Typhoid fever is an illness caused by the bacterium Salmonella typhi. Very common worldwide, it is transmitted by food or water contaminated with feces from an infected person.

Symptoms

After infection, symptoms include:

a high fever from 103° to 104°F (39° to 40°C) that rises slowly
chills
slow pulse rate (bradycardia)
weakness
diarrhea
headaches
myalgia
lack of appetite
constipation
stomach pains
in some cases, a rash of flat, rose-colored spots called "rose spots"

Extreme symptoms such as intestinal perforation or hemorrhage, delusions, and confusion also are possible

Diagnosis

Diagnosis is made by blood, bone marrow or stool cultures and with the Widal test (demonstration of salmonella antibodies against antigens O-somatic and H-flagellar) or, in less affluent countries with the urine diazo test. In epidemics and less wealthy countries, after excluding malaria, dysentery or pneumonia, a therapeutic trial with chloramphenicol is generally undertaken while awaiting the results of Widal test and blood cultures.

Treatment

Typhoid fever can be fatal. Antibiotics, such as ampicillin, chloramphenicol, trimethoprim-sulfamethoxazole, and ciprofloxacin are commonly used in treating typhoid fever in the west.

When untreated, typhoid fever persists for three weeks to a month. Death occurs in between 10% and 30% of untreated cases. Vaccines for typhoid fever are available and are advised for persons traveling in regions where the disease is common (especially Asia, Africa, and Latin America).

Transmission

A person may become an asymptomatic carrier of typhoid fever, suffering no symptoms, but capable of infecting others. According to the Centers for Disease Control approximately 5% of people who contract typhoid continue to carry the disease after they recover.

The most notorious carrier of typhoid fever, but by no means the most destructive, was Mary Mallon, also known as Typhoid Mary. In 1907 she became the first American carrier to be identified and traced. She was a cook in New York at the beginning of the 20th Century. Some believe she was the source of infection for several hundred people. She is closely associated with fifty cases and five deaths. Public health authorities told Mary to give up working as a cook or have her gall bladder removed. Mary quit her job, but returned later under a false name. She was detained and quarantined after another typhoid outbreak. She died of a stroke after 23 years in quarantine.

Famous victims

Typhoid fever has touched the lives of several famous people.

Read more at Wikipedia.org

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First typhoid vaccine to protect children proven effective by NICHD scientists - Brief Article
From Medical Laboratory Observer, 6/1/01 by Celia Stevens

Scientists at the National Institute of Child Health and Human Development (NICHD) have developed and tested the first vaccine capable of protecting children from ages 2 to 5 against typhoid fever. Results of the study, conducted in Vietnam, appear in the April 26 New England Journal of Medicine. The effectiveness of the vaccine -- 91.5 percent -- is the highest reported for any typhoid vaccine.

Untreated, typhoid fever is a debilitating and life-threatening illness caused by the bacteria Salmonella typhi. Vaccine development for typhoid fever has been difficult because S. typhi inhabits and causes illness only in human beings -- there are no animal models for the disease. Typhoid fever is spread by fecal contamination of drinking water or food, or by person-to-person contact. The disease is common in developing countries lacking adequate sewage and sanitation facilities. Symptoms include fever, stomach pains, weight loss, loss of appetite, delirium, severe diarrhea (in children), and constipation (in adults).

According to the U.S. Centers for Disease Control and Prevention, about 16 million people worldwide develop typhoid each year, and 600,000 die from it. Roughly 400 cases of typhoid fever occur in the U.S. each year, about 70 percent of which are acquired by Americans traveling abroad.

The NICHD researchers conducted the study in the Dong Thap province of the Mekong Delta, a rural area that lacks a public sewage system and therefore has a high incidence of typhoid fever -- roughly 413 cases for every 100,000 children under age 15. More than 90 percent of the typhoid strains present in the area are resistant to the antibiotics used to treat the disease.

In developing the vaccine, the NICHD researchers used an approach they had earlier pioneered. The approach involves chemically linking a polysaccharide from the disease-causing bacteria with a protein molecule. Ordinarily, the polysaccharide would slip past the defenses of a child's immature immune system, but adding the protein to the polysaccharide allows the immune system to produce antibodies that inactivate the bacteria.

Antibodies are immune system proteins that recognize a particular substance. Together with another protein called complement, antibodies begin the first steps in the complex sequences of events by which the immune system destroys disease-causing organisms.

In all, 11,091 Vietnamese children ranging from age 2 to age 5 took part in the study. The children received two injections, six weeks apart. Half received the vaccine, and the other half, a placebo. Over the next two years, their physicians observed both groups. Those who developed typhoid fever received the standard treatment of antibiotic therapy for the disease.

S. typhi was isolated from only four children who had received both injections of the vaccine. The placebo group had 47 cases, for an effectiveness rate of 91.5 percent. By comparison, typhoid vaccines currently on the market have a 70% effectiveness rate and do not protect children under age 5 against the disease. Fewer than 2% of children experienced any side effects, all of which were mild and limited to swelling at the injection site or to mild fever that resolved within 48 hours.

The study authors next plan to test the vaccine in children under 2 to see if it can be administered at the same time as the routine vaccination for diphtheria, tetanus, and pertussis. According to the authors, because of the high levels of protective antibodies brought about in young children by the vaccine, it would probably be at least 90% effective in individuals above 5 years of age, including military personnel and travelers to areas with high rates of typhoid fever

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