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Cholera

an infectious disease caused by the Vibrio cholerae bacteria

Vibrio cholerae

During the 19th century, cholera spread across the world from its original reservoir in the Ganges delta in India. Seven subsequent pandemics (the latest in the 1960's and 1970's) killed millions of people across all continents. Cholera is still common in many parts of the world (especially Africa and Asia), with an estimated 3-5 million cases and over 100,000 deaths occurring each year.

Cholera is most likely to be found and spread in places with inadequate water treatment, poor sanitation, and poor hygiene practices. The cholera bacterium lives in the environment in brackish rivers and coastal waters. The vast majority of cases can be traced to water sources contaminated by human waste. Food transmission can occur when people harvest seafood (especially shellfish) from infected waters, as Vibrio cholerae accumulates in the plankton upon which the shellfish feed. Flies can also help spread the bacteria. While transmission via casual contact with an infected individual is possible, it is extremely rare.

Once ingested, Vibrio cholerae settles in the intestines, where it produces an intense inflammation that soon results in a general body poisoning. The poison causes diarrhea and vomitting, which can cause severe dehydration. The dehydration, combined with other chemical changes within the body, can cause death within five days of symptoms first appearing.

Signs and symptoms of cholera dehydration include irritability, lethargy, sunken eyes, a dry mouth, extreme thirst, dry and shriveled skin that's slow to bounce back when pinched into a fold, little or no urine output, low blood pressure, and an irregular heartbeat (arrhythmia). Children with cholera have the same signs and symptoms adults do, but they are particularly susceptible to low blood sugar (hypoglycemia) due to fluid loss. Only about 1 in 10 infected people develop symptoms, usually within days of infection. The only way to confirm a diagnosis of cholera is to identify the bacteria in a stool sample.

Immediate treatment of cholera consists of fluid replacement, either orally or intravenously. Antiobiotic treatments for one to three days can shorten the course of the disease and reduce the severity of the symptoms, but most patients can recover without antiobiotics as long as the dehydration is aggressively treated.

Cholera vaccines are available, but the World Health Organization focuses most of its efforts on prevention through strict sanitary measures and fly control.

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The Robinson Library >> Medicine >> Infectious and Parasitic Diseases

This page was last updated on 10/24/2017.