Where is it found?
Scrub typhus is mainly found in the ‘tsutsugamushi triangle’, an area covering parts of Japan, the Philippines, northern Australia, India, Pakistan, Afghanistan, and southern Russia. Around one billion people are at risk of scrub typhus, and there are an estimated one million cases every year. The risk of death can be up to 50%.
The World Health Organization has cautioned that the disease is emerging as a public health problem in rural Southeast Asia, particularly in Myanmar, Indonesia, Thailand, India, Pakistan, Maldives, Sri Lanka, and Nepal. There is therefore a need for enhanced surveillance, early diagnosis, effective treatment, and preventive strategies to control the disease.
What are the symptoms of scrub typhus?
Symptoms generally appear 10-12 days after the bite, and include:
- Fever
- Severe headache
- Vomiting
- Drowsiness
- Congested eyes
- Cough
- Muscle pain
- Shin pain
- Deafness
- Enlargement of liver and spleen
- Meningoencephalitis occurs in approximately 5% of cases. As the disease progress to meningoencephalitis, other symptoms which develop include:
- Altered sensorium
- Neck stiffness
- Seizures
The characteristic sign, called ‘eschar’, is a blackish ulcer found at the feeding site of the mite, mainly in the groin, armpits, genitalia, and neck.
How is it diagnosed?
Diagnosis of scrub typhus encephalitis is made by brain scan (MRI/CT scan) and lumbar puncture. A lumbar puncture is conducted by inserting a needle in between vertebrae and withdrawing cerebrospinal fluid (CSF) which circulates around the brain and spinal cord.
Diagnosis is confirmed by evidence of bleeding, raised levels of inflammatory cells, elevated antibodies against Orientia tsutsugamushi, and polymerase chain reaction (PCR) detection of Orientia tsutsugamushi in the CSF.
How is it treated?
The illness can be treated by administering an easily available antibiotic called Doxycycline. Severely ill people require hospitalisation, intensive care, anti-seizure medications for control of seizures, and administration of intravenous fluids. They also need to be closely monitored for complications such as seizures, brain swelling, electrolyte imbalance, abnormal breathing, and choking.
How can it be prevented?
The first step towards prevention is to reduce exposure to mites. It is important to wear protective clothing, such as long sleeves, long trousers, and closed shoes when visiting areas where this infectious disease is endemic. Applying insect repellents containing DEET onto skin and clothing can also help prevent infection.
If possible, one must avoid known endemic areas and avoid sitting or lying directly on grassy or bushy areas. New settlements after clearing forests, riverbanks, and grassy areas have been observed to provide suitable settings for infected mites to cause disease transmission.
By Dr Amod Rayamajhi, Bassett Medical Center, Cooperstown, New York, USA; and Dr Ajit Rayamajhi, National Academy of Medical Science, Kanti Children’s Hospital, Kathmandu, Nepal
FS081V1 Scrub typhus encephalitis
Date created: April 2025 / Last updated: May 2025 / Review date: May 2028
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