Cause of Typhoid Fever

An infection with the Salmonella typhi bacteria -- also known as typhoid fever bacteria -- is what causes typhoid fever. When ill people shed Salmonella typhi in their stool, it may get into the food or water supply, causing the disease to spread. In many cases, contaminated food and water are the main culprits.

What is Typhoid?

What Is the Cause of Typhoid Fever?

Typhoid fever is caused by an infection with the bacteria Salmonella typhi.

How Does Salmonella Typhi Cause Typhoid Fever?

Salmonella typhi bacteria live only in humans. People with typhoid fever carry the bacteria in their bloodstream and intestinal tract. About 3 to 5 percent of people still carry the bacteria, even if symptoms go away with proper treatment. These people are known as typhoid fever carriers. The most famous was Mary Mallon, better known as Typhoid Mary.

How Is the Disease Transmitted?

You can get typhoid fever if you eat food or drink beverages that have been handled by a person who is shedding the bacteria, or if sewage contaminated with the bacteria gets into the water you use for drinking or washing food. Therefore, typhoid fever is more common in areas of the world where handwashing is less frequent and water is more likely to be contaminated with sewage.

Over the past 10 years, travelers from the United States to Asia, Africa, and Latin America have been especially at risk.