Measures for Cholera Diagnosis – How the Disease is Detected

Doctors usually carry out cholera diagnosis measures clinically and start treatment immediately without waiting for a laboratory confirmation due to the deadly nature of the illness.

cholera diagnosis

Cholera diagnosis involves isolation and examination of the cholera bacteria from a stool sample of the patient.

However, a cholera case has to be confirmed by isolating the causative agent Vibrio cholerae from the stool (feces) in a microbiology laboratory. A detailed history of the patient is always helpful during the initial stages of the diagnostic procedure, and doctors are likely to provide a questionnaire to investigate:

  • The source of infection
  • Contact history
  • Chemoprophylaxis (treatment) history
  • Immunization (vaccine) history

The Steps Involved In Cholera Diagnosis

Step 1: The Sample Is First Collected

Feces or rectal swab (a cotton swab inserted into the rectum, rotated gently, and removed) are collected during the early stages of the disease before administering any antibiotics. Blood may also be collected for the detection of antibodies. This happens when you go for medical advice with cholera symptoms.

Step 2: The Sample Is Transported

Samples collected are immediately transported to the laboratory. Cary Blair transportation media is used to maintain the bacterium in its living state.

Laboratory cholera diagnosis is based on:

  • Macroscopic examination of sample
  • Microscopic examination
  • Bacterial culture identification
  • Serogrouping
  • Serology
  • Rapid tests

Step 3: Macroscopic Examination Is Carried Out

Once the laboratory personnel receive the sample, macroscopic examination of the stool is carried out.

The stool of cholera patients has a characteristic ‘rice water’ appearance.

Step 4: Direct Microscopic Examination Is Carried Out

The stool sample is later stained and observed under the microscope for detecting the bacteria that cause cholera.

  • Staining: The vibrio bacteria are comma shaped and stain pink (negative) under the Gram staining technique (a widely used staining technique for bacterial identification).
  • Motility Tests: Vibrio has a characteristic ‘darting motility’ which can be observed using a ‘hanging drop preparation’, where a drop of the sample is placed in a specially designed inverted microscopic slide and later observed under microscope. Dark field microscopy is also used for observing vibrio motility.

Step 5: The Bacteria Is Cultured

Even though direct microscopy offers a quick presumptive diagnosis of V cholerae, the diagnosis is confirmed by isolating the bacteria in various culture media.

Enrichment media such as alkaline peptone water at pH 8.6 or Monsur’s taurocholate tellurite peptone water at pH 9.2 are used for enriching the bacteria. In simple terms, sometimes the bacteria can’t be identified when they are fewer in number. These components will help them grow and spread, making identification easier.

Even substances like TCBS Agar are used to selectively allow the growth of Vibrio cholera among other intestinal bacteria that may be present in the stool sample. The bacterium forms flat, 2–3-mm-diameter, yellow colonies after 18 hours of incubation.

Step 6: V Cholerae Is Identified

Once the bacterium grows in the culture medium, it is identified and confirmed by:

1. Microscopy

2. Motility test

3. Biochemical identification

4. Serogrouping

Once the bacterium is isolated and identified, antibiotic susceptibility of the particular isolate can be tested by antibiotic sensitivity tests.

Various rapid test kits such as the Rapid Dip-stick Test are also available commercially, but are used only during an epidemic. This helps in confirming the cholera diagnosis quickly, decreasing the death rate right at the start of the outbreak. The major disadvantages of such tests are that an isolate will not be available for serogrouping or for antibiotic susceptibility testing. For this reason, isolating and identifying the bacteria is still the gold standard for cholera diagnosis and confirmation.

The Major Causes of Cholera – How Cholera Starts and Spreads

Cholera, a disease that is caused by Vibrio cholera (bacteria), is often referred to as the ‘disease of the poor’ due to its occurrence in underdeveloped and developing countries of the world. The causes of cholera are often attributed to poor sanitation and improper water treatment facilities, which are common mainly in developing countries.

The Causes Of Cholera – The Causative Organism

Cholera in humans is mainly caused by the bacterium Vibrio cholera, which belongs to the genus Enterobacteriaceae. They are slightly comma shaped, motile (moving) organisms.

The Causes Of Cholera Explained – How It Spreads

The causes and spread of cholera can be explained in three key points:

  • Reservoir of infection
  • Sources of infection
  • Mode of transmission 

Reservoir Of Infection

Humans and water are the two main reservoirs (or carriers) of cholera and the virus constantly cycles between the environment and the human body.

The primary habitat of this salt water organism is the marine ecosystem, where it is often associated with zooplanktons. An outbreak of cholera is often marked by a zooplankton bloom, and this is why cholera is considered to be a zoonotic disease (passed from animals).

The cholera bacterium is usually harbored in the environment by:

  • Brackish water
  • Coastal waters (attached to tiny crustaceans called copepods)
  • Ponds and estuaries
  • Zooplanktons and shellfish (especially oysters)

Humans can serve as a reservoir for the cholera bacterium when they contract the disease or act as carriers.

Carriers harbor the bacterium in their intestines and shed it out through their feces, sometimes for prolonged periods, without showing any evidence of the disease. Even though the bacterium’s carrier state is short lived, it plays a major role in spreading the disease widely.

causes of cholera

The intake of infected food and water are the main causes of cholera

Sources Of Infection

To understand the causes of cholera, you should be able to identify the source of infection.

Food items and water-based drinks that have been contaminated with the feces of cholera-infected individuals serve as major sources of infection. For this very reason, cholera is also known as ‘fecal disease’.

The following are some of the cases that rank among the causes of cholera.

  • When untreated diarrheal discharge is mixed with drinking water
  • When the soil is contaminated with cholera-infected feces
  • Raw or undercooked shellfishes that carry the bacterium
  • Fruits and vegetables that are washed in contaminated water
  • When manure fertilizers or irrigation water get contaminated with sewage while farming
  • Ice made from contaminated water

Mode Of Transmission

Cholera is transmitted through infected water or food, and no direct human to human transmission has been indicated. For this reason, casual contact with infected individuals will not pose a threat. Methods of cholera prevention can be undertaken to prevent getting the infection.

Close to 100 million organisms must be ingested in order to initiate the infection.

Once inside the stomach, the bacteria produces the cholera toxin, which interrupts the normal flow of sodium and chloride in the body and increases the release of water from the intestinal cells. This disruption in the body’s functioning causes watery diarrhea that is rich in electrolytes. The bacteria are also shed through the feces.

The Causes Of Cholera – Environmental And Host Risk Factors

When it comes to the causes of cholera, the following environmental conditions play a major role.

  • Crowded living conditions
  • Poor sanitation and personal hygiene
  • Situations of war, famine, or natural calamities
  • Military refugee camps
  • Improper water treatment facilities with unsafe drinking water
  • Improper disposal of faeces
  • Poor countries or slums without basic infrastructure
  • Global warming (increase the susceptibility of infection)

Host factors that can increase the susceptibility of infection are:

  • Malnutrition
  • Gastric surgery
  • Helicobacter pylori infection
  • The use of H2 blockers in ulcer disease
  • Type O blood group (unknown cause)
  • Vagotomy, where the vagus nerve is surgically removed to reduce acid secretion in the stomach

Cholera is prevalent and confined to certain regions including Southeast Asia (and India), Sub-Saharan Africa, and Latin America. It can be introduced to any area by a person who has contracted the disease after travelling to such cholera endemic areas. In case you feel you have any of the cholera symptoms, it is of extreme importance to reach out to a doctor to get a proper cholera diagnosis. With proper sanitary measures, the causes of cholera can be combated against.

Cholera Facts for Dummies – Some Basics About The Disease

Cholera is a highly contagious, rapidly progressing diarrheal illness caused by a bacterium named Vibrio cholerae. Even though cholera presents itself in a mild form, without any symptoms in a majority of cases, it may turn severe in 20% of the cases and can even prove to be fatal – bringing about the need for you to be aware about common cholera facts.

Humans and water are the major reservoirs of the cholera bacterium, and Vibrio cholerae can live in brackish waters, estuaries, ponds, and even coastal waters.

cholera facts

One of the primary cholera facts is that the disease is caused by the bacterium, Vibrio Cholerae

Cholera Facts – Understanding The Disease

Cholera is acquired through the ingestion of food or water that’s contaminated with the bacteria. The causes of cholera are:

  • Untreated diarrheal discharge that gets into drinking water
  • Raw or undercooked shellfishes
  • Fruits and vegetables that have been exposed to contaminated water
  • Manure fertilizers or irrigation water contaminated with sewage for farming use
  • Ice made from contaminated water

Once inside the human body, cholera presents as profuse and painless watery diarrhea with a rice-water appearance. Other cholera symptoms include vomiting and muscle cramps, after an incubation period of a few hours to five days.

The point of learning such cholera facts is because you should immediately report the symptoms to the doctor, regardless of how mild the symptom is. Signs of dehydration, including dry mouth, dry skin, excessive thirst, low urine output, lack of tears, and extreme drowsiness or lethargy are common cholera symptoms.

Sleepiness, rapid pulse rate or heart beat, and or glassy or sunken eyes are also symptoms that should be reported. It is a well established cholera fact that the rapid loss of fluids and electrolyte can cause severe dehydration and death in a matter of hours, without medical attention. Once you feel that your symptoms resemble those of the infection’s, it is important to get a cholera diagnosis immediately.

Cholera Facts – The High Risk Areas

The cholera infection is often reported in crowded areas with poor sanitation or personal hygiene. Outbreaks are common in sites of war, famine, and natural calamities, military refugee camps, and improper water treatment facilities.

Drinking unsafe water, failing to properly dispose feces, and travelling to cholera affected areas without taking adequate precautions can lead to the condition. Cholera outbreaks are common in Southeast Asia, Africa, and Latin America. The disease is rare in developed countries, owing to their improved water treatment facilities and sanitation practices.

Cholera Facts To Help You Avoid The Disease

Cholera can be avoided if proper sanitary measures are implemented. The Center For Disease Control and Prevention recommends five basic cholera facts for prevention:

  • Drink and use safe and boiled water (Boil the water at 100 °C at least for a minute)
  • Wash your hands often with soap and safe water
  • Use latrines or bury faeces, and do not defecate in any body of water
  • Cook food well, keep it covered, eat it hot, and peel fruits and vegetables only while eating
  • Keep your house clean, especially the kitchen, washing area, and the restroom

Methods of cholera prevention must be undertaken to prevent contracting the disease.

Cholera Facts About Treatment Options

The cholera bacterium is isolated and identified through a stool or blood test in any microbiology laboratory. The aim of cholera treatment is to replace lost fluids and electrolytes (salts) through oral rehydration therapy, which is highly effective. In severe cases fluid should be administered intravenously.

Antibiotics like doxycycline and tetracycline are used to reduce the symptoms and duration of the illness. Even though vaccines are available for cholera, these are not recommended by the World Health Organization due to the short duration of protection, high incidence of adverse reactions, and limited availability. Prevention is always better than cure, and by just knowing some basic cholera facts, you can avoid the disease and stay healthy.

Five Tips for Cholera Prevention – How to Avoid the Disease

Cholera prevention gets easier when proper sanitary conditions are maintained, and this is one of the main reasons why cholera is extremely rare in developed countries – due to the fact that they have advanced water treatment facilities and follow good sanitary practices. This disease can be prevented on a large scale by analyzing the causes of cholera and cholera facts.

The Basics Of Cholera Prevention

The following cholera prevention steps will help you stop the disease at any stage in its transmission cycle:

  • Proper disposal of sewage
  • Sterilization of contaminated infected materials (clothes, bedding)
  • Use of disinfectants like chlorine beach
  • Warning boards over contaminated water sources and directions on the water treatment strategies (by chlorination and boiling)
  • Water purification measures (chlorination, boiling, ozone treatment, UV sterilization, filtration)

The CDC Guidelines On Cholera Prevention

The Center For Disease Control And Prevention (CDC) recommends five basic cholera prevention measures for people to follow, and these have been elaborated below.

Drink and Use Safe Water

Always use safe water to stay healthy. You should use:

  • Bottled water with unbroken seals
  • Canned/bottled beverages with unbroken seals
  • Safe water for ice preparation
  • Safe water to wash and prepare food
  • Safe water to brush teeth

As far as possible, try and avoid:

  • Piped water sources
  • Drinks sold in cups or bags
  • Ice made of water from unknown sources
  • Food or beverages from street vendors
  • Unpasteurized milk and milk products

You can make the available water safe through these cholera prevention measures.

  • Boil the water at 100 °C for at least a minute
  • Use chlorine treatment (or house hold bleach), and add two drops of household bleach for every liter of water, 30 minutes before drinking
  • Store water in a clean and covered container

Always Wash your Hands Thoroughly

Wash your hands often with soap and water, before eating food, feeding food to children, or preparing food and after using toilets and meeting diarrheal patients.

Scrubbing your hands with ash or sand might work, in cases when soap is not available.

cholera prevention

For effective cholera prevention, wash your hands regularly

Dispose Feces Properly

When it comes to cholera prevention measures, this is very important. The proper disposal of feces can be taken care of through the following pointers.

  • Always use latrines or other sanitary systems like chemical toilets
  • Wash your hands with soap and water after defecating
  • Clean the toilet and other areas that are contaminated with feces with 1:9 parts household bleach in water
  • Never defecate in any body of water, as this can trigger the disease

If you’re camping in another country or your own, and don’t have access to a toilet:

  • Defecate 30 meters away from the nearest water body
  • Bury the faeces with sand once done
  • Dig temporary pit toilets that are half a meter deep and located away from the water body

Keep Your Food Covered And Safe

Another important cholera prevention step is to cook your food well, so that there is no risk of catching an infection.

  • Always boil food items (like vegetables) before cooking them, if possible
  • Cook the foods well, especially shellfish like crabs and crayfishes, until the food is piping hot
  • Keep the food covered once done, and serve it hot
  • Peel fruits and vegetables before eating them, and avoid other raw food items

Clean Up The Washing Areas

This is another important cholera prevention step that you should take.

  • Clean your kitchenware and the cooking area with soap and water
  • Regularly clean the bathroom and washing area (laundry)
  • Always wash and bathe 30 meters away from drinking water sources

In addition to the above mentioned cholera prevention strategy, there are preventive vaccine recommendations for the disease too. Two commercially available oral vaccines for cholera are Shanchol (for children under 5 years of age) and Dukoral. These vaccines provide protection against the disease for just two years. The World Health Organization (WHO) recommends the use of cholera vaccines along with available preventive measures.

Cholera Symptoms Explained – Signs You Should Watch Out For

It’s extremely vital to watch out for cholera symptoms, as a delayed diagnosis can often prove to be fatal, due to the nature of the disease.

Cholera, caused by a bacterium, is a highly contagious diarrheal disease that begins and progresses rapidly. Once contracted, mainly through the consumption of contaminated water or food, clinical cholera symptoms appear within a few hours to 5 days.

Cholera presents itself as mild or asymptomatic in 80 – 90% of the cases, but in 20% of the cases, it can become severe and, if not treated promptly, can even lead to the death of the individual within hours of onset.

Cholera Symptoms You Should Watch Out For

The primary cholera symptoms include the following:

  • Diarrhea and vomiting
  • Dehydration
  • Electrolyte Imbalance

Cholera Symptoms #1: Diarrhea And Vomiting

The most strikingly characteristic symptom of cholera is a painless and profusely watery stool that patients pass, often accompanied by a fishy odor. Based on how such stool looks, it is also termed as “rice water stool”.

The stool of affected individuals has a pale, milky, or cloudy appearance due to the presence of flakes of mucus and intestinal epithelial cells. It resembles the water in which rice has been rinsed.

Untreated cholera can lead to water, fluid, and electrolyte loss from the body at the rate of 0.95 liters/hour. The disease leads to the production of 20-30 liters of stool everyday.

Why Do Cholera Patients Lose Fluids?

Diarrhea in patients is caused by the release of the cholera toxin by the bacterium.

This toxin blocks the absorption of sodium and chloride by the intestinal absorptive cells and promotes the secretion of water and chloride, causing watery diarrhea.

Patient may experience other abdominal cholera symptoms like:

  • Stomach pain
  • Abdominal cramps (sudden involuntary painful muscular contraction)
  • Nausea (vomiting sensation)
  • Persistent vomiting
  • Mild fever

Cholera Symptoms #2: Dehydration

Severe dehydration often occurs four to eight hours after the first liquid stool. The patient’s skin may turn bluish grey due to dehydration, a condition termed as blue death”.

cholera symptoms

Dehydration, one of the main cholera symptoms, is manifested by wrinkled skin.

The skin may become wrinkled and non-elastic due to the loss of moisture, resembling the hands of a washer-woman (as per popular depiction). A person experiencing dehydration is likely to sport other such signs:

  • Dry mouth and mucous membrane
  • Dry skin
  • Glassy or sunken eyes
  • Excessive thirst
  • Low urine output
  • Lack of tears
  • Extreme drowsiness or lethargy
  • Sleepiness
  • Rapid pulse/heart beat
  • Arrhythmia/Irregular heart beat
  • Restlessness and irritability

People who present with such cholera symptoms should be immediately moved to a hospital and given proper medical care, as this is a serious development. This will allow them to get a cholera diagnosis.

Cholera Symptoms #3: Electrolyte Imbalance

This is one of the main cholera symptoms. Dehydration leads to the rapid loss of minerals or electrolytes from the blood, causing an electrolyte imbalance.

The rapid loss of salts like sodium, chloride, and potassium can result in muscular cramps too. The glucose concentration in the bloodstream may also decrease (hypoglycemia).

The electrolyte imbalance can cause an excessively acidic condition of the body fluids and tissues, also known as “acidosis”.

Why Is It Important To Look For Cholera Symptoms?

If untreated, cholera can cause a hypovolemic shock – an emergency condition in which rapid fluid and blood loss can bring down the heart’s ability to pump enough blood and oxygen to the body, leading to circulatory collapse, acute renal failure, multi-organ failure, coma, and ultimately death.

HIV patients and malnourished individuals, who sport a weak immune system, face a higher risk of developing complications.

Cholera accounts for 100000 –1,20,000 deaths annually, and only through the proper identification of cholera symptoms and subsequent treatment can this disease be countered. Cholera prevention and causes of cholera should be analysed thoroughly to ensure that you don’t contract the disease.