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