Cholera is caused by consuming water or food contaminated with the bacterium Vibrio cholerae. Cholera bacteria can also live in brackish and coastal waters. Eating raw shellfish from these waters can also be a source of disease. According to the World Health Organization, there are 1.3 million to 4 million cases and between 21,000 and 143,000 deaths from cholera each year.
There are two main types of cholera outbreaks: those that circulate within countries where outbreaks happen regularly and those that begin spiraling out of control during a crisis, such as a conflict or natural disaster. In war zones, the destruction of water and sanitation infrastructure leads to sewage contamination of the water supply. Natural disasters are becoming more common due to climate change. Floods, for example, pollute drinking water.
Vibrio cholerae is a gram-negative, comma-shaped bacterium. They have a single flagellum and are highly motile. The bacterium possess a somatic O antigen and a flagellar H antigen. The H antigen distinguishes pathogenic from nonpathogenic strains. More than 200 serogroups of V cholerae have been identified, but only the toxigenic strains of V cholera cause cholera. Of those, only serogroups O1 and O139 cause cholera epidemics.
When Vibrio cholerae reach the small intestine, they adhere to epithelial cells, multiply, and secrete toxin. This toxin has an A1 subunit, which activates adenylate cyclase to increase cyclic adenosine monophosphate (cAMP). cAMP inhibits the absorption of sodium and chloride from the microvilli and increases the secretion of chloride and water from the crypt cells, causing profuse, isotonic, watery diarrhea. When the toxin enters the epithelial cells, it alters the electrolyte channels, resulting in endoluminal fluid loss rich in chloride, bicarbonate, sodium, and potassium.
Symptoms usually appear 2-3 days after someone drinks or eats something containing cholera bacteria. Symptoms can show up within a few hours or up to 5 days. The earliest symptom is the onset of painless, large-volume, watery diarrhea. Although initial diarrhea may include fecal material, the classic presentation consists of watery, foul-smelling mucous described as rice-water stools because they appear milky white. Diarrhea may be accompanied by vomiting, leg cramps, and restlessness or irritability. Patients may quickly become dehydrated. If untreated, severe dehydration can lead to renal failure, hypovolemic shock, coma, and death.
Treatment consists of keeping a patient hydrated with rehydration fluids such as Pedialyte. Some patients may require intravenous fluids and antibiotics. If cholera is treated quickly, fewer than 1% of patients die.
Cholera is fairly easy to identify. Patients have distinctive stool that appears yellowish or whitish, resembling rice water. Cases can be confirmed by bacterial culture on thiosulfate-citrate-bile salts-sucrose agar (TCBS). This selective media inhibits the growth of normal bowel flora while allowing growth of Vibrio species.Suspect colonies are identified using a combination of matrix-associated laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry, biochemical tests, carbon source utilization, and nucleic acid sequencing of the 16S ribosomal RNA (rRNA) gene.
Cholera is a nationally reportable disease in the U.S. All isolates should be sent to the CDC through state health department laboratories for cholera toxin and subtyping.
Three oral vaccines are available to prevent cholera in countries where the disease occurs regularly. Gavi, the Vaccine Alliance issued 35 million doses in 2023.
References
Ojeda Rodriguez JA, Hashmi MF, Kahwaji CI. Vibrio cholerae Infection. [Updated 2024 May 1]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK526099/
Montero DA, et al. Vibrio cholerae, classification, pathogenesis, immune response, and trends in vaccine development. Front Med (Lausanne). 2023 May 5;10:1155751. doi: 10.3389/fmed.2023.1155751.
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