Cholera (Vibrio Cholerae Infection): Symptoms, Causes, Diagnosis & Treatment

Cholera (Vibrio Cholerae Infection): Symptoms, Causes, Diagnosis & Treatment

Cholera is an intestinal infection caused by Vibrio Cholerae. The hallmark of the disease is profuse secretory diarrhea. Cholera can be endemic, epidemic, or pandemic. Despite all the major advances in research, the condition still remains a challenge to the modern medical world. Although the disease may be asymptomatic or mild, severe cholera can cause dehydration and death within hours of onset. Many infections are associated with milder diarrhea or have no symptoms at all. If left untreated, 25-50% of severe cholera cases can be fatal. In nonendemic areas, the incidence of infection is similar in all age groups, although adults are less likely to become symptomatic than are children. The exception is breastfed children, who are protected against severe disease because of less exposure and because of the antibodies to cholera that they obtain in breast milk.

Cholera is a major cause of epidemic diarrhea throughout the developing world. There has been an ongoing global pandemic in Asia, Africa, and Latin America for the last five decades. In 2016, a total of 38 countries reported a cumulative total of 132,121 cases including 2,420 deaths (case fatality rate of 1.8%) to the World Health Organization (WHO). Cholera is underreported, and as many as 2.9 million cases and 95,000 deaths are suspected to actually occur each year. Resource-poor areas continue to report the vast majority of cases, with the African continent having the highest case fatality rates.

Cholera is transmitted through contaminated food or drinking water, as well as by person-to-person contact through the fecal-oral route. Sanitary conditions in the environment play an important role since the Vibrio Cholerae bacterium survives and multiplies outside the human body and can spread rapidly where living conditions are crowded, water sources are unprotected, and where there is no safe disposal of feces.

Vibrio Cholerae is a curved and a rod-shaped bacterium that is responsible for the cause of this disease. It is basically present in the free-living cells of living organisms and also found in coastal areas. It also lives in the small intestine of the human body, being one of the major contaminants in the sewage. The contamination of drinking water owing to the human wasteful activities also leads to this disease. This bacterium in the small intestine releases an exo-toxin in the body. This causes a flow of water, and certain electrolytes such as sodium bicarbonate, chloride, etc., into the small intestine.

Cholera can’t be self-diagnosed, it requires a medical diagnosis. Key symptoms are diarrhoea and dehydration. Rarely, shock and seizures may occur in severe cases.

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How Does Cholera Affect Your Body?

When the bacteria that cause cholera enter the body, some of it can be killed by stomach acid. However, some of the bacteria travel to the small intestine, causing the loss of large amounts of salt and water in the form of watery diarrhea. The resulting dehydration, when severe, can cause death.

What Are The Causes of Cholera?

Vibrio Cholerae is the causative agent responsible for cholera. It is a bean-shaped bacterium with a long tail that it uses for self-propulsion. The bacteria are transmitted between humans through the fecal-oral route. A bite of contaminated food or a sip of contaminated water can cause infection.

More specifically, a toxin secreted by the bacteria, which targets receptors in the human intestine, is responsible for the pathology characteristic of the disease.

  • Uncontrolled water sources such as wells, lakes, ponds, streams, and rivers pose a great threat.
  • Ingestion of contaminated food and drinks has been associated with outbreaks of cholera.
  • Bottle feeding could be a significant risk factor for infants. Fruits and vegetables washed with contaminated water can be a source of infection too.
  • After preparation, cooked food may be contaminated through contaminated hands and/or flies.
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What Are The Risk Factors of Cholera?

Risk factors of cholera include:

  • Unclean conditions (such as poor sanitation and contaminated water)
  • Low levels of stomach acid (cholera bacteria cannot live in highly acidic environments)
  • Sick household members
  • Type O blood (it’s not clear why this is true, but more people with this blood type seem to be at risk for cholera)
  • Eating raw shellfish (if the shellfish live in dirty waters where the cholera bacteria live, there is a greater risk of becoming ill)
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What Are The Symptoms of Cholera?

The symptoms of Cholera start suddenly, usually within one to five days after the infection. Primary symptoms of cholera are as follows:

  • Profuse diarrhea sometimes called “rice water stools”
  • Abdominal pain
  • Vomiting
  • Leg cramps
  • Rapid pulse
  • Unusual sleepiness
  • Lethargy
  • Nausea
  • Excessive thirst, lack of tears, and low urine output

Untreated cholera patients suffer a rapid loss of fluids and severe dehydration due to excessive diarrhea. Shock can also occur in such individuals. If the fluid is not replaced, death may be inevitable within a few hours. Signs of dehydration include:

  • Loss of skin elasticity
  • Sunken eyes
  • Fast heartbeat
  • Low blood pressure
  • Rapid weight loss
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How is Cholera Diagnosed?

Diagnosis of cholera involves the following:

  • Assessment of symptoms  – This typically includes assessing watery diarrhea along with nausea, vomiting, and abdominal cramps.
  • Culture method – Stool samples are taken from a patient using a sterile cotton bud and are placed on a plate containing TCBS (thiosulphate citrate bile salts) and agar i.e. a selective medium that isolates the bacteria from diarrhea. On incubation, Vibrio Cholerae appear as yellow clumps which are then analyzed to detect the exact strain of cholera. This definitive diagnosis allows cholera to be distinguished from other bacterial, protozoal or viral causes of dysentery.
  • Rapid immunochromatographic dipstick test – A dipstick strip is placed into a stool sample and the lines it displays are read. Cholera is confirmed if two red lines appear on the dipstick, whereas it is ruled out if only one line appears. It takes between 2 and 15 minutes for the test to make a diagnosis.
  • Antibody test – Diagnosis can also be made on testing blood for antibodies against Vibrio Cholerae.
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How To Prevent And Control Cholera?

Cholera can be prevented by adopting the following methods:

  • Drink and use safe water. Bottled water with unbroken seals and canned/bottled carbonated beverages are safe to drink and use. Use safe water to brush teeth, wash and prepare food, and to make ice. Food preparation areas and kitchenware should be cleaned with soap and safe water and should be let dry completely before reuse.
  • Wash hands often with soap and safe water. They should be washed before eating or preparing food, before feeding children, after using the toilet, after cleaning a child’s bottom, and after taking care of someone ill with diarrhea.
  • Use latrines or bury the feces (poop). Do not defecate in any body of water.
  • Use latrines or other sanitation systems, like chemical toilets, to dispose of feces.
  • Wash hands with soap and safe water after defecating.
  • Clean latrines and surfaces contaminated with feces, using a solution of 1 part household bleach to 9 parts water.
  • Cook food well, keep it covered, eat it hot, and peel fruits and vegetables.
  • Clean the kitchen and places where the family bathes and washes clothes, safely and properly.
  • Wash self, children, diapers, and clothes, 30 meters (98 feet) away from drinking water sources as a preventive measure.

Treatment of Cholera

Treatment of cholera includes:

  • Rehydration – To replace lost fluids and electrolytes using a simple rehydration solution i.e. oral rehydration salts (ORS). The ORS solution is available as a powder that can be reconstituted in boiled or bottled water.
  • Intravenous fluids – During a cholera epidemic, most people can be helped by oral rehydration alone, but severely dehydrated people may also need intravenous fluids.
  • Antibiotics – While antibiotics are not a necessary part of the cholera treatment, some of these drugs may reduce both, the amount and duration of cholera-related diarrhea for people who are severely ill. Effective antibiotics against cholera include tetracycline, doxycycline (Vibramycin), sulfa drugs such as trimethoprim (Primsol) and trimethoprim/sulfamethoxazole (Bactrim), ciprofloxacin (Cipro), erythromycin (Ery-Tab), and azithromycin (Zithromax).
  • Zinc supplements – Research has shown that zinc may decrease and shorten the duration of diarrhea in children with cholera.
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Cholera – Lifestyle Tips

As such cholera requires immediate medical attention. Meanwhile, these tips should be followed:

  • ORS can successfully treat 80% of cholera cases.
  • Appropriate antibiotics can reduce the duration of purging.

What Are The Recommended Exercises For a Person With Cholera?

There are no particular exercises recommended for people with cholera. One can continue with their regular exercise routine.

Cholera And Pregnancy – Things to Know

Cholera infections during pregnancy are associated with high rates of fetal death, especially when women are severely dehydrated. Third-trimester gestation, younger maternal age, severe dehydration, and vomiting, are risk factors. Changes in treatment have limited effects on fetal death, highlighting the need for prevention and evidence-based treatment.

Common Complications Related to Cholera

The complications of untreated cholera are:

  • Shock and death from massive fluid loss / Massive electrolyte loss can also lead to lethal cardiac rhythm disturbances and seizures
  • Low blood sugar
  • Low potassium levels
  • Kidney failure
  • Hypovolemic shock
  • Food poisoning
  • Secretory diarrhea
  • Hypoglycemia
  • Sepsis
  • Bowel complications
  • Premature labor or miscarriage
  • Severe hypokalemia
  • Circulatory collapse

Other FAQs about Cholera

Q. How is the disease transmitted?

A. Ingestion of fecally contaminated water is the most common source of transmission of cholera; therefore, it can easily spread in highly populated communities where access to clean water and sanitation are poor and when hygiene is compromised by insufficient hand washing and during food preparation. Cholera may also be transmitted via contaminated shellfish and food.

Q. Are there mild and severe cases of cholera, or are they all the same intensity?

A. Most cholera infections (about 80%) are mild or unapparent. Among those who are infected, some develop severe dehydration from profuse, acute, watery diarrhea. After an incubation period of 1-3 days, about 20% will develop diarrhea which may be severe, along with severe vomiting. As the illness progresses, the stools become like water with little flecks of mucus (called rice-water stool). The diarrhea is usually painless and may have a fishy smell. Patients may also have severe muscle cramps and spasms which can be very painful.

Q. What exactly do the bacteria do to cause such severe diarrhea?

A. If a large enough dose of the bacteria is ingested and survives the acidity of the stomach, the bacteria then colonize the small intestine where they release cholera toxin. This toxin triggers mechanisms which eventually lead to a massive purging of electrolyte-rich fluid in the small intestine that exceeds the absorptive capacity of the colon and is expelled as diarrhea. This loss of fluid and depletion of electrolytes can lead to rapid dehydration.

After ingestion of a large enough dose of the bacteria that are able to survive the gastric acidity, the Vibrio organisms then colonize mucosal cells of the small intestine. During this time, the organisms release cholera toxin that binds to the small intestinal epithelial cells. The release of the A subunit of the cholera toxin stimulates the enzyme system of the intestinal cells leading to the increase in chloride secretion by the crypt cells, which in turn leads to inhibition of absorption of sodium and chloride by the microvilli. These events eventually lead to the massive purging of electrolyte-rich isotonic fluid in the small intestine that exceeds the absorptive capacity of the colon, resulting in rapid dehydration and depletion of electrolytes, including sodium, chloride, bicarbonate, and potassium.

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