Wellcome Library, London
Depiction of the changes brought by cholera
Symptoms and Causative Agent
Cholera is a diarrheal illness caused by an infection of the intestine by the Vibrio cholerae bacterium.
In about 80% of cholera infections, the person will have no symptoms or very mild symptoms. However, about 20% of people with symptoms will will experience profuse watery diarrhea, vomiting, and leg cramps.
Symptoms can occur within two hours to five days after initial exposure to V. cholera.
Cholera is transmitted by ingesting food or water contaminated with V. cholerae. The contamination occurs when fecal matter from a sick person comes into contact with food or water supplies.
In areas with poor environmental management and overcrowding, the risk of cholera increases dramatically. Ensuring that food and water supplies are clean and well managed is the easiest way to prevent the spread of cholera. The development and use of piped water systems, chlorination facilities, water filtration, safe water storage containers, and proper sewage disposal have helped reduce the spread of cholera.
Cholera is typically not spread directly from one person to another.
Treatment and Care
People who are ill with cholera can be treated with oral rehydration fluids. Intravenous fluids may be administered if the patient is severely dehydrated.
Antibiotics may be used to reduce the severity of symptoms. However, widespread use of antibiotics in areas with many cases of cholera is generally not recommended. Antibiotics do not prevent spread of the disease, and they may lead to V. cholerae’s increasing antimicrobial resistance.
In extreme cases of cholera, diarrhea can be so profuse that severe dehydration sets in, which can lead to sunken eyes, cold skin, decreased skin elasticity, wrinkling of the hands and feet, and a bluish tint to the skin.
Death can occur within hours of symptom onset if the patient does not receive treatment.
Available Vaccines and Vaccination Campaigns
Globally, two oral cholera vaccines are available. The vaccines provide about 65%-85% protection from clinically significant cholera for a period of time from 4 months after vaccination to up to 5 years after vaccination, depending on the vaccine. Because vaccine effectiveness is somewhat low and short-term, cholera vaccines are used mainly for outbreak control and emergency use, rather than for routine vaccination.
U.S. Vaccination Recommendations
Cholera vaccines are not currently available in the United States. Water-related spread of cholera bacterium has been eliminated in the United States due to modern water and sewage treatment systems.
American citizens traveling to an area with epidemic cholera (that is, parts of Africa, Asia, or Latin America) are advised to practice simple safeguards, such as drinking only bottled water and washing hands frequently
Centers for Disease Control and Prevention. Cholera. http://www.cdc.gov/cholera/general/ Accessed 2/15/2016.
Centers for Disease Control and Prevention. Cholera vaccines. http://www.cdc.gov/cholera/vaccines.html Accessed 2/15/2016.
Centers for Disease Control and Prevention. Infectious diseases related to travel: cholera. http://wwwnc.cdc.gov/travel/yellowbook/2016/infectious-diseases-related-to-travel/cholera Accessed 2/15/2016.
World Health Organization. Cholera fact sheet. http://www.who.int/mediacentre/factsheets/fs107/en/ Accessed 2/15/2016.
Last update 25 Feb 2016
Timeline Entry: 8/31/1854
Cholera: The Pump Handle
John Snow once again made an important contribution to the understanding of cholera. During an 1854 London cholera epidemic that began in late August, Snow carefully investigated illnesses that occurred near a water pump at Cambridge and Broad streets in the Soho neighborhood. Snow proposed that the water, drawn from a downstream location on the Thames River, was contaminated with the causative agent of cholera. In fact, about 500 cholera deaths had occurred in the neighborhood near the pump in 10 days. In contrast, he showed that a nearby pump, supplied by a different company from water further upstream, did not appear to be associated with cholera.See this item in the timeline
Timeline Entry: 1906
Cholera: El Tor Strain Emerges
Felix Gotschlich (1874-1914) isolated what came to be known as the El Tor strain of cholera bacteria from Indonesian pilgrims in Egypt.
“Gotschlich isolated organisms resembling V. cholera from 6 dead Mecca pilgrims at the El Tor quarantine station on the west coast of the Sinai Peninsula. The Pilgrims did not have clinical cholera nor post mortem evidence of cholera. The organisms appeared morphologically, biochemically, and serologically like V. cholera. – Rudolf Hugh
Though the El Tor strain was not thought at the time to cause clinical disease, further studies and the emergence of the seventh cholera pandemic in 1961 showed that this strain was in fact disease-causing. About 75% of infections are asymptomatic, 18% cause mild diarrhea, and 1-2% cause severe cholera symptoms.See this item in the timeline
Timeline Entry: 2016
Cholera Vaccines Today
Today, two oral cholera vaccines are available. A whole-cell killed vaccine Dukoral, or WC-Rbs, first licensed in 1992 and manufactured by French vaccine company Valneva, is internationally licensed but not available in the United States.
Shanchol is a killed oral vaccine, similar to Dukoral, that is licensed and manufactured in India by Shantha Biotechnics. A version of it is available locally in Viet Nam.
All of the current vaccines protect against both the classic and the El Tor subtypes of cholera. Other cholera vaccines are currently in the development pipeline.See this item in the timeline