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Scrub Typhus

(Tsutsugamushi Disease; Mite-Borne Typhus; Tropical Typhus)

By

William A. Petri, Jr

, MD, PhD, University of Virginia School of Medicine

Last full review/revision Jul 2020| Content last modified Jul 2020
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Topic Resources

Scrub typhus is related to rickettsial diseases and is caused by Orientia tsutsugamushi. It is spread by chiggers (mite larvae).

  • People with scrub typhus have a fever, chills, and a headache, followed by a rash several days later.

  • To diagnose the infection, doctors test a sample of the rash and sometimes do blood tests.

  • Scrub typhus is treated with an antibiotic.

The bacteria that cause scrub typhus, like rickettsiae, can live only inside the cells of other organisms. Scrub typhus bacteria live in mites (the host).

Scrub typhus occurs in Japan, Korea, China, India, and northern Australia. The disease is transmitted to people when they are bitten by a chigger (mite larva).

Symptoms

Symptoms of scrub typhus begin suddenly, about 6 to 21 days after the bacteria enter the body. They include fever, chills, a headache, and swollen lymph nodes. A black scab may develop at the site of the chigger bite. People may have a cough during the first week of fever. A rash appears about 5 to 8 days after the fever starts.

Diagnosis

  • A doctor's evaluation

  • Biopsy and testing of the rash

  • Blood tests

The diagnosis of scrub typhus is suggested by symptoms in people who have recently been to an area where scrub typhus is common (such as Central Asia, southeast Asia, South Asia, and northern Australia) and have participated in outdoor activities, such as camping or visiting farms, which could expose them to chigger bites.

To confirm the diagnosis, doctors may do an immunofluorescence assay, which uses a sample 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, these tests do not help doctors diagnose the infection immediately after someone becomes ill but can help confirm the diagnosis later.

Prevention

Prevention involves clearing brush and spraying infested areas with insecticides to eliminate or decrease the mite population.

If people are likely to come in contact with the chiggers, they should use insect repellents such as DEET (diethyltoluamide).

Treatment

  • An antibiotic

Treatment of scrub typhus usually consists of the antibiotic doxycycline, taken by mouth, People take this antibiotic until they improve and have had no fever for 48 hours, but they must take it for at least 7 days. With treatment, people recover quickly.

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