Dukoral^® is an oral vaccine with a documented protective effect against diarrhea caused by cholera. The vaccine stimulates a protective immune response in the gut and has demonstrated a protective efficacy against cholera of approximately 85%. The vaccine is suitable for travelers and is indicated for use in adults and children over two years of age. Pregnant and lactating women may use it.

Cholera is an acute intestinal infection often caused by eating food or drinking water contaminated with the Vibrio cholerae bacteria. In its most severe form, the disease can cause a sudden onset of acute watery diarrhea that can lead to severe dehydration, kidney failure and ultimately death if treatment is not promptly given. Most people infected with cholera do not develop any symptoms, although the bacterium is present in their feces for 7-14 days, potentially infecting other individuals.

Morbidity and mortality

Cholera remains a global threat, particularly in developing countries where access to safe drinking water and adequate sanitation cannot be guaranteed. The number of cholera cases reported to the WHO in 2006 was close to 240 000 cases, including approximately 6300 deaths. It is likely the morbidity and mortality caused by V. cholerae is grossly underreported – less than 10% - to the WHO.  As a result, the true burden of this disease is severely underestimated.

Geographical distribution

Cholera remains a global threat. Almost every developing country, where poor sanitary conditions prevail, faces cholera outbreaks and the threat of a cholera epidemic. Altogether seven cholera pandemics have been reported. The latest, still ongoing pandemic started in Indonesia in 1961, spreading to Africa in 1971 and to the Americas in 1991. Cholera is considered endemic in many countries.

Transmission

Cholera is spread by fecal contamination of water and food, linked to poor sanitation. Person-to-person transmission of cholera is rare.

Symptoms

About 75% of people infected with cholera do not develop symptoms. Of those who do develop symptoms, 80% are considered mild to moderate cases and 10 to 20% are severely affected. Children and the elderly are most susceptible.

Symptoms include acute, profuse watery diarrhea (“rice-water stools”) and often vomiting. Tachycardia, loss of skin turgor, dry mucous membranes, hypotension and thirst are often signs of dehydration. In extreme cases and if left untreated, severe dehydration can lead to kidney failure and death. Cholera is one of the most rapidly fatal infectious illnesses known.

Treatment and prevention

Rehydration is the key form of treatment. Mild or moderate dehydration can be treated with simple oral rehydration solutions containing salts and glucose. Severe cases of dehydration require treatment with intravenous fluids and antibiotics. WHO recommends that antibiotics are only used in severe cases as overuse of antibiotics has led to the emergence of multiresistant strains, some of which where found to be highly virulent.

Cholera can be prevented through the provision of clean water and proper sanitation. For travelers to endemic areas, it is recommended to “boil it, cook it, peel it, or forget it” and to avoid eating high-risk foods. An internationally licensed oral vaccine is currently available on the market and is suitable for travelers. In 2006, WHO published official recommendations for oral vaccines use in complex emergencies.