by Dr. Yogandree Ramsamy

Introduction

Cholera is an acute diarrhoeal infection caused by ingestion of food or water contaminated with the bacterium Vibrio cholerae¹. Outbreaks of Cholera generally occur in areas of the developing world, associated with poor water, sanitation and hygiene.

Aetiology

Toxigenic strains of V. cholerae causes acute fulminant gastroenteritis. V. cholerae is a highly motile, comma-shaped gram-negative bacteria with a single polar flagellum.

There are many serogroups of V. cholerae that include pathogenic and non-pathogenic strains. Until recently, the disease was caused by only 2 of these serotypes, Inaba and Ogawa, and 2 biotypes, classical and El Tor, of toxigenic serogroup O1 however in 1992, serogroup O139, or Bengal, emerged as another epidemic variant of V. cholerae².

Who is at risk of getting cholera?

Those who do not have access to piped safe water and improved sanitation are at risk of getting cholera especially in vulnerable communities affected by natural disasters, war, and famines³.

Symptoms of Cholera

Cholera causes severe acute watery diarrhoea. Incubation period varies between 12 hours and 5 days for an individual to show symptoms following ingestion of contaminated food or water⁴.

Cholera affects both children and adults. Most people infected with V. cholerae have mild symptoms or do not develop any symptoms at all, however bacteria are present in their faeces for 1 – 10 days after infection and are shed back into the environment, potentially infecting other people.

The majority who are symptomatic have mild or moderate symptoms, while a minority develop acute watery diarrhoea with severe dehydration which can be fatal if left untreated.

Symptoms include³:

1. Sudden onset diarrhoea which is profuse, painless and watery, with flecks of mucus in the stool (“rice water” stools).
2. Vomiting may occur, usually early in the illness.
3. Children may develop a fever.
4. Rapid dehydration.

Diagnosis

Cholera cases are detected based on clinical suspicion in patients who present with severe acute watery diarrhoea.

The identification of V. cholerae in stool samples from affected patients confirms the diagnosis of Cholera. Samples are submitted to a laboratory for confirmation by stool culture or PCR¹.

How is cholera treated?

Rehydration is the cornerstone of treatment and is lifesaving. Mild cases can be managed outside the hospital setting with oral rehydration therapy (ORT).

Moderate and severely ill patients require hospitalization for intravenous fluid rehydration. Antibiotics are recommended for patients with moderate or severe dehydration. The antibiotic of choice currently recommended is Ciprofloxacin.

Paediatric dose: 20 mg/kg (max 1g) po stat. Adult dose: 1g po stat. Zinc supplementation for children <5 years old is also recommended. The prescription of anti-motility drugs (e.g. loperamide) is not recommended. Isolate patient and apply contact as well as hand hygiene precautions³.

How can you avoid getting cholera?

Refer to the NICD infographic on the reconstitution of safe drinking water and hygiene precautions₅.

Cholera Prevention Drink and use safe water. Wash hands regularly with soap and safe water. To render water safe add 5mls (1 teaspoon) of household bleach to 20 – 25 litres of water. Boiling the water is also effective however there is a potential for microbial re-growth if boiled water is stored beyond 1 – 2 days.

References

1. https://www.who.int/news-room/fact-sheets/detail/cholera
2. Ojeda Rodriguez JA, Kahwaji CI. Vibrio cholerae Infection. Treasure Island (FL): StatPearls 2023 – Available from: https://www.ncbi.nlm.nih.gov/books/NBK526099/
3. https://www.nicd.ac.za/diseases-a-z-index/cholera/
4. The incubation period of cholera: a systematic review. https://www.ncbi.nlm.nih.gov/pubmed/23201968 Azman AS, Rudolph KE, Cummings DA, Lessler J. J Infect. 2013;66(5):432-8. doi: 10.1016/j.jinf.2012.11.013. PubMed PMID: 23201968; PubMed Central PMCID: PMC3677557
5. https://www.nicd.ac.za/wp-content/uploads/2023/05/A4-Cholera-Poster.pdf