Cholera
Background information
- What Is Cholera?
Cholera is an acute bacterial intestinal infection with a short incubation period, typically one to five days. Cholera causes watery diarrhea and vomiting that can lead to severe dehydration and death in less than 24 hours if not treated promptly. In areas where cholera is endemic, the disease mainly affects children.
- Global Burden
In 2004, the WHO reported that 101,383 cases of cholera occurred in 56 countries resulting in 2,345 deaths. Case-fatality rates in epidemic conditions can exceed 40 percent, making cholera prevention a major public health objective.
- Geographic Distribution
The majority of cases currently occur in sub-Saharan Africa and Southeast Asia, but distribution varies. During 2004, major outbreaks occurred in Cameroon, Chad, Guinea, Mali, Niger, Senegal, and Zambia.
- Causative Agent/Transmission
Cholera is caused by ingestion of food or water contaminated with the bacterium Vibrio cholerae. Most sudden, large outbreaks are linked to a contaminated water supply. Rarely, cholera can be transmitted by direct person-to-person contact. Until 1992, the only known cholera agent was Vibrio cholerae O1, but in that year a new serogroup, O139, was observed and found to be the cause of several epidemics in Asia.
Presentation
V. cholerae produces an enterotoxin that induces the intestine to release fluid, causing abundant, watery diarrhea that can quickly lead to severe dehydration. Frequent vomiting can exacerbate dehydration. If
the dehydration is not addressed, cholera can be fatal. Most healthy people have the ability to fight a cholera infection without manifesting symptoms; however, about 10 percent of those infected develop severe disease.
Trends
Cholera remains a global threat and one of the key indicators of low development level. It is a particularly dangerous problem in places with limited access to clean water. Most developing countries are at risk for
cholera outbreaks. Current vaccines do not protect against O139. The Institut Pasteur cautioned in 2003 that this new strain “may well become the origin of an eighth cholera pandemic.”
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