Cholera: cause, prevention, transmission, symptoms, treatments

What is cholera?

Cholera is an intestinal infection caused by Vibrio cholerae , a bacterium that usually lives in water. Its main symptoms are diarrhea and vomiting that can lead to dehydration.

Well known for the epidemics between 1817 and 1923, cholera is a disease that is still very present today. In Brazil, the disease reappeared in 1991, especially in the Amazon region, however the cases have become more scarce with time.

Worldwide, the disease is responsible for between 28 thousand and 142 thousand deaths every year. In some countries, cholera is endemic and few measures are taken to combat it. According to the World Health Organization (WHO), there are 1.4 to 4.3 million cases globally.

Causes

There are two strains (subtypes) of the bacterium Vibrio cholerae responsible for cholera: V. cholerae O1 (“classic” or “El Tor”) and V. cholerae O139. Although there are about 190 subtypes of this microorganism, only these two release the toxins that cause the symptoms.

Enterotoxins, released by the bacteria in the intestine, are a type of toxic substance that causes gastrointestinal symptoms, especially those that are well known for food poisoning. But calm down! Having food poisoning does not mean you have cholera or vice versa. They are two different diseases.

In general, Vibrio cholerae does not survive gastric acid. However, this can happen, and then it manages to reach the small intestine, where it finds an optimal means for its proliferation. There, it begins to release the enterotoxins, causing the symptoms.

These toxins alter the chloride channels of intestinal cells, which results in a greater secretion of sodium, chloride and water, which give rise to the diarrhea characteristic of cholera.

Streaming

The contagion of cholera occurs through the ingestion of infected food and water. In contrast, food is infected with water that has had contact with the feces of carriers of the bacterium.

This happens most often in areas where there is no basic sanitation and garbage collection is done in an inadequate or scarce manner. In these places, it is common for waste to come in contact with the water used to supply the houses and be consumed as a drink.

Food is often infected with inadequate washing without sterilization of water beforehand. In these cases, the bacteria can survive for up to 5 days at room temperature (between 15 and 40 ºC). It is worth remembering that there is no point in putting food in the refrigerator: the bacteria can survive freezing, it just does not multiply so quickly.

Seafood and fish, in particular, are more likely to be infected due to their aquatic environment. Therefore, the proper cleaning of these types of food is extremely important to prevent cholera.

In nature, too, there are several animals that come into contact with human feces, being infected and carrying the bacteria into the water. However, it only causes disturbance to humans: animals do not get sick or develop symptoms.

Groups of risk

Everyone is susceptible to cholera, but there are some groups that are more likely to contract the disease. Are they:

Residents of areas without basic sanitation

There are many municipalities and large cities, worldwide, that lack the basic sanitation system. In these places, the risk of water contamination is much greater, as waste is discarded in nature and can easily reach water sources.

Travelers

People who often travel to places in the middle of nature are more exposed to this and many other diseases.

Because he needs to “get by” with the available water sources, such as rivers and lagoons, the traveler needs to be prepared with equipment for sterilizing the water. If these are not available or the water is poorly treated, the traveler can easily fall ill.

People with a lack of gastric acid

The bacteria that causes cholera hardly survive gastric acid, which serves as a protection for our body. However, if it is not present due to a medical condition or the use of antacid medications, the chances of suffering an infection increase.

People with blood type O

It is not known why, but people with type O blood are 2 times more likely to develop cholera than people with other blood types.

Eating seafood from unknown waters

Because Vibrio cholerae live in water, it can easily infect seafood. Nowadays, thanks to various technologies, the fish products are very clean and rarely cause any disturbance, but it is still necessary to be careful with fruits that come from unknown waters.

Symptoms

The symptoms of cholera appear after the incubation period of the bacteria, which can vary between 2 hours and 5 days. After that time, most people will experience mild diarrhea. In fact, many of those infected simply have no symptoms . In such cases, there is also a spontaneous cure.

In a minority, the disease develops differently, with much more severe symptoms. The most common are:

  • Intense, watery and grayish diarrhea – aspect of “rice water”;
  • Abdominal pains that resemble colic;
  • Nausea and vomiting;
  • Dehydration;
  • Hypothermia;
  • Weight loss;
  • Loss of voice;
  • Weakness.

In cholera, the diarrhea is so intense that up to 1 liter of water is lost per hour, which easily leads to dehydration. Some symptoms that the body is lacking in water are:

  • Irritability;
  • Lethargy;
  • Eyes sunk in their sockets;
  • Dry mouth;
  • Intense venue;
  • Dry, wrinkled skin that takes time to get back in place when pulled;
  • Lack of urination (anuria);
  • Low pressure;
  • Acceleration of heart rate (tachycardia).

Due to dehydration, an electrolyte imbalance, characterized by cramps, can develop. In addition, this condition can lead to a hypovolemic shock – a reduction in the volume of blood flowing through the body – which can kill in a short time if left untreated.

As soon as the symptoms are noticed, the patient must be quickly seen by a doctor in order to prevent mortality.

In children

In general, the symptoms of cholera in children are not much different than in adults. However, due to the greater ease of hypoglycemia with fluid loss, they may experience seizures , altered states of consciousness and even coma . Fever and drowsiness are also common in children.

Complications

When the disease develops, the symptoms can be severe and lead to some complications. Are they:

Dehydration

In cholera, the loss of water can reach up to 20 liters per day. The rapid elimination of fluids by diarrhea and vomiting causes the loss of electrolytes in the body. This condition brings a series of dangerous developments such as cardiac arrhythmia , hypoglycemia, kidney failure, decreased urine production, among others.

Hypoglycemia

Along with all the fluids, the infected individual also loses the glucose present in the blood – which is the main source of energy in the body – especially when he does not have the strength to eat and replenish the nutrients.

In this way, the person may have seizures, lose consciousness and, in more severe cases, die.

Hypokalemia

Cholera leads to loss of potassium and other minerals by diarrhea. Lack of potassium is life-threatening as it interferes with cardiac and nervous activity.

Renal insufficiency

Intense fluid loss and dehydration prevent the kidneys from functioning properly. In this way, toxic and useless substances for the body get trapped in the blood. Generally, renal failure due to cholera contributes to the development of hypovolemic shock.

Hypovolemic shock

This condition is characterized by a reduction in the volume of blood, which overloads the heart because, in order to irrigate all tissues, it needs to pump harder and faster because of the lesser amount of blood. Hypovolemic shock is highly fatal and a major cause of death from cholera.

Cholera kills?

Due to the aforementioned complications, cholera leads to death quickly. When left untreated, more serious cases can kill in a matter of hours.

How is cholera diagnosed?

Because it is a bacterial infection, cholera should be diagnosed as soon as possible. Therefore, the first part of the diagnosis that already makes room for the start of treatment is the patient’s history .

If the patient has a clinical picture of severe diarrhea and has had contact with areas where basic sanitation is lacking, for example, the suspicion of cholera is very high. In this way, the doctor – usually a general practitioner or infectious disease – can already outline the first stage of treatment: hydration.

Then, he can order a stool test to identify the microorganism. In some cases, you can perform a rectal or fecal swab (collection of material with a kind of sterile cotton swab) or a collection on filter paper. However, this method is used only when there are isolated episodes of the disease, because in outbreaks this type of examination would be very time-consuming.

Is cholera curable?

Fortunately, yes, cholera is curable ! In asymptomatic cases, it usually resolves spontaneously because the organism finds a way to kill the bacteria. In cases where there are severe symptoms, with the proper treatment, a cure is easily achieved.

How to deal with?

The first part of cholera treatment is rehydration. Then, if necessary, medications can be administered.

Rehydration

Due to the loss of salts, rehydration is not only done with large amounts of water. In fact, an electrolyte-rich solution is used to restore the body’s water balance.

The solution is prepared with water, sugar and salt. Yes, sweet and salty in the same proportion! Perhaps the taste is not the most pleasant, but it works. Often, depending on the individual’s condition, the solution will be administered intravenously.

The World Health Organization (WHO) suggests the following amounts for rehydration solution:

Sodium chloride

3,5g

Trissodium citrate, dihydrated

2,9g

Potassium chloride

1,5g

Glucose

20,0g

Cholera medications

When necessary, antibiotics are administered to eliminate the bacteria, especially doxycycline .

In contrast, there are many rehydrating drugs on the market that can be administered, such as:

  • Floralyte ;
  • Hidrafix ;
  • Pedialyte.

Antidiarrheals should not be used , as these drugs reduce bowel movements that expel feces, which makes the environment even more friendly for the proliferation of bacteria.

Attention!

NEVER self-medicate or stop using a medication without first consulting a doctor. Only he will be able to tell which medication, dosage and duration of treatment is the most suitable for his specific case. The information contained in this website is only intended to inform, not in any way intended to replace the guidance of a specialist or serve as a recommendation for any type of treatment. Always follow the instructions on the package insert and, if symptoms persist, seek medical or pharmaceutical advice.

Prevention: how to prevent cholera?

Unfortunately, the prevention of cholera does not depend only on the individual, as basic sanitation promoted by city halls is the best prevention. This is because this system keeps waste away from water sources that supply homes.

However, this alone is not enough to prevent the disease. Some tips are:

  • Wash your hands with soap and water frequently, especially before preparing food and after using the bathroom;
  • Always use drinking water (sterile or filtered) to drink or prepare food – avoid water of doubtful origin;
  • Leave greens and vegetables that are eaten raw in a water solution with a few drops of vinegar for at least 20 minutes before consumption;
  • Avoid eating in street stalls or what is sold by street vendors, as the origin of these foods is not known;
  • Food should be well cooked and served right after preparation, still warm. If they are served later, the ideal is to reheat before consumption;
  • Do not use ice cubes in drinks unless they have been prepared with treated water.

Vaccines

Although little known, there are some vaccines on the market available for cholera prevention: Dukarol and Sanchol. However, they are rarely recommended as they prevent only 50% of cases and immunization is short-lived: it works for only 3 months.

Doctors do not usually recommend them even for people who will be traveling to places where there is a higher incidence of cholera. The prescription is usually made only in cases of high risk and in people who have problems in the production of gastric acid.

How to treat water?

If you are a traveler or live in a place where the water is not very well treated, it is worthwhile to learn how to treat it yourself before consuming it and taking the risk of contracting some disease.

Even in large cities with adequate conditions, water treatment at home is also recommended, as treatment at stations may not be enough in some cases.

Fortunately, treating water is very simple and there are several ways! Understand:

Boil

Boiling water is probably one of the best methods of disinfection. This is because several of the microorganisms present in the water do not resist heat and die quickly.

To eliminate most microorganisms, including Vibrio cholerae , you must boil the water for at least 5 minutes.

Don’t think that putting the water to heat for 5 minutes will do the job, no! It only counts 5 minutes from the moment it reaches boiling , that is, when it is in a state of agitation with the formation of large gas bubbles.

Of course, the water, as soon as it comes out of the fire, does not taste the best in the world. Therefore, if you prefer to consume later, store it in a properly sterilized container, with a lid, in a cool place.

Chlorine disinfection

Chlorine is a substance capable of eliminating several microorganisms that cause diseases in water. However, it is not just any chlorine that can be used for human consumption! The most suitable in these cases is sodium hypochlorite or bleach.

For each liter of water, only 2 drops (6 mL) of sodium hypochlorite between 2 and 2.5% should be added. Concentrations greater than this are harmful to health!

Bleach, in turn, is sodium hypochlorite mixed with water, that is, it ends up being a little weaker than hypochlorite. However, this does not mean that it should be used in higher concentrations, as it is also harmful! Just 2 drops per liter of water is enough.

Alternatively, there are some products on the market to aid in the disinfection of water, which should be used according to the indication of each manufacturer. Hydrosteril and Chlor-in are some examples.

Attention!

Not all bleach is suitable for disinfection, as some manufacturers may add other substances unsuitable for consumption. Always make sure that the bleach is composed only of water and sodium hypochlorite. If there is any other component in the list of ingredients, avoid using it.


Well-known for the pandemic of the 60s, cholera is an easily treatable disease, but it must be treated quickly in order to avoid complications. If you have recently been in an area where there is no basic sanitation and you have symptoms, see a doctor as soon as possible.

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