Scrub Typhus

Scrub typhus in a commonly encountered illness, especially in those staying or traveling in eastern Asia countries.

The disease often goes undiagnosed because of its presentation resembling common viral illness.

What is Scrub Typhus?

This is basically a bacterial infection. It is caused by a bacteria called Orientia tsutsugamushi.

This bacteria cannot infect a human directly, and needs a vector, that is, a third party to participate in infection causation.

There is a mite called trombiculid. This one lives in bushes, and is commonly present in east Asian countries.

When the mite carrying the causative bacteria bites you, the bacteria gets into your blood stream. It then establishes itself and multiplies in number, to give a full blown picture of the disease.


Chigger Bite

A chigger bite is often diagnostic. This is the site where the mite has bitten you to instill the infection.

Typically, the bite is a central area of necrosis, surrounded by redness all over. The central area may slowly scab away.

The site is usually painless and there’s no symptom, like itching etc., over it. This is the reason why it often goes unnoticed.

Flu Symptoms

Flu like symptoms, like high fever, chills, general weakness are often present. This happens as the bacteria flows in your blood stream, provoking your immune cells.

There may be enlarged lymph nodes. This is common in the regional area, where you have the bite. However,  generalized lymphadenapathy may also be seen. That is, many different lymph nodes of the body get affected, and are enlarged.


Red rashes over the body may be seen. These are painless raised areas. These rashes may show eschar formation.

This means that the rash would slowly necrose or decay from its center. A scab may get formed there.

Other Signs

  • A recent travel to any east Asian country is a possibility. The infection may have a small incubation period of around 15 to 20 days.
  • You may have cough with fever.
  • Sometimes, tiny hemorrhages are noted, as in mucosal regions, like your eye. These are conjunctival hemorrhages. You may feel some eye pain.


If not detected on time, the bacteria grows and multiplies in large quantities. It may start affecting your major organs, including your heart, lungs or kidneys.

In such cases, cardiac involvement may be seen. Kidney function may become impaired, leading to renal failure in extreme cases.

It is therefore, why a patient of scrub typhus may become delirious.

DIC (disseminated intravascular coagulation) is a serious condition in which clots keep getting formed inside the blood vessels on their own. This condition may be elicited by certian injuries or strong infection.

Scrub typhus is one of such infections, that may lead to DIC. The patient may present with shock like symptoms.

How to diagnose?

  • Weil Felix test is still the most widely used test for scrub typhus. It involves detecting the bacterial antigen in your blood stream directly.
  • If your symptoms and signs, like the chigger bite or rashes point towards this disease, your doctor may consider getting some blood work done.
  • Commonly, lymphocytes are raised, with altered CD4/ CD8 ratio. This means that killer Tcells are more than the Helper ones, indicating an active war going on in your body.
  • Platelet counts may be reduced.

Confusion With Viral Illnesses

Flu like symptoms, rashes and a low platelet count is commonly seen with viral infections. So, diagnosing scrub typhus may be difficult.

However, one needs to be prompt in detection. This is so because, not detecting early may give the bacteria a chance to multiply easily and lead to serious complications.


Antibiotics to kill the bacteria effectively are given.

Tetracyclines and Macrolide groups are the main stay. Most popular drugs incrude doxycycline or Azithromycin.

Supportive care with adequate rest is a must.


  • Use of mosquito repellents to prevent the vector mite from reaching you.
  • Covering yourself with clothes
  • Keep your surroundings clean, trimming the vegetation from time to time.

Visit to Any Endemic Country

Take all preventive measures as mentioned above.

A single dose of doxycycline given weekly may be started, and continued for 6 weeks after exposure.

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