How does a person get cholera?A person may get cholera by drinking water or eating food contaminated （污染）with the cholera bacterium（细菌）. The disease can spread rapidly in areas with inadequate treatment of sewage（污水） and drinking water. The cholera bacterium may also live in the environment in polluted rivers and coastal waters. Shellfish eaten raw(生肉) have been a source of cholera, and a few persons in the United States have contracted cholera after eating raw or undercooked shellfish from the Gulf of Mexico. The disease is not likely to spread directly from one person to another; therefore, casual contact with an infected person is not a risk for becoming ill.In January 1991, cholera appeared in South America and quickly spread to several countries. A few cases have occurred in the United States among persons who traveled to South America or ate contaminated food brought back by travelers.Cholera has been very rare in industrialized nations for the last 100 years; however, the disease is still common today in other parts of the world, including the Indian and sub-Saharan Africa. Although cholera can be life-threatening, it is easily prevented and treated. In the United States, because of advanced water and sanitation systems（卫生系统）, cholera is not a major threat; however, everyone, especially travelers, should be aware of how the disease is transmitted and what can be done to prevent it.
