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cholera

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cholera

introduction

  • an acute intestinal infection caused by ingestion of food or water contaminated with the bacterium Vibrio cholerae
  • 3–5 million cholera cases and 100 000–120 000 deaths worldwide due to cholera every year
  • 75% are asymptomatic and shed the bacteria via faeces for 10-14 days
  • incubation period is from less than one day to five days
  • most symptomatic cases have mild to moderate symptoms
  • in 20% of those who develop symptoms, particularly the malnourished or HIV / AIDS infected, an enterotoxin causes a copious, painless, watery diarrhoea that can quickly lead to severe dehydration and death within hours if treatment is not promptly given
    • most patients also develop vomiting
  • 80% of cases can be successfully treated with oral rehydration salts

vaccination

  • oral killed vaccinations are available which lasts for up to 6 months and also reduces enterotoxigenic E.coli traveller's diarrhoea risk by 15% for ~ 3 months
  • it is only recommended to those at high risk
  • use of the parenteral cholera vaccine has never been recommended by WHO due to its low protective efficacy and the high occurrence of severe adverse reactions

pandemics

  • during the 19th century, cholera spread across the world from its original reservoir in the Ganges delta in India.
  • six subsequent pandemics killed millions of people across all continents
  • the current (seventh) pandemic started in South Asia in 1961, and reached Africa in 1971 and the Americas in 1991.
  • cholera is now endemic in many countries
  • Two serogroups of V. cholerae – O1 and O139 – cause outbreaks
    • V. cholerae O1 causes the majority of outbreaks, while O139 – first identified in Bangladesh in 1992 – is confined to South-East Asia
cholera.txt · Last modified: 2013/12/31 03:49 by gary1