Cholera

What to know about it:

The Facts on Cholera

• Causes of Cholera
• Symptoms and Complications of Cholera
• Diagnosing Cholera
• Treating and Preventing Cholera

The Facts on Cholera

Cholera is a bacterial infection of the small bowel that can cause severe diarrhea and dehydration.
There have been seven great pandemics (worldwide epidemics) of cholera in history. The seventh began in 1961, when cholera re-emerged in Indonesia and swept across most of the world, and it still lingers today. At the beginning of the 21st century, cholera infected around 300,000 people per year worldwide; of these, about 10,000 died.
Cholera settles wherever poor hygiene permits it to infect humans, who appear to be cholera's only hosts. The bacterium that causes cholera is most productive in times of flood and war, since these events can reduce the availability of clean water. Cholera continues to occur in Asia, Africa, the Middle East, and South and Central America.
Worldwide, cholera kills about 4% of the people who develop severe symptoms. That includes people who are treated too late or inappropriately and those who never reach a doctor. Fewer than 1% of people with severe cholera die if they're quickly and properly treated.

Causes of Cholera

Cholera is caused by a bacterium called Vibrio cholerae, a very close cousin of the bacterium that causes gastroenteritis. Once swallowed, it settles in the lining of the small bowel or intestine. Many bacteria die, and others are swept out, but the colony usually hangs around for a week or two. During that time, it releases a toxin (poison) that can cause the body to flush liquid into the small bowel, creating watery diarrhea.
The bacterium that causes cholera is usually transmitted by water contaminated with human feces, but it can also be transmitted by ingesting contaminated food, especially raw or undercooked seafood and shellfish. Most people infected with cholera have no symptoms, yet they carry the bacteria for a few weeks, excreting them slowly into the water supply.
Naturally, this isn't a major problem in countries with flush toilets and sewage plants. Canada, the US, and Western Europe rarely report cholera, and if they do, it's almost always seen in someone who has returned from a high-risk country.

Symptoms and Complications of Cholera

Approximately 25% of people who ingest the bacteria actually develop the particular symptoms that we call cholera. Of those, 80% will experience symptoms that are only of mild or moderate severity, while up to 20% will develop severe watery diarrhea that can be life-threatening if not treated properly.
It is not known why some people develop cholera while others are unaffected by the bacterial toxin. Most adults in cholera-endemic areas have some antibodies, which helps to protect them from developing the disease. In these countries, severe symptoms are far more common in children.
Vibrio bacteria are killed by stomach acid. Research has shown that people with low acidity in their stomach (e.g., people taking antacid medications) are much more prone to cholera. Also, people with type O blood seem to be more at risk.
If symptoms of cholera occur, the main symptom is watery diarrhea, which can be severe enough to rapidly drain the body of vital water, salts, and minerals. The first watery stool appears 1 to 3 days after infection, and from then on the body can lose up to one liter of liquid an hour. Vomiting may appear at the same time.
Other symptoms of severe cholera are:

• muscle cramps
• reduced or no urination
• weakness
• low pulse
• sunken-looking eyes
• wrinkled skin on fingers

Cholera usually runs its course in 3 to 6 days, but if it is not treated it can cause shock from dehydration, kidney failure, coma, and death.