramps in the limbs

Sometimes vomiting is the first to set in. It is also typical that there is no abdominal cramping or urge to pass stools before diarrhoea.

Enterotoxin produced by the bacteria alters the function of intestinal cells and the mechanism controlling the absorption/excretion of water and electrolytes. This causes excessive water loss, up to over 1 litre per hour.

Cholera without treatment?

Excessive fluid loss leads to severe dehydration, renal impairment, cessation of urination, shock and even death.

During the day, the body loses up to 25 litres of fluid... A person loses up to a third of his body weight.

The key to avoiding complications is the presence of treatment. It should be early and timely.

How to avoid cholera while travelling?

The first place on the priority list is hygiene.

Do's and don'ts:

  • Wash your hands regularly - with soap and water, especially after using the toilet and before preparing and eating food.
  • drink only bottled water or tap water that has been boiled
  • use bottled or boiled water when brushing your teeth
  • do not eat undercooked or uncooked fruit and vegetables, including fresh salads that have not been washed with bottled or boiled water
  • do not eat shellfish and seafood
  • do not use ice from local water that has not been cooked or bottled
  • do not eat ice cream

What about vaccinations?

A vaccine can help prevent travel.

This is an orally administered solution. You drink a liquid that has 2 doses. There is a 1-6 week interval between doses.

The vaccine then provides protection for approximately 2 years.

Both doses must be taken at least 1 week before travel.

The vaccine can be given from the age of 2. From 2 to 6 years of age, 3 doses of the vaccine are given.

Although vaccination before travel is not compulsory, it is recommended. It depends on the place of travel.

Safety of the vaccine?
Rarely, problems such as mild nausea, abdominal cramps or rapid heartbeat may occur during vaccination. However, the symptoms quickly pass.

How it is treated: Cholera

Cholera treatment: easy and timely = fluids + antibiotics

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Video - Cholera - you can fight it too (WHO Eastern Mediterranean Region)

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