Epidemic typhus is a rickettsial disease that is caused by Rickettsia prowazekii and spread by body lice and occasionally through contact with flying squirrels.
People with epidemic typhus have a fever, an intense headache, and extreme exhaustion, followed by a rash 4 to 6 days later.
To diagnose the infection, doctors test a sample of the rash and sometimes do blood tests.
Epidemic typhus is treated with an antibiotic.
Washing and drying infested clothes at high temperatures can help prevent the spread of infection.
Rickettsiae are a type of bacteria that can live only inside the cells of other organisms. The rickettsiae that cause epidemic typhus typically live in people (the host). But in North America, these rickettsiae can also live in flying squirrels.
Epidemic typhus occurs throughout the world. The infection is usually transmitted by body lice when their feces enters the body through breaks in the skin or sometimes through mucus membranes of the eyes or mouth. In the United States, people occasionally develop epidemic typhus after coming into contact with flying squirrels.
This infection is called epidemic typhus because in the past, it has caused large outbreaks (epidemics) that killed large numbers of people. Such outbreaks are now rare, but smaller ones have recently occurred in Africa. Epidemic typhus spreads most easily in crowded, unhygienic conditions as occur during war or civil unrest or in areas of extreme poverty.
Symptoms of Epidemic Typhus
Symptoms of epidemic typhus begin suddenly about 7 to 14 days after bacteria enter the body. People have a fever and an intense headache and feel very tired. A rash appears 4 to 6 days later. The rash usually begins on the chest and spreads to the arms, and legs.
Sometimes the spleen enlarges. If the infection is severe, blood pressure may become very low, the kidneys may malfunction, and gangrene and/or pneumonia may develop.
Untreated, epidemic typhus may be fatal; the risk of fatality increases with age.
Diagnosis of Epidemic Typhus
A doctor's evaluation
Biopsy and testing of the rash
Blood tests
The diagnosis of epidemic typhus is suggested by the symptoms, particularly if the person has body lice or has been in an area where there was an outbreak of typhus.
To confirm the diagnosis, doctors may do an immunofluorescence assay, which uses a sample taken from the rash (biopsy). Or they may use the polymerase chain reaction (PCR) technique to enable them to detect the bacteria more rapidly.
Doctors may do blood tests that detect antibodies to the bacteria. However, doing the test once is not enough. The test must be repeated 1 to 3 weeks later to check for an increase in the antibody level. Thus, antibody tests do not help doctors diagnose the infection immediately after someone becomes ill but can help confirm the diagnosis later.
Treatment of Epidemic Typhus
Prevention of Epidemic Typhus
Measures to control lice can help prevent the infection from spreading. For example, louse-infested clothing and bedding should be washed with hot water and dried with high heat or be dry cleaned. Also, people should avoid contact with flying squirrels and their nests.
Brill-Zinsser Disease
Brill-Zinsser disease is a recurrence of epidemic typhus, sometimes years after the first infection.
Some of the organisms that cause epidemic typhus remain in the body. They may become reactivated if a person's immune system is weakened.
Symptoms of Brill-Zinsser disease are almost always mild and resemble those of epidemic typhus. The fever lasts about 7 to 10 days. People may not have a rash.
Diagnosis and treatment of Brill-Zinsser disease are similar to those of epidemic typhus.
