Cholera is an acute infection of the small intestine caused by the bacterium Vibrio cholerae. It is characterized by severe diarrhea, which can lead to rapid and extreme loss of body fluids. Cholera spreads through food and water contaminated with Vibrio cholerae, often from feces. The disease has frequently reached epidemic levels in sub-Saharan Africa and South Asia, particularly in India and Bangladesh. Over the past two centuries, there have been seven pandemics (global outbreaks) of cholera.
Prompt rehydration therapy is the cornerstone of cholera management. Meanwhile, the World Health Organization (WHO) has coordinated a network of partners to help several countries develop national cholera control strategies. The global roadmap for cholera control focuses on stopping transmission in cholera hotspots through vaccination and improved water, sanitation, and hygiene, aiming to reduce cholera deaths by 90% and eliminate local transmission in at least 20 countries by 2030.
Cholera continues to be a major health issue in poor countries, especially in areas with inadequate water, sanitation, and hygiene services (WASH). It remains a frequent cause of outbreaks globally, particularly in these regions.
Causes and Symptoms of Cholera
Cholera is primarily caused by the bacterium Vibrio cholerae, which infects the intestines and leads to symptoms like severe diarrhea and dehydration. The transmission of cholera commonly occurs through the consumption of contaminated water or food. When an infected individual excretes bacteria-laden stool into a water source, such as a river or well, and others consume water from that source, the disease can spread rapidly. Once V. cholerae enters the body through contaminated food or water, it multiplies in the small intestine, prompting the intestines to secrete fluid and causing diarrhea. This underscores the critical importance of clean water sources and proper sanitation to prevent cholera transmission.
Symptoms of Cholera
Cholera is marked by the sudden onset of profuse, watery diarrhea, typically after an incubation period of 12 to 28 hours. The stools, often described as "rice water" stools, may contain flecks of mucus. Diarrhea is frequently accompanied by vomiting, leading to rapid dehydration. Patients may experience intense thirst, a dry tongue, lowered blood pressure, a faint pulse, and severe muscle cramps. Their eyes may appear hollow and sunken, and their skin may wrinkle, resembling "washerwoman's hands." Children may also suffer from fever, lethargy, and seizures due to extreme dehydration. The disease usually runs its course within 2 to 7 days. If you suspect cholera, seek medical care promptly to prevent severe dehydration and complications.
t cholera, seek medical care promptly to prevent severe dehydration and complications.
Diarrhea and vomiting from cholera can cause significant loss of:
- Fluids
- Electrolytes
- Sodium
- Potassium
When these substances are depleted, dehydration can lead to:
- Dry mucous membranes in the eyes, nose, and mouth
- Rapid heart rate
- Hypokalemia (low potassium levels in the blood)
- Low blood pressure
- Loss of skin elasticity
Untreated, severe dehydration from cholera can result in:
- Shock
- Coma
- Kidney failure
- Death
History of Cholera
Cholera is caused by infection with the V. cholerae bacteria, which were discovered in 1883. The German bacteriologist Robert Koch (1843–1910) studied the disease during an epidemic in Egypt. He identified the bacteria in the intestines of those who had died from cholera but initially could neither isolate the organism nor infect animals with it. Later that year, Koch succeeded in isolating the bacteria in India. He found that they thrived in damp, dirty linen, moist earth, and the stools of patients with the disease.
V. cholerae bacteria live in shallow, salty water on microscopic crustaceans. They can also form biofilm colonies on surfaces such as water, plants, stones, shells, and even the eggs of midges, which serve as a reservoir for the bacteria. Toxic strains of *V. cholerae* produce a toxin that triggers violent diarrhea in humans. When these bacteria enter human-populated areas, they can rapidly cause severe epidemics. Weather changes, population loss, and improved sanitation can all end an outbreak.
Risk Factors
Everyone is susceptible to cholera except infants who gain immunity from nursing mothers who have previously had cholera. However, certain factors increase vulnerability to the disease or the likelihood of severe symptoms. These risk factors include:
- Poor sanitary conditions: Cholera is more likely to occur in unsanitary environments where maintaining safe water or hygiene practices is difficult. Such conditions are common in refugee camps, impoverished areas, and regions affected by famine, war, or natural disasters.
- Reduced or nonexistent stomach acid V. cholerae cannot survive in an acidic environment, and ordinary stomach acid often protects against infection. People with low levels of stomach acid—such as children, older adults, and those taking antacids, H-2 blockers, or proton pump inhibitors—are at greater risk of cholera.
- Household exposure: Living with someone who has cholera increases the risk of contracting the disease.
- Type O blood: For reasons not entirely understood, people with type O blood are twice as likely to develop cholera compared to those with other blood types.
- Raw or undercooked shellfish: Although industrialized nations no longer experience large-scale cholera outbreaks, eating shellfish from waters known to harbor the bacteria significantly increases risk.
- Vegetables grown with contaminated water: Consuming vegetables irrigated with water containing human waste can lead to cholera infection.
- Raw or undercooked fish and seafood: These are also potential sources of cholera.
Prevention of Cholera
To prevent cholera, take the following precautions:
- Avoid tap water, water fountains, and ice cubes. This includes water used for drinking, washing dishes, preparing food, and brushing teeth.
- Do not consume raw food.
- Drink only safe water, such as bottled water or water you have boiled or disinfected yourself. Use bottled water even for brushing your teeth. Hot beverages are generally safe, as are canned or bottled drinks, but wipe the outside before opening them. Avoid adding ice to drinks unless you made it with safe water.
- Eat prepackaged foods or ensure other foods are freshly cooked and served hot.
- Consider disinfecting your water: boil it for at least one minute, add half an iodine tablet or two drops of household bleach per liter, or use chlorine tablets.
- Wash fruits and vegetables with clean water.
- Wash your hands with soap and clean water, especially before handling food and after using the bathroom. If soap and clean water are unavailable, use hand sanitizer with at least 60% alcohol.
- Consume only food that is completely cooked and hot, and avoid street food if possible. If buying from a street vendor, ensure the food is cooked in your presence and served hot.
- Avoid sushi and raw or improperly cooked fish and seafood.
- Seek medical help if you suspect cholera or experience symptoms like severe diarrhea and vomiting.
- Consider getting vaccinated if traveling to regions where cholera is common to protect against infection.
- Stick to fruits and vegetables that can be peeled, such as bananas, oranges, and avocados, and avoid salads and fruits that can't be peeled, like grapes and berries.
Community education also plays a crucial role in preventing cholera outbreaks. This can be achieved by:
1. Awareness: Raising awareness and educating communities about cholera transmission modes, such as contaminated water and poor sanitation.
2. Hygiene Practices: Teaching proper handwashing, safe food handling, sanitation, and the link between hygiene and prevention.
3. Water Sources: Educating communities to identify safe water sources and avoid contaminated ones, making boiling or treating water a routine practice.
4. Vaccination: Encouraging participation in vaccination campaigns through education about oral cholera vaccines. Community-wide immunity reduces overall risk.
Cholera Diagnosis
Diagnosing cholera involves testing a stool sample. A healthcare provider will collect a stool sample, often by having the patient defecate into a collection cup or bag. In some cases, a swab is inserted into the rectum. The sample is sent to a laboratory, where experts examine it under a microscope to identify V. cholerae. Some regions where cholera is more common have access to a "dipstick" tool that can rapidly test a stool sample.
Treatment of Cholera
The primary treatment for cholera involves replacing lost fluids and salts through oral or intravenous rehydration with an alkaline solution of sodium chloride. Oral rehydration solutions (ORS) consist of a measured mixture of glucose, sodium chloride, potassium chloride, and trisodium. The mixture can be prepackaged and administered by non-medical personnel, allowing cholera to be treated even under challenging conditions. ORS is generally sufficient for treating all but the most severely dehydrated patients, who require intravenous rehydration.
Administering antibiotics, such as tetracycline, during the first day of treatment usually shortens the period of diarrhea and decreases the amount of fluid replacement required. It is also important for patients to resume eating as soon as possible to avoid malnutrition. While self-medication is not advisable, these tips can help prevent cholera.
Hydration remains the cornerstone of cholera treatment. Depending on the severity of diarrhea, treatment may involve oral or intravenous fluids to replace lost liquids. While antibiotics are not typically part of emergency treatment for mild cases, they can reduce the duration of diarrhea by half and decrease the excretion of the bacteria, helping to prevent the spread of the disease.
