What are the symptoms of cholera?

Early signs of cholera include:

  • rapid heart rate
  • feeling irritable or restless
  • sunken eyes
  • loss of skin elasticity
  • dry mouth and tongue
  • feeling thirsty
  • low blood pressure
  • muscle cramps

The main symptoms of cholera are:

Diarrhoea – the main symptom of cholera is a sudden onset of watery diarrhoea, which can cause an extreme loss of fluid in a very short period of time. Left untreated, someone infected with cholera can produce up to a litre of diarrhoea every hour which can cause severe dehydration. Diarrhoea caused by cholera is sometimes described as “rice water stools” because it has a pale and milky appearance, similar to water in which rice has been boiled. It may also have a fishy smell.

Vomiting – in addition to severe diarrhoea, cholera also causes those infected to vomit, which causes more fluids to be lost. Vomiting also causes any oral antibiotics to be brought back up, so antibiotic treatment has to wait until the patient has stopped vomiting or need to be given through a drip directly into a vein.

Dehydration – because of the massive amount of fluid lost through diarrhoea and vomiting, cholera can cause severe dehydration very quickly. A previously healthy person can become severely dehydrated within a few hours of symptoms appearing, and die within 24 hours if they are not treated.

Other symptoms of cholera include:

  • stomach pain and cramps
  • fever
  • sudden weight loss
  • seizures or convulsions
  • weakness
  • difficulty urinating

How long does it take for the symptoms of cholera to appear?

Cholera has an incubation period (time for symptoms to appear after being infected) of between 6 hours to 5 days. Shorter incubation periods may mean that the symptoms are likely to be more severe, or the person infected is more at risk of the symptoms of cholera, which means immediate treatment may be necessary.

On average, symptoms of cholera will appear 2 to 3 days after infection. Most cases of cholera are quite mild, and may be almost identical to other causes of mild diarrhoea such as food poisoning or stomach bugs. In some cases, you can be infected with cholera and display no symptoms at all.

What increases the risk of cholera symptoms?

Travelling to at-risk areas – people travelling to countries or regions that have poor sanitation or access to clean drinking water are at risk of being infected with cholera. Countries in Sub-Saharan Africa and South-East Asia have the highest risk for cholera, while 80% of reported cases of cholera come from just 5 countries: Afghanistan, Democratic Republic of the Congo, Haiti, Kenya, and Tanzania.

Most travellers are at a low risk of getting cholera, even in at-risk areas, as travellers do not usually engage in high-risk behaviour such as drinking from contaminated sources of water. However those travelling to high-risk areas for work purposes, such as relief workers, or for a long period of time are at a higher risk.

Being malnourished – those who are not able to get enough nutrients in their diet are more at risk of developing cholera, as their immune system is not strong enough to effectively fight off the infection. As people in impoverished regions are more likely to be both malnourished and have more limited access to clean drinking water and adequate sanitation, cholera is more prevalent in these areas.

Low amount of stomach acid – the bacteria that causes cholera infects the stomach and the intestines, but it is very sensitive to stomach acid. People with lower levels of stomach acid are more susceptible to severe infections as it normally acts as a barrier to the disease. This can be caused by a number of factors, including vitamin deficiencies, stress, and smoking.

Close contact with infected people – while cholera rarely spreads directly from one person to another, living in close quarters with someone who is infected increases the likelihood that they will contaminate the food and/or water of other people in the area.

A suppressed or compromised immune system –  those who are immunosuppressed, for example those taking medication that suppresses their immune system, or those that have diseases such as HIV, are more at risk of developing cholera and its complications.

Type O blood – for reasons that are not yet fully understood, there is a strong link between cholera and people with type O blood. People with type O blood are not more likely to get cholera, but are likely to experience more severe symptoms if they are infected. There is a suggestion that cholera has had an impact on human evolution, as type O blood is less common in areas where cholera is prevalent (such as in the Ganges delta) compared to other regions of the world.

Raw or undercooked shellfish – in addition to being spread by contaminated sewage, cholera also occurs naturally in shellfish. The bacteria that causes cholera is sensitive to heat and will be killed off in the cooking process, so if infected shellfish is eaten raw or is not cooked properly, the bacteria inside will still be alive and could cause an infection.

How are the symptoms of cholera treated?

Rehydration – the primary cause of death in cholera is dehydration due to fluid loss, which is easily treated with rehydration solutions. Rehydration solutions are fluids used to treat dehydration, and are typically made up of clean water mixed with certain sugars and salts, such as sodium and potassium, which are lost through sweat, diarrhoea, or vomit. In most cases, oral rehydration solutions are good enough to treat the symptoms of cholera while the body fights off the bacteria. In more severe cases of cholera where the patient is unable to take fluids themselves or need rapid rehydration, then the rehydration solution may be given intravenously (straight into the veins).

Antibiotics – cholera is caused by some strains of the Vibrio cholerae bacteria, which can be treated with certain antibiotics. Antibiotics will only be prescribed in severe cases of cholera due to the growing threat of antibiotic resistance. Those who receive rehydration treatment, but do not receive antibiotic treatment, will recover in about 4 to 5 days, which is reduced to about 2 to 3 days with antibiotics.

Zinc – research has shown that zinc supplements can help to lessen the severity of the symptoms of cholera, and shorten the amount of time that a patient has diarrhoea. A study in Bangladesh showed that children who were given zinc supplements, in addition to rehydration and antibiotic treatment, experienced diarrhoea for 8 fewer hours than children who did not receive zinc supplements.