Scrub Typhus Fever Symptoms and Treatment

Scrub Typhus Fever

Scrub typhus is also known as Bush Typhus, as the insect that causes this disease are often found in bushes in moist areas.  Larva of chiggers (larval mites) are responsible for spreading of this disease. Adult chiggers don't bite as they feed on other insects. Only larva of chiggers, which are just 0.25 mm in length, are responsible for Scrub typhus Fever. The bite of this mite creates black dead tissues on the site of bite. 

Scrub typhus is a bacterial disease

Scrub typhus is caused by an intracellular parasite named Orientia tsutsugamushi. It is a Gram-negative α-proteobacterium of family Rickettsiaceae, which was identified in year 1930. This virus gets inserted inside the body through bites of larva of chiggers(larval mites).

Symptoms of Scrub Typhus

After the insect bite it takes around 10 days for early symptoms to appear.

Common Signs and Symptoms : 

• fever
• headache
• muscle pain
• cough
• gastrointestinal symptoms

Some typical symptoms that occur only among some people are : 

• Morbilliform rash (measles-like eruptions)
• eschar (dead tissue that sheds or falls off)
• splenomegaly (enlarged spleen)
• lymphadenopathies (swollen or enlarged lymph nodes)

Severe Signs and Symptoms : More virulent strains of bacteria Orientia tsutsugamushi cause 

• hemorrhaging (when a blood vessel erupts either inside or outside body)
• intravascular coagulation (abnormal blood clotting throughout the body's blood vessels)

Symptoms seen in early stages of scrub typhus are:

• Leukopenia (low count of white blood cells)
• Abnormal liver function test

Symptoms seen in late stages of scrub typhus are:

• Pneumonitis (inflammation of lung tissue)
• Encephalitis (inflammation of the active tissues of the brain)
• Myocarditis (inflammation of the heart muscle myocardium)
• Meningitis (inflammation of the protective membranes covering the brain and spinal cord)

Acute encephalitis syndrome due to scrub typhus are also noticed in some parts of south Asia.

Scrub Typhus Diagnosis and Treatment

Clinical symptoms of scrub typhus overlap with other infectious diseases such as dengue fever, paratyphoid, and pyrexia of unknown origin (PUO). It makes it harder to diagnose. But the bite of this mite creates black dead tissues (eschar) on the site of bite, which is a characteristic sign of this disease. If the site of bite is under clothes or if the skin color is dark then your physician can easily miss it. Usually the patient never tell about any insect bite as it don't pain and the insect itself is rarely visible to naked eye.

In most of the cases the blood culture often comes negative, but if the doctor suspects this disease then they treat it with chloramphenicol antibiotic.

Most commonly used drugs to treat scrub typhus are doxycycline or tetracycline and chloramphenicol. Only a doctor can correctly prescribe the correct drug depending on age, gender and symptoms of patient. Antibiotics have decreased the fatality rate of  scrub typhus from 4-40% to 2%.

Scrub Typhus Vaccine

Currently there is no vaccine for scrub typhus. An early attempt to make the vaccine was done in 1937 at United Kingdom, but its human trials were suspended in 1945. During world war-II several troops died due to scrub typhus, but as antibiotics were discovered in 1944, the vaccine development programs were suspended. 

How to save yourself from Scrub Typhus ?

Chiggers and their larva are usually found in vegetation. Rainy and moist places gives them an appropriate breeding environment. During rainy season, children should stay away from vegetation, especially bushes, where insects are found in more count. As we told earlier that there is no vaccine , but antibiotics are available to treat it effectively.

Note: The larva responsible for scrub typhus is usually less than 0.3 mm in length. It is found in different color shades like red, orange and yellow and mostly found in uncontrolled vegetation.