Cholera

Cholera is endemic in several areas of the world, including parts of India and Bangladesh. From these areas, cholera has been disseminated throughout the world during several pandemics, or worldwide outbreaks. In the United States, a cholera pandemic that lasted from 1832 to 1849 killed 150,000 people; in 1866, another cholera pandemic killed 50,000 U.S. citizens. The most recent pandemic, which began in the 1960s and lasted until the early 1980s, involved Africa, Western Europe, the Philippines, and Southeast Asia. Smaller outbreaks, such as the Rwanda epidemic of 1994, are characteristic of wartime and famine conditions, in which large numbers of people concentrate in one place where sanitary conditions are poor to nonexistent.

Because of the nature of V. cholerae infection, past epidemics can lead to future epidemics. People recovering from cholera continue to shed the organism in their feces for weeks to months after the initial infection. These people are called convalescent carriers. Another kind of carrier, called a chronic carrier, continues to shed the bacteria for years after recovery. In both carrier types, no symptoms are present. With the ease of worldwide transportation, carriers can travel throughout the world, spreading V. cholerae wherever they go. If a carrier visits an area with less-than-ideal sanitary conditions or does not wash his or her hands after using the bathroom, the deadly V. cholerae bacteria can be easily transmitted.