S. typhi are spread by contaminated food, drink, or water. Following ingestion, the bacteria spread from the intestine to the intestinal lymph nodes, liver, and spleen via the blood where they multiply.

Salmonella may directly infect the gallbladder through the hepatic duct or spread to other areas of the body through the bloodstream.

Early symptoms are generalized and include fever, malaise and abdominal pain. As the disease progresses, the fever becomes higher (greater than 103 degrees Fahrenheit), and diarrhea becomes prominent. Weakness, profound fatigue, delirium, and an acutely ill appearance develop.

A rash, characteristic only of typhoid and called "rose spots," appears in some cases of typhoid. Rose spots are small (1/4 inch) red spots that appear most often on the abdomen and chest. Typically, children have milder disease and fewer complications than adults.

A few people can become carriers of S. typhi and continue to shed the bacteria in their feces for years, spreading the disease, as in the case of "Typhoid Mary" in New York over one hundred years ago.

Although typhoid fever is common in developing countries, less than 400 cases are reported in the U.S. each year, most brought in from abroad.

• Severe headache
• Fever
• Loss of appetite
• General discomfort, uneasiness, or ill feeling (malaise)
• Rash (rose spots) appearing on the lower chest and abdomen during the second week of the fever
• Abdominal tenderness
• Constipation, then diarrhea
• Stools, bloody
• Slow, sluggish, lethargic
• Fatigue
• Weakness
• Nosebleed
• Chills
• Delirium
• Confusion
• Agitation
• Fluctuating mood
• Difficulty paying attention (attention deficit)
• Hallucinations

• An elevated white blood cell count in blood
• A blood culture during first week of the fever can show S. typhi bacteria
• A stool culture
• An ELISA test on urine may show Vi antigen specific for the bacteria
• A platelet count (decreased platelets)
• A fluorescent antibody study (demonstrates Vi antigen, which is specific for typhoid)

The illness usually resolves in 2 to 4 weeks with treatment. The outcome is likely to be good with early treatment, but becomes poor if complications develop. Cases in children are milder, and are more debilitating in the elderly.

Relapse may occur if the treatment has not fully eradicated the infection.

• Intestinal hemorrhage (severe GI bleeding)
• Intestinal perforation
• Kidney failure
• Peritonitis

Vaccines are recommended for travel outside of the U.S., Canada, northern Europe, Australia, and New Zealand, and during epidemic outbreaks.

Immunization is not always completely effective and at-risk travelers should drink only boiled or bottled water and eat well cooked food. Experimentation with an oral live attenuated typhoid vaccine is now underway and appears promising.

Adequate water treatment, waste disposal, and protection of food supply from contamination are important public health measures. Carriers of typhoid must not be allowed to work as food handlers.