Cholera

What is cholera?

Cholera is an acute, infectious disease caused by the consumption of water or food contaminated with the bacterium Vibrio cholerae.

Cholera is a public health concern in developing countries all over the world, especially in Africa, south Asia, and Latin America. Cases among travelers to and from developed countries are rare; however, some outbreaks in the United States have been caused by contaminated seafood brought into the country by travelers.

What causes cholera?

Vibrio cholerae is usually found in impure water supplies because of the unsanitary disposal of excrement. Person-to-person transmission is rare. It is usually transmitted by consuming contaminated food or water from:

Municipal water supplies
Ice made from municipal water
Foods and beverages bought from street vendors
Vegetables irrigated with fresh sewage
Raw or inadequately cooked fish and seafood taken from sewage-polluted waters

How does the Vibrio cholerae bacterium affect the body?

The bacterium that causes cholera is usually very sensitive to the acids present in the stomach and digestive tract. Small amounts of bacteria are killed by the stomach acids before they can establish themselves in the body. Approximately 75 percent of people infected will not develop any symptoms; however, the bacteria is still present in their feces for seven to 14 days, during which time they can infect other people, paticularly if they have poor personal hygiene habits. Eighty percent of people who do develop symptoms will develop a mild to moderate gastroenteritis. The remaining 20 percent of those infected will develop severe cholera with profuse watery diarrhea referred to as "rice-water stools," and sometimes vomiting, both of which lead to severe dehydration. Signs and symptoms may include tachycardia, dry mucous membranes, hypotension, and muscle cramps. If untreated, the severe dehydration can ultimately lead to shock and death. People with weakened immune systems are at greater risk for dying from cholera infection.

Can cholera be prevented?

The best preventives for cholera are:

Frequent handwashing
Only use water that has been boiled or chemically disinfected for:
- Drinking, or preparing beverages such as tea or coffee
- Brushing teeth
- Washing face and hands
- Washing fruits and vegetables
- Washing eating utensils and food preparation equipment
- Washing the surfaces of tins, cans, and bottles that contain food or beverages
Do not eat food or drink beverages from unknown sources
- Any raw food could be contaminated, including:
  - Fruits, vegetables, salad greens
  - Unpasteurized milk and milk products
  - Raw meat
  - Shellfish
  - Any fish caught in tropical reefs rather than the open ocean

Two oral cholera vaccines are available that been proven safe and effective, but neither is available in the United States. According to the World Health Organization, six months after the vaccine is administered, the efficacy rate can be up to 85 to 90 percent in all age groups. Currently, no country requires the cholera vaccine for entry if arriving from cholera-infected countries.

Treatment for cholera

For diarrhea that is worse than normal, it is best for the traveler to consult a doctor rather than try self-medication. Seek medical help if diarrhea becomes severe and watery, or if vomiting occurs.

Specific treatment for cholera will be determined by your doctor based on: