Cholera
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Organism
vibrio cholerae (gram negative)
incubation- avg 3 days
Cholera bacterium
Cholera bacterium. Model of cholera bacteria – Smithsonian Museum of Natural History – 2012 – by Tim Evanson. Licensed with CC BY-SA 2.0.
Transmission

Faecal – oral

  • Small infecting dose may lead to carrier state
  • Large infecting dose will lead to overt disease
Gepgraphical distribution of cholera
Gepgraphical distribution of cholera. This file is taken from wikimedia commons and is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.
Epidemiology
May become endemic where standards of environmental sanitation and personal hygiene are low (ie deltas of ganges river)
Pathogenesis
vibrios multiple in small intestine producing endotoxinàstimulates cAMPàcauses secretory diarrheaàPatients rapidly lose water sodium, potassium and bicarbonateàleads to hypovolaemia, reduced CO and acidosis.
Clinical features
Most are asymptomatic, many have mild disease and very few have fulminant disease.
Vomiting followed by diarhoea (severe and watery white-flecked with mucous=’rice water stool’)
Fever is unusual except in children
No abdo pain initially
Hypoglycaemia in kids

[image from TopNews]

Complications
Severe Dehydration- death is usually due to hypovolaemic shock +its complications (AKI)
Diagnosis
  • Direct darkfield microscopy of perianal swab
  • Culture in TCBS agar (yellow colonies overnight)
Treatment
  • FLUID REPLACEMENT = key to treatment. (with adequate hydration all patients should recover)
  • Ciprofloxacin=effectively decreasing the duration of the clinical illness by eliminating the vibrio from the faeces.
 
Prevention
Surveillance and prompt reporting allow for containing cholera epidemics rapidly.

In many endemic countries, exists as a seasonal disease, occurring during rainy seasons.

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Dr Tom Leach

Dr Tom Leach MBChB DCH EMCert(ACEM) currently works as a GP Registrar and an Emergency Department CMO in Australia. He is also a Clinical Associate Lecturer at the Australian National University. After graduating from his medical degree at the University of Manchester in 2011, Tom completed his Foundation Training at Bolton Royal Hospital, before moving to Australia in 2013. He started almostadoctor whilst a third year medical student in 2009. Read full bio

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