- Cholera is an acute intestinal bacterial infection acquired through ingestion of contaminated water, food, shellfish, or bodily fluids from infected patients.
- Risk is very low in typical travelers, even in countries with cholera. Risk is highest for health care workers (HCWs) and aid and refugee workers handling patients with cholera.
- Symptoms in travelers are generally mild and resemble typical travelers' diarrhea with acute, watery diarrhea.
- Consequences of infection rarely occur in travelers but may include severe dehydration, requiring oral or intravenous rehydration.
- Prevention (essentially 100% effective) includes food and beverage precautions and frequent, thorough handwashing.
- Cholera vaccination (only indicated for certain at-risk groups), depending on the brand, is taken orally either as a single dose 10 days before possible exposure or in a 2- or 3-dose–series given 1 week apart.
- Vaccine side effects are most commonly mild gastrointestinal symptoms (e.g., nausea and vomiting), fatigue, or lack of appetite.
- Duration of vaccine protection is 3 to 6 months for the U.S. vaccine, with a booster recommended every 6 months while at risk.
Cholera is an acute bacterial intestinal infection that is rare in typical travelers. Symptoms in healthy travelers resemble those of travelers' diarrhea (TD). TD differs from cholera, which is a severe, dehydrating illness that could rapidly lead to death in local people (who may be malnourished with weak immune systems). Cholera is especially responsive to proper oral or intravenous rehydration, with or without a single dose of an appropriate antibiotic.
Cholera occurs mainly in developing countries with inadequate sanitation and lack of clean drinking water and in areas where infrastructure may have broken down due to war or natural disasters. Cholera is endemic in Africa and Asia where focal outbreaks periodically occur. Recent outbreaks have occurred in the Horn of Africa, Democratic Republic of Congo, Yemen, Haiti (introduced after the earthquake in 2010), Dominican Republic, and Cuba.
Cholera is rarely reported in travelers. In the U.S. (where a cholera vaccine was not available from 1999 through late 2016), 42 cases (mostly imported from Haiti) were reported in 2011, and fewer than 25 cases per year have been reported since 2012.
Cholera is most commonly acquired from drinking contaminated water or through the consumption of fecally contaminated food (all types of food can be contaminated by infected food handlers). The free-living bacterial organisms that cause cholera are also found in fresh and brackish waters, where they attach to the shells of crustaceans such as shrimp, crabs, and lobsters and to the skin of fish, which are potent sources of infection if inadequately cooked.
Current risk in travelers is very low, but the following circumstances increase the likelihood of infection:
- Ingestion: Eating or drinking fecally contaminated food or water.
- Occupational: HCWS and aid and refugee workers handling patients with cholera.
- Seasonal: In endemic areas of India and Bangladesh, cholera is more common during the hot season (before the rainy season begins) and at the start and end of the rainy season in areas where cholera has been recently introduced.
Risk of acquiring cholera or having severe disease is increased in persons with blood type O, low gastric acidity (from antacids or partial stomach removal), chronic medical conditions such as heart or kidney disease, or HIV coinfection; travelers visiting friends and relatives in the family's country of origin or without access to medical care; nonbreastfed infants and young toddlers; and pregnant women (increased risk of fetal loss due to severe dehydration).
Travelers on typical tourist itineraries with standard accommodations, who observe appropriate food, water, and hand-hygiene precautions, are at almost no risk of clinical cholera, even in highly endemic countries.
Symptoms most commonly resemble those of TD in otherwise healthy travelers; severe cholera is uncommon. In most cases, cholera lasts from 1 day to several days and presents as acute, profuse, watery diarrhea without blood or mucus; nausea and vomiting can also occur.
In endemic areas, symptoms develop within a few hours up to 5 days following exposure and most commonly include watery diarrhea without a fever. Infection is often mild.
Consequences of Infection
Severe cholera is characterized by acute, profuse watery diarrhea (rice-water stools), nausea, and vomiting. Signs and symptoms include rapid heartbeat, dry skin and mucous membranes, low blood pressure, thirst, and muscle cramps. Rapid loss of bodily fluids leads to severe dehydration, shock, and death within hours, although with proper rehydration, the death rate is less than 1%.
Need for Medical Assistance
If diarrhea is suggestive of cholera, the most important measure is to maintain hydration by drinking fluids. If the diarrhea causes dehydration, any commercially available oral rehydration solution containing glucose, sodium chloride, potassium chloride, and sodium bicarbonate (to be dissolved in safe drinking water) should be taken. Hospitalization for administration of intravenous fluids may sometimes be needed in more severe cases in travelers. A single dose of an appropriate antibiotic may reduce fluid requirements and the duration and severity of illness. Zinc supplementation reduces the severity and duration of cholera and other diarrheal diseases in children in resource-limited areas.
Observance of food, water, and hand-hygiene precautions are essentially 100% effective (regardless of immunization status) in typical travel situations. See Food and Beverage Precautions. HCWs and aid and refugee workers handling patients with cholera should also shower and change clothes at the end of their shifts.
An oral cholera vaccine (which contains live, weakened bacteria) for persons aged 18-64 years is available in the U.S. Several cholera vaccines for persons 1 year and older are available outside the U.S.
Vaccination, which is not 100% effective, is generally not recommended for typical travelers (for whom risk is very low, even in countries where cholera epidemics occur), provided that appropriate food, water, and hand-hygiene precautions are observed. Vaccination is recommended for HCWs, aid and refugee workers, and certain vulnerable populations (see Risk Factors) traveling to areas with very acute and as-yet-uncontrolled epidemics.
Duration of protection against cholera is 3 to 6 months for the U.S. vaccine and 6 months to 2 years for non-U.S. vaccines.
Vaccine side effects are usually mild and include fatigue, headache, abdominal pain, nausea, vomiting, lack of appetite, and (rarely) diarrhea for the U.S. vaccine and mild gastrointestinal symptoms and fever for non-U.S. vaccines.
Persons with underlying medical conditions or who have concerns about the vaccine should speak to their health care provider before vaccine administration.
Avoid all food and drink from 1 hour before until 1 hour after receiving a dose of cholera vaccine.
The U.S. vaccine is given as follows:
- Persons aged 18-64 years: 1 oral dose at least 10 days prior to possible exposure.
- A booster dose is given every 6 months if at continued risk.
The non-U.S. vaccine is given as follows:
- Persons aged 2-5 years: 3 oral doses given at least 1 week apart.
- Persons 6 years and older: 2 oral doses given at least 1 week apart.
- All doses should be completed at least 1 week before possible exposure.
- A booster dose is given 6 months later for continued cholera protection.
- If more than 5 years have elapsed since the last dose, a complete primary series is needed.