Cholera

Background/Epidemiology

  • Caused by Vibrio cholerae
  • Pandemics have occurred throughout history, most recently in South/Central America (having spread from the Middle East and Africa)
    • Frequent outbreaks/epidemics in Africa
    • Spread via stools/vomit of infected patients (symptomatic or not) or via consumption of infected water, shellfish or food.  Organisms often thrive in water (can survive up to 8 weeks- common epidemics during flooding)
      • Despite this, risk for travellers is relatively low (2-3/1000000)
      • A high infecting dose is required.
  • Incidence is increasing

Subtypes

  • Vibrio cholerae can be divided as
    • O1 type
      • Classical
      • El Tor (often more resistant and more prolonged/severe disease)
        • Each of these (Classical and El Tor) can be subdivided further into Inaba, Ogawa and Hikojima types
    • O139
  • Incubation period 2-5 days

Clinical Presentation

  • Severe cases can cause acute/sudden onset diarrhoea followed by watery (rice-water) diarrhoea and vomiting
    • Causes rapid and severe dehydration
      • Muscle cramps may be present
      • Shock and oliguria
      • Eventually, circulatory failure and death if untreated.
  • However, many cases will not be severe and only cause mild diarrhoea and illness.
  • If rapid treatment is initiated for severe cases, most recover quickly.

Investigations

  • In endemic areas, this is often a clinical diagnosis
  • In non-endemic areas, stool microscopy and culture
  • Blood tests e.g. FBC, U&Es can be used to further assess severity

Management

  • Maintaining fluid balance is the most important thing
    • Ringer-lactate solution is preferred
    • Once vomiting stops (with IV rehydration), oral rehydration should start (up to 500ml/hour)
      • Total replacement/requirement may exceed 50l/day
  • Antibiotics
    • Base treatment on advice from Microbiology/Infectious diseases

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