What is Typhoid Fever

Typhoid fever is a life-threatening illness caused by the bacterium Salmonella typhi.

Statistics on Typhoid Fever

In the United States about 400 cases occur each year, and 70% of these are acquired whilst traveling internationally. Typhoid fever is still common in the developing world, where it affects about 12.5 million persons each year. Typhoid fever is common in most parts of the world except in industrialized regions such as the United States, Canada, Western Europe, Australia, and Japan. Therefore, if you are traveling to the developing world, you should consider taking precautions. Over the past 10 years, travellers to Asia, Africa, and Latin America have been especially at risk.

Risk Factors for Typhoid Fever

Salmonella typhi lives only in humans. Persons with typhoid fever carry the bacteria in their bloodstream and intestinal tract. In addition, a small number of persons, called carriers, recover from typhoid fever but continue to carry the bacteria. Both ill persons and carriers shed Salmonella typhi in their feces (stool). You can get typhoid fever if you eat food or drink beverages that have been handled by a person who is shedding S. Typhi or if sewage contaminated with S. Typhi 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 likely to be contaminated with sewage. Once Salmonella typhi bacteria are eaten or drunk, they multiply and spread into the bloodstream. The body reacts with fever and other signs and symptoms.

Progression of Typhoid Fever

The incubation period of the disease is usually 10-14 days following ingestion of comtaminated food, milk or water. The onset is insidious, with a headache being a prominent symptom. The fever is remittent and gradually increases in severity in a stepwise fashion over 3-4 days. Cough, sore throat, and altered behaviour may also be present. Constipation is usually present initially and diarrhoea occurs late in the disease. Physical examination during the first week of the illness will reveal a toxic individual with relative bradycardia. Several signs can be elicited in the second week of the illness, such as an erythematous maculopapular rash that blanches (referred to as ‘rose spots’), visible on the upper abdomen and thorax, that lasts for 2-3 days. Splenomegaly will occur in approximately 75% of patients. Cervical lymphadenopathy, hepatosplenomegaly and right iliac fossa tenderness may also be present. Week three of the illness is the time when the majority of complications will occur. These include lobar pneumonia, haemolytic anaemia, meningitis, polyneuropathy, acute cholecystitis, urinary tract infection and osteomyelitis. Intestinal perforation and haemorrhage can also occur. The fourth week of the illness is generally characterised by a gradual return to health.

How is Typhoid Fever Diagnosed?

Typhoid fever is usually diagnosed via blood culture, where a sample of blood is taken from the patient and smeared on a culture plate, where, if infected, Salmonella typhi will grow. You may also be asked to provide a urine or stool sample to also be cultured.

Prognosis of Typhoid Fever

Without treatment, the illness generally lasts 3-4 weeks. Mortality rates due to the disease are between 12 and 30%.

How is Typhoid Fever Treated?

Fluid replacement, good nutrition and antibiotic treatment are essential. Prevention via vaccination, provision of safe drinking water, sanitary disposal of excreta and proper attention to hygeine when handling food.

Typhoid Fever References

  1. Centre for Disease Control and Prevention. Disease Information, Typhoid Fever. URL link
  2. Kumar, Parveen & Clark, Michael. 1999, Clinical Medicine, 4th Edition, WB Saunders, London.
  3. Oxford Handbook of Clinical Medicine 5th Edition.