Cholera is an infectious disease that causes severe watery diarrhea, which can lead to dehydration and even death if untreated.
Cholera is an infection of the small intestine by some strains of the bacterium Vibrio cholerae. It is a serious bacterial disease that usually causes severe diarrhea and dehydration.
The disease is typically spread through contaminated water. In severe cases, immediate treatment is necessary because death can occur within hours. This can happen even if you were healthy before you caught it.
Modern sewage and water treatment have effectively eliminated cholera in most countries. It’s still a problem in countries in Asia, Latin America, Africa, India, and the Middle East.
Countries affected by war, poverty, and natural disasters have the greatest risk for a cholera outbreak. That’s because these conditions tend to force people to live in crowded areas without proper sanitation.
Causative agent
Vibrio cholera, the bacterium that is solely responsible for cholera, is generally found in food or water contaminated by feces from a person who has the infection.
Common sources are:
• Municipal water supplies
• Ice made of municipal water
• Food and drinks sold at street stalls
• Vegetables grown in water contaminated with human waste
• Raw or uncooked fish or seafood caught from waters that are polluted with sewage
When a person eats that contaminated food or drinks the water, the bacteria tend to release a toxin in the intestines that cause severe diarrhoea.
There are fewer chances of you getting affected by cholera simply from casual contact with an infected person.
Symptoms
When someone is infected with cholera bacteria, symptoms can appear in a few hours or as late as 5 days later. Some people have no signs or symptoms, but some cases are severe and can be life-threatening.
Common symptoms of cholera and the dehydration it causes include:
• watery, pale-colored diarrhea, often in large amounts
• nausea and vomiting
• cramps, particularly in the abdomen and legs
• irritability, lack of energy, or unusual sleepiness
• glassy or sunken eyes
• dry mouth and extreme thirst
• dry, shriveled skin
• low urine (pee) output and a lack of tears
• irregular heartbeat (arrhythmia) and low blood pressure
Cholera can cause watery diarrhea and vomiting, making people who have it get dehydrated quickly.
When dehydration is severe, it can cause serious health problems if it's not treated. It can even cause seizures and kidney failure. People who don't get the proper medical treatment may even die.
Diagnosis
A rapid dipstick test is available to determine the presence of V. cholerae. In those samples that test positive, further testing should be done to determine antibiotic resistance.
In epidemic situations, a clinical diagnosis may be made by taking a patient history and doing a brief examination. Treatment is usually started without or before confirmation by laboratory analysis.
Stool and swab samples collected in the acute stage of the disease, before antibiotics have been administered, are the most useful specimens for laboratory diagnosis.
If an epidemic of cholera is suspected, the most common causative agent is V. cholerae O1. If V. cholerae serogroup O1 is not isolated, the laboratory should test for V. cholerae O139. However, if neither of these organisms is isolated, it is necessary to send stool specimens to a reference laboratory.
Infection with V. cholerae O139 should be reported and handled in the same manner as that caused by V. cholerae O1. The associated diarrheal illness should be referred to as cholera and must be reported in the United States.
Treatment
Cholera requires immediate treatment because the disease can cause death within hours.
• Rehydration. The goal is to replace lost fluids and electrolytes using a simple rehydration solution, oral rehydration salts (ORS). The ORS solution is available as a powder that can be made with boiled or bottled water.
Without rehydration, approximately half the people with cholera die. With treatment, fatalities drop to less than 1%.
• Intravenous fluids. Most people with cholera can be helped by oral rehydration alone, but severely dehydrated people might also need intravenous fluids.
• Antibiotics. While not a necessary part of cholera treatment, some antibiotics can reduce cholera-related diarrhea and shorten how long it lasts in severely ill people.
• Zinc supplements. Research has shown that zinc might decrease diarrhea and shorten how long it lasts in children with cholera.
Type of vaccine:
a. Killed oral O1 with whole-cell with Bsubunit
b. Killed oral O1 and O139
Number of doses:
a. Two doses (minimum 1 week and maximum 6 weeks apart). Three doses for children aged 2–5 years (minimum 1 week and maximum 6 weeks apart)
b. Two doses 14 days apart for individuals aged ≥2 year. One booster dose is recommended after 2 years
Contraindications: Hypersensitivity to previous dose
Adverse reactions: Mild gastrointestinal disturbances
Before departure: 2 weeks
Consider for: Travellers at high risk (e.g. emergency/ relief workers)
Special precautions: None
Mortality
The mortality of cholera in untreated patients may reach 50 to 70 percent. Administration of appropriate rehydration therapy can reduce the mortality of severe cholera to less than 0.5 percent .
In areas where cholera is endemic, the mortality risk is increased in children (10 times greater than in adults) .
Although earlier studies had suggested a high risk of fetal death associated with cholera during pregnancy (up to 50 percent during the third trimester), more recent studies have reported a lower, but still elevated, risk (approximately 8 percent)
Prevention
Here are some precautions that canreduce your risk of getting cholera if you are in an area where it is widespread:
• Drink only bottled, boiled, or chemically treated water or carbonated beverages. When using bottled drinks, make sure that the seal has not already been broken.
• Avoid tap water and ice cubes made from tap water.
• If bottled water is not available, you can disinfect water by boiling it for one minute or filtering it, and then adding two drops of household bleach or half of an iodine tablet per liter of water.
• Wash your hands with soap and clean water every time you use the bathroom, and before you eat or prepare food. If soap and water are not available, use an alcohol-based hand cleaner that is at least 60% alcohol.
• Eat foods that are pre-packaged or that are freshly cooked and served hot. Avoid raw and undercooked meats and seafood or unpeeled fruits and vegetables.
• Dispose of feces in a place away from water that is used for drinking or food, especially if you have had cholera.