The Chinese idiom “Hope that you are free from scrub typhus” (別來無恙) is a greeting for health. As early as the Jin dynasty, Ge Hong had mentioned that the illness was prevalent in southern China, which was called the sand louse fever.

Scrub typhus, also known as bush typhus, is a febrile or exanthematous illness transmitted by "tsutsugamushi" and carries Orientia tsutsugamushi. An acute febrile ailment in which the host is infected with rickettsia after being bitten by the tsutsugamushi through its saliva. Rats are the most common hosts of scrub typhus.

Etiology

• Specifically, scrub typhus is transmitted mainly through certain species of tsutsugamushi, especially Leptotrombidium deliense, or sand flea, which lives mainly in dense shrub vegetation. Other related varieties include L. akamushi, L. arenicola, L. fletcheri, L. pallidum, and L. pavlovsky. Once bitten, the tsutsugamushi leaves a distinctive black eschar on the skin, useful for doctors to diagnose.

Clinical Symptoms

• Sudden, persistent high fever (39°C), headache, back pain, chills, night sweats, enlarged lymph nodes, red maculopapular rashes on the skin one week later, and sometimes with pneumonia. A painless eschar appears on the bite of the tsutsugamushi.
• The incubation period is usually 9-12 days, and about 50-80% of patients can find a black, ulcerative eschar at the bite of the tsutsugamushi, mostly painless, as well as local "lymph gland inflammation and enlargement."
• Red maculopapular rashes appear on the trunk 4-5 days after fever, and then spread to the limbs and face. The symptom subsides 9 or 10 days later; headache or muscle pain, excessive sweating, conjunctival congestion, cough and gastrointestinal problems.

Complications

• Without proper treatment, severe bleeding or intravascular coagulation may lead to decreased blood pressure, unconsciousness, pneumonia, encephalitis, myocarditis and other complications, or shock, with a mortality rate of 1-60%.

Prevention

• The tsutsugamushi likes to grow on wet soil and on the tip of weeds. According to the statistics of the Ministry of Health and Welfare, more than 2,000 cases of scrub typhus have been confirmed in Taiwan over the past five years. When people go outdoors or travel in high temperatures or after rain, they should avoid entering the grassy areas, and should wear long-sleeved tops and pants or apply insect repellents when necessary, so as to avoid being bitten. Seeak medical attention immediately if fever persists for 3 days.