Cholera

Cholera is an intestinal infection caused by a bacterium known as Vibrio cholerae. Cholera is acquired through ingestion of contaminated food or water. It is rarely spread from person-to-person. The incubation period ranges from less than one to five days. In most cases, infection with Vibrio cholerae causes either no symptoms or mild diarrhea. Some, however, develop profuse watery diarrhea, usually with vomiting, leading to profound dehydration, which may be fatal. The cornerstone of treatment is rehydration, usually with oral rehydration solution. Severe cases may require intravenous fluids. Antibiotics are also given, usually tetracycline or doxycycline, though quinolone antibiotics such as ciprofloxacin and levofloxacin are also effective. A recent study in Bangladesh showed that a single 1-gram dose of azithromycin (Zithromax) was significantly more effective than a single 1-gram dose of ciprofloxacin (see the New England Journal of Medicine).

Cholera is rare in travelers, including those visiting countries where cholera outbreaks are occurring. In previous years, cholera vaccination was required for entry into many countries, but is no longer required of any traveler. As of August 2000, the only cholera vaccine approved for use in the United States was no longer being manufactured or sold. (See the Centers for Disease Control for details.) The vaccine had not been generally recommended because it reduces the rate of infections by no more than 50%, is effective for no more than 3-6 months, and frequently causes pain at the injection site. Three oral vaccines have been developed, including Orochol (Mutacol) and Dukoral. Mutacol and Dukoral are licensed in Canada and Australia and Dukoral is licensed in the European Union, but none of the oral cholera vaccines have been approved in the United States. The vaccines are generally safe, but protection has not been shown to last for more than six months. According to Health Canada and the National Travel Health Network and Centre (U.K.), oral cholera vaccines are not recommended for most travelers, but may be considered for those at higher than average risk, such as health professionals in endemic areas, aid workers in refugee camps, and those traveling to remote areas where cholera epidemics are occurring and there is limited access to medical care. See the review in the Weekly Epidemiological Record (PDF) for detailed information regarding the new vaccines.

Cholera is best prevented by careful selection of food and beverages, as described elsewhere. Breast-feeding appears to be protective against cholera.

From the World Health Organization (WHO)

Cholera

Cholera: Basic Facts for Travelers

Cholera Fact Sheet

From the Centers for Disease Control (CDC)

Cholera

From the Pan American Health Organization

Cholera in the Americas

From Health Canada

Oral Cholera Vaccination

From the Reviews in Medical Microbiology

S. Kabir. Cholera vaccines: the current status and problems. Reviews in Medical Microbiology 2005, 16: 101-116.