What is typhoid fever?

Causes and Symptoms

Typhoid fever, a serious disease with the potential to become epidemic under conditions of poor sanitation, is caused by the bacterium Salmonella enterica, serotype Typhi (formerly Salmonella typhi). These bacteria are transmitted to humans through the consumption of water or food contaminated with the feces from individuals who carry the serotype Typhi but who most often remain asymptomatic.

An infective dose of bacteria in susceptible individuals is estimated to be quite small, generally less than one thousand cells. The ingested bacteria pass through the stomach to the small intestines, where they establish an initial site of infection. These intestinal lesions usually ulcerate, and the bacteria spread to other body tissues via the bloodstream and lymphatic system. The organs most often affected by these secondary infections include the liver, spleen, kidneys, bone marrow, and especially the gallbladder. Symptoms include headache, abdominal pain, general malaise, and a generalized rash with rose-colored spots. If no complications ensue, then the fever will abate after about three weeks, but mortality rates average about 15 percent in untreated cases.

Treatment and Therapy

The first drug with demonstrable effectiveness in treating typhoid fever was chloramphenicol, which became generally available in 1948. Other antibiotics, notably ampicillin and ciprofloxacin, have largely replaced chloramphenicol as the treatment of choice, and their use has reduced the death rate to approximately 1 percent. Improved sanitation and living conditions since the 1920s have drastically reduced the incidence of this disease in the United States, although worldwide it remains a major public health concern. The World Health Organization estimates that at least 16 million cases and more than 200,000 deaths can be attributed to typhoid fever each year.

Vaccines are available to prevent typhoid fever, but their effectiveness is suboptimal. Temporary immunity is acquired by about 60 to 75 percent of vaccinated individuals. Individuals who recover from the disease often become healthy carriers of the bacteria, and surgical removal of the gallbladder may be necessary to rid them of their carrier status.

Perspective and Prospects

The most famous case of a healthy carrier of the typhoid fever bacteria was a cook by the name of Mary Mallon, called “Typhoid Mary,” who worked in several establishments in New York during the period from 1902 to 1915. In those years, she was linked to several different outbreaks of typhoid fever, resulting in fifty-one cases of illness and three deaths. When she repeatedly refused to cooperate with public health authorities, she was eventually taken into custody and confined in a state hospital. After almost three years, she was released, but she soon skipped parole and disappeared. Four years later, she was apprehended again as the source of a typhoid fever outbreak that involved twenty-five cases and two deaths. She was returned to the secure hospital in 1915, where she remained until her death in 1938. The important legal issues generated by her case, including incarceration for having an infectious disease and forced surgery, were the driving forces behind the founding of the American Civil Liberties Union (ACLU).

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Vorvick, Linda J., Jatin M. Vyas, and David Zieve. "Typhoid Fever." MedlinePlus, June 9, 2011.