Pathogens

Vibrio cholerae – Infection, Transmission & Diseases

Vibrio cholerae

Vibrio cholerae is a bacterium of the genus Vibrios . The pathogen can cause the infectious disease cholera .

What is Vibrio cholerae?

Vibrios are gram-negative bacteria. This means that they can be stained red in the Gram stain. In contrast to gram-positive bacteria, gram-negative bacteria have no other cell wall apart from the thin, single-layered shell made of murein.

Vibrios appear as curved rods. They are facultatively anaerobic, meaning they can survive both with and without oxygen . Two types of vibrios are human pathogens. In addition to the bacterium Vibrio parahaemolyticus , this includes the pathogen Vibrio cholerae.

The species Vibrio cholerae includes different strains of bacteria. Not all of these bacterial strains are human pathogens. Vibrio cholerae only becomes pathogenic when so-called bacteriophages penetrate the bacteria. Bacteriophages are different types of viruses that use bacteria as host cells.

Like the other members of the Vibrio genus, Vibrio cholerae can move using a single flagella. The flagella is at the end of the bacterial cell.

Occurrence, Distribution & Properties

The bacterium Vibrio cholerae belongs to the aquatic bacteria. These live in the water. The bacterium is found in both seawater and freshwater. Brackish and coastal waters in particular can be contaminated with Vibrio cholerae. Distribution areas are India and Central Africa. The contaminated water is also the main transmission route for cholera. Above all, untreated or insufficiently treated drinking water is an important source of infection.

But the pathogen cannot only be transmitted by drinking the water. Food that has come into contact with water can also transmit the bacterium. In the endemic areas, freshly washed fruit is often contaminated with cholera pathogens. Vegetable foods often come into contact with Vibrio cholerae in the field. Fecal matter applied as fertilizer is often contaminated with vibrios and acts as a transmission medium.

However, infections occur much more frequently through the consumption of food from the sea. Mussels and other seafood in endemic areas are often contaminated with cholera bacteria.

People suffering from cholera excrete the pathogen in their stool . The pathogen can also be detected in the vomit or in the juice of the small intestine . Even a few weeks after the symptoms have subsided, pathogens are often still found in the stool. However, permanent shedding is rather rare with Vibrio cholerae.

Diseases & Ailments

Vibrio cholerae is the causative agent of cholera. The bacteria release an exotoxin. Since this poison mainly develops its effect in the gastrointestinal tract , it is also referred to as an enterotoxin. The cholera toxin inhibits the GTPase activity of a specific protein , so that at the end of a chain of reactions there is ultimately an excess of cAMP.

CAMP, the cyclic adenosine monophosphate, is a so-called second messenger, which is used for signal transduction within the cell . Due to the excess of cAMP, certain membrane channels within the intestinal wall become more active. On the one hand, this means that more chloride channels are built into the membrane of the cells . In addition, there is a loss of sodium. The connections between the epithelial cells of the intestinal wall become more permeable, resulting in a loss of electrolytes and water. This results in severe diarrhea , which can be accompanied by water losses of up to one liter per hour. Many potassium and hydrogen carbonate ions are lost with the water.

Although the cholera toxin causes the typical symptoms of cholera, cholera only breaks out in around 15 percent of all cases after infection with the pathogen. The incubation period is two to three days. Thereafter, cholera typically progresses through three stages. The first stage begins with vomiting diarrhea. The stool is very thin and interspersed with mucus flakes from the intestinal mucosa. This gives the diarrhea a rice-water-like appearance. Diarrhea is rarely accompanied by pain or cramps in the stomach and intestines.

The second stage is characterized by severe dehydration due to fluid loss from diarrhea. This stage is also known as the desiccation stage. The low temperature of the patients is striking. A conspicuous facial expression develops with sunken cheeks and a pointed nose . Skin folds that are lifted with the fingers remain due to the exsiccosis. Hoarseness may develop as a result of dehydration . The resulting hoarse voice is called vox cholera in medical jargon. The wrinkled hands, on the other hand, are known as laundress hands.

In the third stage there are general body reactions. The patients are dazed and confused. You develop a rash . Complications such as pneumonia or inflammation of the parotid gland can also occur. If the pathogens spread in the blood , blood poisoning (sepsis) can develop, which often leads to coma or death.

An initial suspected diagnosis can usually be made based on the typical clinical symptoms. If cholera is suspected, the doctor creates a stool culture and examines the stool under a microscope. However, a definitive diagnosis can only be made in the laboratory using an antiserum.

Antibiotic therapy is only given in severe cases of cholera . The most important therapeutic measure is the intake of sugar, salts and liquid. To avoid the inflamed gastrointestinal tract, the doctor administers the substances intravenously. The World Health Organization also recommends oral administration of salt and sugar solution in water. With hydration and the use of antibiotics, the mortality rate from cholera has been significantly reduced.

Lisa Newlon
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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.