Typhoid fever is an acute illness associated with fever caused by the Salmonella enterica serotype Typhi bacteria. It can also be caused by Salmonella paratyphi, a related bacterium that usually causes a less severe illness. The bacteria are deposited in water or food by a human carrier and are then spread to other people in the area.
The incidence of typhoid fever in the United States has markedly decreased since the early 1900s, when tens of thousands of cases were reported in the U.S. Today, less than 400 cases are reported annually in the United States, mostly in people who have recently traveled to Mexico and South America. This improvement is the result of better environmental sanitation. India, Pakistan, and Egypt are also known as high-risk areas for developing this disease. Worldwide, typhoid fever affects more than 21 million people annually, with about 200,000 people dying from the disease.
Typhoid fever is contracted by drinking or eating the bacteria in contaminated food or water. People with acute illness can contaminate the surrounding water supply through stool, which contains a high concentration of the bacteria. Contamination of the water supply can, in turn, taint the food supply. The bacteria can survive for weeks in water or dried sewage.