Everything you need to know about cholera
Cholera is an acute epidemic infectious disease. It is characterized by watery diarrhea, extreme loss of fluid and electrolytes, and severe dehydration. It can be fatal.
The cause of cholera is infection by the bacterium Vibrio cholera (V. cholera). These bacteria were discovered in 1883. V. cholera bacteria live in shallow, salty water on microscopic crustaceans. They can also exist as colonies of biofilms that coat the surface of the water, plants, stones, shells, and similar items, and they can live among the eggs of midges, which serve as a reservoir for cholera bacteria.
Toxic strains of cholera bacteria produce a poison that triggers violent diarrhea in humans.
When the bacteria enter areas where humans live, they can quickly cause severe epidemics. Weather changes, population loss, and improved sanitation can all end an outbreak.
Despite being easy to treat, cholera is estimated to affect between 3 and 5 million people each year, and it causes over 100,000 deaths worldwide.
Due to severe dehydration, fatality rates are high when untreated, especially among children and infants. Death can occur in otherwise healthy adults within hours. Those who recover usually have long-term immunity against re-infection.
People need to protect themselves against cholera by having the appropriate vaccinations beforehand, drinking only water that is boiled or from a sealed bottle and following good handwashing practices.
Diarrhea is the key symptom of cholera.
Only around 1 in 20 cholera infections are severe, and a high percentage of infected people show no symptoms.
If symptoms appear, they will do so between 12 hours and 5 days after exposure. They range from mild or asymptomatic to severe.
They typically include:
A person with cholera can quickly lose fluids, up to 20 liters a day, so severe dehydration and shock can occur.
Signs of dehydration include:
Shock can lead to collapse of the circulatory system. It is a life-threatening condition and a medical emergency.
Cholera is more common where there is overcrowding and poor sanitation.
Cholera bacteria enter the body through the mouth, often in food or water that has been contaminated with human waste, due to poor sanitation and hygiene.
They can also enter by eating seafood that is raw or not completely cooked, such as fish native to estuary environments, oysters or crabs.
Poorly cleaned vegetables irrigated by contaminated water sources are also another common source of infection.
In situations where sanitation is severely challenged, such as in refugee camps or communities with highly limited water resources, a single affected victim can contaminate all the water for an entire population.
A doctor may suspect cholera if a patient has severe watery diarrhea, vomiting, and rapid dehydration, especially if they have recently travelled to a place that has a recent history of cholera, or poor sanitation, or if they have recently consumed shellfish.
A stool sample will be sent to a laboratory for testing, but if cholera is suspected, the patient must begin treatment even before the results come back.
It is normally dehydration that leads to death from cholera, so the most important treatment is to give oral hydration solution (ORS), also known as oral rehydration therapy (ORT).
The treatment consists of large volumes of water mixed with a blend of sugar and salts.
Pre-packaged mixtures are commercially available, but widespread distribution in developing countries is limited by cost, so homemade ORS recipes are often used, with common household ingredients.
Severe cases of cholera require intravenous fluid replacement. An adult weighing 70 kilograms will need at least 7 litres of intravenous fluids.
Antibiotics can also shorten the duration of the illness, but the WHO does not recommend the mass use of antibiotics for cholera, because of the growing risk of bacterial resistance.
Anti-diarrheal medicines are not used because they prevent the bacteria from being flushed out of the body.
Cholera is often spread through food and because of poor hygiene. Some simple measures can reduce the risk of contracting cholera.
When traveling in areas where the disease is endemic, it is important to:
Travelers and visitors should learn about cholera before visiting any area where it is prevalent.
Individuals should seek medical attention immediately if they experience symptoms such as leg cramps, vomiting, and diarrhea while in a community where the disease exists. In the event one suspects they have contracted the disease on campus the Clinic is the first port of call.
There are currently three cholera vaccines recommended by the World Health Organization (WHO). These are Dukoral, Shanchol, and Euvichol.
All three require two doses to give full protection.
Dukoral needs to be taken with clean water, and it provides roughly 65 percent protection for 2 years. Shanchol and Euvichol do not need to be taken with water, and they provide 65 percent protection for 5 years. All the vaccines offer higher protection nearer to the time they are given.
People most at risk of consuming food or water infected with the V. cholera include:
Wide-spreading epidemics of cholera often occur due to water supplies that are contaminated with human waste and street food vendors.
The following people are also at risk of a more severe reaction to V. cholera than others: