Cholera

Cholera is a severe diarrhoeal disease caused by infection with the bacterium Vibrio cholerae. The route of transmission is primarily the consumption of drinking water contaminated with faeces, but in rare cases the infection can also be passed on directly from person to person. The incubation period ranges from a few hours to up to five days.

Cholera is particularly endemic in areas with high population density and poor drinking water and sewage supply. These factors are particularly true for areas in South America, Africa and Southeast Asia. Cases in Europe are mostly the result of the cholera bacterium being carried over from these regions.

In up to 85% of all cholera infections there are no symptoms at all (called silent infection), but when the disease breaks out the mortality rate is between 20 and 70% if left untreated. An infection with cholera is subject to quarantine - adequate treatment can therefore only be carried out in hospitals with special infection departments.

Cholera is caused by an infection with the bacterium Vibrio cholerae, which is mostly transmitted via drinking water contaminated with faeces, less frequently via contaminated food. Direct transmission from person to person is also possible, but is a very rare occurrence.

The outbreak of cholera only occurs when a very large number of cholera bacteria manage to enter the gastrointestinal tract. The bacteria pass through the stomach and then multiply mainly in the small intestine, where they attach themselves to the intestinal cells and release a toxin (cholera toxin). This causes a severe loss of water and electrolytes from the intestinal mucosa.

Since cholera bacteria are killed by stomach acid, consumption of only mildly contaminated drinking water usually does not cause illness. This does mean, however, that the risk of infection increases when stomach acid production is reduced (for example, by hydrochloric acid inhibiting medication - "stomach protection"). Also, only small numbers of germs are usually eliminated without problems by the immune system before the disease breaks out. A poor state of health, for example caused by malnutrition or AIDS, favours a cholera infection.

In some people, a silent infection occurs. This is characterised by the fact that the infected person does not suffer from any symptoms, but he/she permanently excretes cholera bacteria with the stool and thus indirectly infects other people.

If the cholera bacteria succeed in settling in the mucous membrane of the small intestine, multiplying and releasing the cholera toxin, the typical symptoms of cholera occur, such as sudden onset of severe abdominal pain, vomiting and rice-water-like diarrhoea with high fluid loss (rice-water-like because of the milky-white mucus flakes in the stool).

Due to the severe diarrhea and vomiting, the body loses large amounts of fluid (up to 20 liters per day) and electrolytes (mineral salts such as sodium, potassium). This leads to a severe lack of fluids - called the stage of exsiccosis - with associated symptoms such as hypothermia and a noticeable facial expression with sunken cheeks and standing skin folds. The great loss of water and electrolytes leads to hoarseness and, mostly in the calf, to muscle cramps and impaired consciousness. Finally, kidney failure and death from circulatory failure may occur.

In the acute course of a cholera infection, a reliable diagnosis can be made by microscopic detection of the cholera bacterium Vibrio cholerae in the stool. Normally, in the case of a cholera infection, the stool consists almost exclusively of water and vibrions; by means of a culture, the pathogens can also be detected in low concentrations and in samples of vomit or intestinal secretions.

However, a reliable diagnosis of cholera is not necessary for therapy - the main thing is to treat the diarrhoeal disease as quickly as possible. In the early stages, cholera is easily confused with other diarrhoeal diseases such as salmonellosis, shigellosis or food poisoning.

In the therapy of cholera, sufficient fluid intake should be ensured immediately to compensate for the severe fluid loss caused by diarrhoea. In addition, sufficient electrolytes and glucose (sugar) are administered as a drinking or infusion solution to also absorb the electrolyte loss. Antibiotic therapy can shorten the course of the disease, and with timely fluid and electrolyte replacement, the prognosis for cholera is good.

The affected person should be hospitalized immediately, but if this is not possible, give him/her a highly sweetened as well as salty liquid - this can be easily prepared yourself by dissolving several teaspoons of sugar and a level teaspoon of salt in a liter of water.

Only the intake of preparations against diarrhoea without therapy of the loss of fluids and electrolytes is not advisable in the case of cholera.

Cholera is easily treatable if treatment is started in time, and complications are relatively rare. If left untreated, however, the infection is very dangerous and in up to 70% of cases is fatal due to the severe loss of water and electrolytes. As a result, cholera epidemics in developing countries usually have devastating consequences, as poor hygienic conditions and malnutrition are often compounded by poor medical care, which is unable to provide the relatively simple treatment for those affected.

Cholera is rare in industrialized countries - if illnesses occur, the pathogen was usually brought in by long-distance travel.

Once the disease has been overcome, there is only limited immunity to a new infection with cholera.

To prevent cholera infection, it is primarily recommended to maintain good hygiene standards for food and drinking water. In endangered areas, only boiled drinking water should be consumed and, if possible, uncooked food should be avoided.

Vaccination against cholera is also possible and can reduce the risk of contracting the disease. The former intramuscular vaccination is considered outdated and ineffective, newer oral vaccinations have proven to be more tolerable and additionally offer some protection against the classic traveler's diarrhea.

If cholera nevertheless occurs, the affected person must be treated as quickly as possible. To reduce the risk of further infections, strict hygiene must be maintained. If possible, patients should be treated in isolation during the acute phase of cholera.

Once an infection has been overcome, immunity is only temporary - multiple infections are quite possible during longer stays in epidemic areas.