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Definition

Cholera is an acute infectious disease caused by a bacterium, Vibrio cholerae. This bacteria multiplies rapidly in the intestine and produces a powerful toxin that causes severe diarrhea with fluid loss.
The bacterium that causes cholera is Gram-negative and is comma- or rod-shaped and is also known as cholera vibrio. Only two serotypes produce the toxin that affect the intestine, V. cholerea O1 (“classic” or “El Tor”) and V. cholerea O139.

Epidemiology

Cholera is a fecal-oral transmission disease, therefore, developing countries with precarious health policies are the most affected. Between 1817 and 1923, cholera caused 6 pandemics. Regions such as India, Latin America, Africa and tropical areas of Asia are often affected. Between 2008 and 2009, the World Health Organization (WHO) recorded an outbreak of cholera in Zimbabwe, with a record of 98,000 cases.

In South America, the first epidemic occurred in 1991 in Peru. Still this year, Brazil registered 2,103 cases of cholera and 33 deaths. In 1992, the numbers increased to 37,572 cases and 462 deaths. In 1994, there were 60,044 cases of the disease with 650 deaths and in May 1994 the WHO announced that Brazil was the most affected country in the world with a greater number of cases than El Salvador and Peru.

It is estimated that in the 19th century, cholera caused the death of millions of people.

World (2019)
The number of reported cholera cases worldwide decreased considerably during 2019 (until December 2019), according to the World Health Organization (WHO). The WHO indicated on December 19, 2019 that in 2018, this number was 60% lower than in 2017, and that the situation had improved mainly in countries in civil war like Yemen, as well as in Congo, Somalia and South Sudan . However, the number of reported cholera cases varies widely, with an exceptional number in 2017. At that time, over 1.2 million cases were reported, up from less than 200,000 the year before.

Causes

The cholera vibrio strains that produce the toxin are V. cholerea O1 and V. cholerea O139. The toxin produced by the bacteria is known as cholera enterotoxin, which has two portions in its molecule: portion A and B. This toxin causes an alteration in the chloride channels of intestinal cells, leading to intense secretion of sodium, chloride and water. The cholera vibrio does not invade the cells, remaining only in the intestinal lumen.

cholera transmission

Transmission is via the fecal-oral route and occurs mainly through the ingestion of water and/or raw or undercooked food contaminated by feces or vomits of patients. Objects and kitchen utensils can also be sources of transmission because they are in contact with contaminated water.

Some types of food are common sources of transmission of the bacteria that cause cholera. Among them, fish and seafood, raw fruits and vegetables, grains and water from wells and spouts stand out.

Other forms of transmission are through flies or handling food by dirty hands. In addition, contagion can be from person to person through direct contact.

Groups of risk

People who live in precarious sanitary supply regions, without basic hygiene measures, constitute the main risk group. In addition, travelers who visit places affected by the disease and without basic sanitation, such as in regions of Africa and India, can be contaminated and return with the disease to the country, being a source of transmission.

Low gastric acid production (hypochlorhydria or achlorhydria) also contributes to the survival of cholera-causing bacteria. Another risk group are patients with blood type O. The responsible factors are not yet known, however, it is known that patients with this blood type are twice as likely to develop cholera.

Symptoms

The incubation of the causative bacteria is about five days. After this period, diarrhea and vomiting appear . Cholera ranges from mild symptoms to severe diarrhea with heavy fluid loss. It is noted that in numerous cholera infections, people have no or few symptoms (asymptomatic).

In the mildest form, which corresponds to about 90% of cases, the initial diarrhea is discreet, with occasional vomiting. Children may also have a fever and, in some cases, the presence of mucus in the stool and convulsions, as well as extreme tiredness, fatigue and fainting.

In severe cases (about 10%), the onset is abrupt, with intense diarrhea. Water loss can reach 20 liters per day, which causes hydroelectrolytic and metabolic imbalance. In this phase, symptoms can be: thirst, rapid weight loss, tachycardia, rapid and weak pulse, low blood pressure, fatigue, prostration, among others.

Electrolyte imbalance and intense fluid loss cause muscle cramps and hypovolemic shock. Shock is a severe and severe condition in which the blood volume decreases and with it the amount of oxygen delivered to the tissues.

Diagnosis

Diagnosis is usually made by culture of stool specimens from the patient or suspects.

The collection of material can be done by rectal or fecal swab or collection on filter paper. Clinical data and knowledge of the area from which the patient came also aid in research, without the need for laboratory data.

In general, it is advisable to make this diagnosis in isolated cases of cholera, in outbreak cases this method of diagnosis is not recommended, probably because it would be too expensive and time consuming.

Rapid tests for identification of cholera bacteria are now available in order to help health professionals diagnose the disease in remote regions that do not have access to health posts or hospitals. Rapid diagnosis of cholera helps isolate cases and prevents the disease from spreading.

Complications

Due to the intense loss of fluids and salts during diarrhea , dehydration and a decrease in blood volume can occur. When dehydration is not properly corrected and treated, there is cyanosis, coldness of the extremities, loss of important mineral salts such as potassium (leading to hypokalemia and cardiac arrhythmia), hypoglycemia, peripheral collapse, hypovolemic shock (due to reduced blood volume), decreased urine production, kidney failure (usually accompanied by shock), coma, and in some cases, death. Elderly patients and children are most affected by dehydration.

Treatment

Initial treatment consists of providing the patient with fluids and mineral salts lost in diarrhea. Rehydration can be done by an oral solution containing glucose. The composition recommended by the World Health Organization is as follows (amounts to be dissolved in 1 liter of filtered water):

You should know that with rapid rehydration, the death rate from cholera is less than 1%.

Another measure, depending on the degree of dehydration, is parenteral rehydration with lactated Ringer’s solution.

For severe forms of the disease, in addition to rehydration, antibiotic therapy is necessary which, when started within the first 24 hours of the disease, reduces the duration of diarrhea and, therefore, the loss of salts and liquids. Commonly used antibiotics are tetracycline, doxycycline, norfloxacin, ciprofloxacin and furazolidone and their use should be monitored by a physician.

Anti-diarrheal drugs are contraindicated in the case of cholera, since they reduce the peristaltic movements of the intestine and encourage the multiplication of V. cholerae.

There are envelopes in pharmacies containing the correct amounts of salts and sugar to prepare a rehydration solution. The contents of the envelope must be dissolved in 1 liter of boiled water, after cooling and can be kept in the refrigerator for up to 1 day. In the case of infants, breastfeeding should be continued.

In most cases, recovery is quick and rehydration is sufficient to treat the patient.

Research has shown that supplements containing the element zinc help reduce the intensity and duration of diarrhea, especially in children.

cholera vaccine

Currently, there are vaccines against cholera. These vaccines are not 100% effective, it is estimated that their effectiveness is around 70%, some sources such as the Swiss website pharmavista.net talk about 85% protection in 6 months.
Vaccination must be repeated more often, because the duration of its effect is usually 6 months. Also note that some strains of V. cholerae do not have a vaccine.

Vaccination should not replace preventive measures.

Vaccination is not recommended for travellers, even those visiting risk areas (except medical exceptions).

Tips

Some tips are useful when the patient has cholera:

– When preparing homemade whey, always use filtered or boiled water and, after cooling, prepare the solution;

– Consume plenty of fluids during illness to avoid dehydration. It is recommended that the patient start eating food 3 to 4 hours after accepting the homemade serum;

– Do not consume antibiotics without medical advice. They, when used improperly, can increase the resistance of the cholera vibrio;

– Do not use medicines against diarrhea, they can worsen the condition of cholera;

– Quickly look for a health center if you suspect the disease.

Prevention

Hygiene measures help prevent cholera. Some of them are:

– Always drink potable water. If you don’t have it, boil water and add sodium hypochlorite (distributed at health centers) before consumption. The WHO recommends 6 mg of chlorine for every liter of water.

– Wash fruits and vegetables well before eating.

– Eat well-cooked foods, especially vegetables and seafood.

– Peel fruits and vegetables.

– Avoid using ice.

– Brush your teeth with bottled water.

– Take precautions with dairy foods such as cheese and ice cream.

– In endemic regions, avoid raw or undercooked foods, such as sushi.

– Dispose of rubbish in suitable places.

– Protect food after cooking.

– Maintain good personal hygiene habits, such as always washing your hands before consuming food, taking baths, among others.

– If you are a traveller, always check the sanitary conditions of the place you are going to. Always be prepared.

– Carry out a disinfection several times a day, especially before meals, with a hydroalcoholic lotion (containing 70% alcohol).

– The vaccine offers protection against cholera, but not total. Some sources speak of an efficiency of up to 85% (see above under Treatments for more information). Talk to your doctor for more information about getting vaccinated against cholera.

Jeanne Kenney
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I’m a stylist trainer, a content creator, and an entrepreneur passion. Virgo sign and Pisces ascendant, I move easily between my dreams, the crazy world I want, and my feet on the ground to carry out my projects.

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