Scrub Typhus: A Chigger-Borne Infection of Rural Asia and the Pacific

Key points

• Scrub typhus spreads through bites of infected chiggers (larval mites).
• Symptoms include fever, chills, headache, body aches, a scab-like spot at the bite (eschar), mental changes, enlarged lymph nodes and rash.
• It's treated with doxycycline, which works best when given early.
• Most cases occur in rural Southeast Asia, Indonesia, China, Japan, the Indian subcontinent and northern Australia.

What it is

Scrub typhus, or bush typhus, is caused by the bacterium Orientia tsutsugamushi. Anyone living in or traveling to places where it occurs can be infected.

Signs and symptoms

Symptoms usually begin within 10 days of infection:

• fever and chills;
• headache;
• body aches and muscle pain;
• a dark, scab-like eschar at the bite;
• mental changes, from confusion to coma;
• enlarged lymph nodes;
• rash.

Untreated, it can be fatal, causing organ damage and severe bleeding.

An eschar at the site of a chigger bite. CDC.

Prevention

There is no vaccine. Avoid chiggers: where scrub typhus is common, stay away from areas with dense vegetation and brush. Outdoors:

• Repellent: use an EPA-registered repellent with DEET or another ingredient registered against chiggers, on exposed skin and clothing; look for an EPA registration number on the label; follow instructions and reapply as directed; put on sunscreen first.
• Children: dress them in clothes that cover arms and legs; don't put repellent on their hands, eyes, mouth, or on cuts or irritated skin — spray it on your hands and apply it to the child's face.
• Permethrin: treat boots, clothing and camping gear with 0.5% permethrin, or buy treated items. It kills chiggers and lasts through several washings. Never put permethrin on skin.

Adult and larval chiggers on a pinhead — they are tiny. CDC.

Diagnosis

Its symptoms resemble many other diseases. If you get sick after being where scrub typhus occurs, see a provider and say where and when you traveled. Blood tests can help, but results can take weeks, so treatment may start before they arrive.

Treatment

• Doxycycline, for patients of any age.
• Antibiotics work best soon after symptoms begin; people treated early usually recover quickly.

Sources

Based on "About Scrub Typhus," Centers for Disease Control and Prevention; a work of the United States government in the public domain. A stock photograph is left out.