Scrub typhus

Scrub typhus, also called bush typhus, is an infection caused by a bacterium called Orientia tsutsugamushi. It spreads to people through the bite of chiggers, the tiny young stage of certain mites that live in grass and scrub. It is not the same illness as typhoid fever.

It occurs mainly in rural parts of Asia, including India, where it is a known cause of fever that is often not recognised early. Treated early with the right antibiotic, most people recover quickly.

Symptoms usually begin suddenly, within about 10 days of the bite. They can include:

• Fever with chills
• Headache
• Body and muscle aches
• A dark, scab-like spot (eschar) where the mite bit, often in a skin fold such as the armpit, groin or under the breast
• Swollen glands
• Cough or breathlessness
• A rash, in some people
• Confusion, in more serious illness

Not everyone has the scab-like spot. Without treatment the fever may last two to three weeks, and serious problems usually appear after the first week.

See a doctor soon for any fever that does not settle within a few days, especially after time in fields, grass or bush, or if you find a dark scab-like spot. Say where you have been. Treatment works best when started early.

Scrub typhus is caused by the bacterium Orientia tsutsugamushi. Chiggers carry it and pass it on when they bite. Chiggers are the larval stage of mites and live in areas of thick grass, bush and scrub, mostly in the countryside.

• Living in or visiting rural areas with thick grass, bush or scrub
• Outdoor work or leisure in grassy or bushy places
• Bare arms and legs, and no repellent, in those places
• Pregnancy, when the illness can harm the pregnancy
• Delay in treatment, which is the main reason it becomes severe

Most people recover quickly once treated. Without treatment, or when treatment is late, scrub typhus can cause:

• Pneumonia and severe breathing trouble
• Inflammation of the brain or its lining, causing confusion or coma
• Kidney failure, liver damage and jaundice
• Bleeding
• A dangerous fall in blood pressure (shock) and failure of several organs
• Loss of the pregnancy
• Death

There is no vaccine. Avoiding chigger bites is the way to lower the risk:

• Avoid thick grass, bush and scrub where you can
• In such places, wear long sleeves, trousers and closed shoes
• Use a repellent that works against chiggers, such as one containing DEET, on skin and clothing, and follow the label
• Never put repellent on a child's hands, eyes, mouth or broken skin
• Clothing can be treated with permethrin, which must never be put on the skin

Doctors suspect scrub typhus from the fever, from where the person has been and from findings such as the eschar. No quick, reliable test is available early in the illness, so treatment is not held back for results. Blood tests may show a low platelet count and raised liver enzymes, which also happen in other fevers.

Antibody tests (IgM ELISA) and PCR on blood can confirm the diagnosis.

Antibiotics are the treatment, and doctors start them as soon as scrub typhus is suspected, without waiting for test results. Doxycycline is the usual first choice and can be used at any age. Pregnant women are usually given a different antibiotic, such as azithromycin.

The full course should be completed, because a course that is too short can let the illness return. People with breathing trouble, confusion, bleeding, or kidney or liver involvement need hospital care, with antibiotics by drip, oxygen and support for any failing organ.