Cholera: Causes, Symptoms, Types of Carriers, Risk Factors, Diagnosis, Treatment

The bacteria Vibrio cholerae is what causes the infectious disease cholera. Cholera is primarily spread by contaminated water. It is also known as Blue beath because due to severe dehydration, the blood becomes thickened in the vessels leading to depletion of oxygen which leads to bluish discolouration of the skin.

The majority of cholera victims show little to no symptoms, although a handful develop severe diarrhoea and dehydration.

In severe cases, rapid treatment is required because death can happen in just a few hours. Even if someone were in a healthy state before being infected with cholera, this is still possible.

The majority of nations have successfully eradicated cholera because of modern sewage and water treatment. In some areas of Asia, Latin America, Africa, and the Middle East, it is still a problem.

When exactly did Cholera Start to Impact People?

Early writings about cholera-like disorders can be found in manuscripts from India (Sushruta Samhita, 5th century B.C. ), Greece (Hippocrates, 4th century B.C. ), and Cappadocia (Areteus, 1st century A.D.).

Gaspar Correa, a Portuguese historian and the author of Legendary India, provided one of the first in-depth accounts of a cholera pandemic. He documented a sickness outbreak in the Ganges Delta, a region in south Asia that includes Bangladesh and India, in the spring of 1543. The sickness was known locally as "moryxy," and it is said to have killed victims within 8 hours of exhibiting symptoms. The disease's high fatality rate made it difficult for locals to bury all the dead.

Over the following several centuries, observers from Portugal, the Netherlands, France, and Britain reported several cases of cholera along India's west coast.

The Initial Cholera Epidemic

With an epidemic in Jessore, India, in 1817, caused by tainted rice, the Ganges Delta gave rise to the first cholera pandemic. By using trade channels created by Europeans, the disease soon spread throughout the majority of India, contemporary Myanmar, and contemporary Sri Lanka.

Cholera had already spread to Thailand, Indonesia (where it killed 100,000 people on the island of Java alone), and the Philippines by 1820. The disease originated in Thailand and Indonesia and was transported by infected individuals on ships to China in 1820 and Japan in 1822. Moreover, it grew outside of Asia. The Persian Gulf was infected with cholera in 1821 by British troops moving from India to Oman. Later, the epidemic spread to Europe, touching down in Southern Russia, Turkey, and Syria.

A harsh winter in 1823–1824, which may have destroyed the bacteria residing in water supplies, is likely to blame for the pandemic's six-year death toll.

Americas and Europe are both affected by cholera.

Beginning in 1829, there was a second cholera pandemic.

The second pandemic is believed to have originated in India, and like the first, it travelled along commercial and military routes to Eastern and Central Asia, as well as the Middle East.

Cholera reached Moscow by the autumn of 1830. The disease's spread briefly slowed during the winter, but it quickly resumed in the spring of 1831, reaching Finland and Poland. Germany and Hungary were next it entered.

Later, the illness spread across all of Europe, making its first appearance in Great Britain via the ports of Sunderland and London in late 1831 and early 1832, respectively. Quarantines were implemented and local health boards were established in Britain as part of a number of measures to help stop the disease's spread.

However, widespread disease-related apprehension and mistrust of authorities, especially doctors, seized the populace. People started to assume that victims brought to hospitals were slain by doctors for anatomical dissection, a consequence they referred to as "Burking," and that more victims died there than at home as a result of inaccurate journalistic coverage. Several "cholera riots" broke out in Liverpool as a result of this concern.

The Americas had also been colonised by cholera in 1832. In June of that year, the plague claimed 1,000 lives in Quebec as it rapidly spread along the St. Lawrence River and its tributaries.

Cholera was imported into the country during the same period and first appeared in Philadelphia and New York. It would spread all over the nation during the following few years. In 1833, it made its way to Mexico and Cuba in Latin America.

Before it finally died down in about 1851, the pandemic would reappear in many nations for nearly 20 years.

Causes Of Cholera

Cholera infection is caused by  Vibrio cholerae. The bacteria that causes the disease creates a toxin in the small intestine, which is what causes its fatal effects. The toxin makes the body leak massive volumes of water, which results in diarrhoea and a quick loss of fluids and salts (electrolytes), as well as diarrhoea.

Cholera bacteria might not always result in illness in people who are exposed to it, yet these bacteria are still passed in faeces and can contaminate food and water supplies.

The primary method of transmission of cholera is through contaminated water sources.

• Surface or well water may contain the bacteria. Public wells that have been contaminated frequently cause widespread cholera epidemics. Risks are particularly high for those who live in crowded areas without adequate sanitation.
• Seafood. It is possible to become infected with cholera by consuming some types of raw or undercooked seafood, particularly shellfish.
• Produce that is raw. In cholera-endemic regions, raw, unpeeled fruits and vegetables are a common source of cholera infection. Produce in the field can become contaminated in underdeveloped nations by fertilisers made of uncomposted manure or irrigation water that contains raw sewage.
• Grains. For several hours at room temperature, infected grains like rice and millet can produce cholera bacteria in areas where the disease is common.

Symptoms Of Cholera

Most cholera cases that result in symptoms cause mild to severe diarrhoea, which is frequently difficult to distinguish from diarrhoea brought on by other conditions. Others experience more severe cholera symptoms, typically within a few days after infection.

Cholera infection symptoms can include:

• Diarrhea. One litre of fluid per hour can be dangerously lost due to the fast onset of diarrhoea caused by cholera. Cholera-related diarrhoea frequently has a light, milky look and resembles water that has been rinsed off the rice.
• Vomiting and Nauseous. Particularly in the initial stages of cholera, vomiting may last for hours.
• Dehydration. Hours after the first signs of cholera appears we can find Mild to severe dehydration in patients affected with cholera. A 10% or greater reduction in body weight is a sign of severe dehydration.
  • Dehydration from cholera can cause irritation, weariness, sunken eyes, a dry mouth, intense thirst, dry, shrivelled skin that takes a long time to recover after being squeezed, little to no urination, low blood pressure, and sunken eyes.
  • Dehydration can cause a rapid loss of blood minerals that keep the fluid balance in your body in control. Thus leading to electrolyte imbalance.Electrolyte imbalance- Serious symptoms and indicators like the following can result from an electrolyte imbalance:
• Muscular Cramps- These come from salts like sodium, chloride, and potassium losing salts quickly.
• Shock- This is among the most severe side effects of dehydration. It happens when insufficient blood volume results in a drop in blood pressure and a reduction in the amount of oxygen in your body. Severe hypovolemic shock has a five-minute fatality rate if untreated.

Types of Carriers

1. Incubatory Carriers: Shedding infectious agents during the incubation period.
2. Convalescent Carriers: Shedding infectious agents during the recovery period.
3. Contact Carriers: Shedding infectious agents that develop after coming in contact with the case.
4. Chronic Carriers: Shedding infectious agents for more than 3 months.

Risk Factors Of Cholera

Cholera can affect anyone, but certain things may make it more likely. These risk factors also raise your chance of developing a severe case:

• Unclean conditions. Places with poor sanitation and contaminated water have cholera.
• Sick members of Family Members. You have a higher risk if you are in close contact with people who are infected with cholera
• Low Stomach Acid Levels. The cholera bacteria cannot survive in conditions that are highly acidic.
• O Blood Type. Serious sickness is more likely to affect those with type O blood. This might be because type O blood has a greater sensitivity to CTX than other blood types.
• Eating Shellfish Uncooked. There is a higher risk of developing cholera if you consume shellfish from waters that have cholera bacteria present.
• But even in areas where cholera is endemic, the risk of infection is minimal if you follow good food safety procedures or take preventive steps.

Diagnosis Of Cholera

Diagnosis of cholera can be done with the help of the following methods:

• Stool collection and transportation- Mc cartney bottles are used for the transport of stool. Transport holding media is Venkatraman Ramakrishna (VR) media
• Rectal Swabs are transported in Alkaline Peptone water and Cary Blair media is used.
• Culture Method:
  • Enrichment: Inoculation onto peptone water tellurite media
  • Hanging drop preparation-  Demonstrates scintillating movements
  • Darkfield illumination: Shooting stars in the dark sky appearance can be seen.
• Serological tests

Treatment Of Cholera

Treatment of cholera includes:

• Isolation of patient till 2-3 negative stool reports
• Cholera is a notifiable disease
• ORS + zinc
• Antibiotics as per culture report: 
  • Doxycycline
  • Tetracycline
  • Fluoroquinolone
• For children, Erythromycin is used
• For pregnant women  Erythromycin or azithromycin can be used.

Immunization Of Cholera

• Parental vaccine- it is a  heat-killed
• Oral vaccines: 
  • Dukoral: For O1 type. Gastric buffer is used as it contains cholera toxin B subunit. 2 doses 1 to 6 weeks apart. For children, 3 doses are given 1 to 6 weeks apart. It is not given to Children of less than 2 years of age.
  • Sanchol and mORCVAX- Only oral suspensions are given no gastric buffer is used. 2 doses are given  2 weeks apart. For O1 and O139 they are not given to children less than  1 year old.
  • The newly invented vaccine is EUVICHOL

Prevention Of Cholera

Chances of getting cholera can be prevented with the help of the following methods:

• Wash your hands.
• When cooking or brushing your teeth, always use bottled or boiling water. If you can't boil the water, treat it with a chlorine or bleach agent and stay away from dairy.
• Avoid raw shellfish and the majority of other raw foods.
• Only consume raw, easily peeled produce.
• Consult a doctor if, after visiting a region with a high cholera incidence, you continue to experience severe diarrhoea.

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