Typhoid Fever is an acute illness associated with fever caused by the Salmonellae Typhi bacteria. The bacteria is deposited in water or food by a human carrier, and is then spread to other people in the area. The incidence of the illness in the United States has markedly decreased since the early 1900's. This improvement is the result of improved environmental sanitation. Mexico and South America are the most common areas for U.S. citizens to contract typhoid fever. India, Pakistan and Egypt are also known high risk areas for developing this disease.
Typhoid Fever is contracted by the ingestion of the bacteria in contaminated food or water. Patients with acute illness can contaminate the surrounding water supply through the stool, which contains a high concentration of the bacteria. Contamination of the water supply can, in turn, taint the food supply. Also, about 3-5% of patients become carriers of the bacteria after the acute illness. Some patients suffer a very mild illness that goes unrecognized. These patients can become long- term carriers of the bacteria. The bacteria multiplies in the gallbladder, bile ducts, or liver and passes into the bowel. The bacteria can survive for weeks in water or dried sewage. These chronic carriers may have no symptoms and can be the source of new outbreaks of typhoid fever for many years.
After the ingestion of contaminated food or water, the Salmonella bacteria invades the small intestine and enters the blood stream temporarily. It is carried by white blood cells in the liver, spleen, and bone marrow. The bacteria then multiplies in the cells of these organs and reenters the blood stream. Patients develop symptoms, including fever, when the organism reenters the blood stream. Bacteria invade the gallbladder, biliary system, and the lymphatic tissue of the bowel. Here, they multiply in high numbers. The bacteria passes into the intestinal tract and can be identified for diagnosis in cultures from the stool tested in the laboratory.
The incubation period is usually 1-2 weeks and the duration of the illness is about 4-6 weeks. The patient experiences:
- poor appetite,
- generalized aches and pains,
- fever, and
Persons with typhoid fever usually have a sustained fever as high as 103 to 104 degrees Fahrenheit (39 to 40 degrees Centigrade).
Chest congestion develops in many patients and abdominal pain and discomfort are common. The fever becomes constant. Improvement occurs in the third and fourth week in those without complications. About 10% of patients have recurrent symptoms (relapse) after feeling better for one to two weeks. Relapses are actually more common in individuals treated with antibiotics.
Typhoid Fever is treated with antibiotics which kill the Salmonella bacteria. Prior to the use of antibiotics, the fatality rate was 10%. Death occurred from overwhelming infection, pneumonia, intestinal bleeding, or intestinal perforation. With antibiotics and supportive care, mortality has been reduced to 1-2%.
Several antibiotics are effective for the treatment of typhoid fever. Chloramphenicol was the original drug of choice for many years. Because of rare serious side effects, chloramphenicol has been replaced by other effective antibiotics. If relapses occur, patients are retreated with antibiotics.
The carrier state, which occurs in 3-5% of those infected, can be treated with prolonged antibiotics. Often, removal of the gallbladder, the site of chronic infection, will cure the carrier state.
For those traveling to high risk areas, vaccines are now available.