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

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

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