Scrub Typhus - Causes, Symptoms, and Treatment

Introduction:

Typhus fevers are caused by bacteria that are spread to humans by lice, fleas, and chiggers. It includes murine typhus, scrub typhus, and epidemic typhus. Fleas spread murine typhus, epidemic typhus by body lice, and chiggers spread scrub typhus. These are commonly characterized by fever, headaches, and sometimes rashes. Scrub typhus was first described in 313 AD in China. The name derives from the type of vegetation that harbors the vector (terrain between woods and clearings). However, scrub typhus can also be prevalent in sandy beaches, equatorial rainforests, and mountain deserts.

What Is Scrub Typhus?

Scrub typhus, also called bush typhus, is a bacterial infection spread through the bites of infected chiggers (larval mites). According to current estimates, one million scrub typhus cases occur annually, with most cases occurring in rural areas of Southeast Asia, Indonesia, Japan, India, China, and northern Australia.

What Causes Scrub Typhus?

Scrub typhus is an illness caused by a bacteria called Orientia tsutsugamushi that is spread through infected mites that feed on rodents. This bacteria is found throughout the mite’s body but is present more in the salivary glands.

How Is Scrub Typhus Spread?

The illness is spread through infected larval mites; found in heavy scrub vegetation areas. Leptotrombidium akamushi and Leptotrombidium deliense mites are the primary vectors of Orientia tsutsugamushi. These mites inhabit many habitats, including plantations, beaches, forests, and gardens. They feed on small mammals, especially rodents, to complete their life cycle. Humans usually are accidental hosts. The mites feed on rodents and humans and transmit the parasites to the hosts. The bacteria are found in more significant numbers in the salivary glands of the chiggers. It spreads to the host through the saliva when the chiggers bite.

Who Is at Risk of Scrub Typhus?

People exposed to areas with scrub vegetation where rodents live, like forest clearings, rain forests, riverbanks, deserts, and grassy areas, are at risk of contracting the disease. In addition, people traveling to regions with an outbreak of scrub typhus are also at risk of the disease.

What Are the Signs And Symptoms of Scrub Typhus?

The signs and symptoms of scrub typhus usually appear within ten days of being bitten by the infected mite. The symptoms of scrub typhus may include:

• Headache.

• Fever.

• Chills.

• Body ache.

• Muscle pain.

• Eschar formation (at the site of the chigger bite, a dark, scab-like region is developed).

• Confusions.

• Lymphadenopathy.

• Plantar and palmar erythema.

• Maculopapular rashes.

• Mental changes and disorientation.

• Coma.

If the disease progresses severely, the person may develop organ failure, bleeding, and death if left untreated.

How to Diagnose Scrub Typhus?

Diagnosis of scrub typhus could be difficult since the symptoms of the illness are similar to symptoms of many other conditions. Hence, contact the healthcare provider if one develops the symptoms listed above. The healthcare provider will need a travel history to check if the person has traveled to places where scrub typhus is prevalent. A blood test is used to detect antibodies to the bacteria that cause scrub typhus. If antibodies are found, it confirms the person has scrub typhus. The laboratory testing and reporting of results can take several weeks, so it is advised to start treatment before the reports are available.

Other tests that can help diagnose scrub fever include:

• Antibody-based rapid diagnostic field tests.

Polymerase chain reaction (PCR) test.

• Cell culture of the scab sample.

What Is the Treatment for Scrub Typhus?

Doxycycline is a Tetracycline antibiotic that is effective against many infections, including scrub typhus. It can be used for people of any age and is available as a tablet or capsule. Antibiotics are effective against scrub typhus if given as soon as the symptoms begin. Hence, people who are treated early usually recover quickly. A seven-day regimen of antibiotics is often adequate unless the condition is severe. The second-line treatment option for scrub typhus is Chloramphenicol.

What Are the Complications of Scrub Typhus?

Scrub typhus is usually a mild infection that resolves with proper treatment with antibiotics. However, if a systemic involvement occurs, it may lead to severe complications, including:

• Pneumonia.

• Acute renal failure.

• Hypotension.

• Meningoencephalitis.

The mortality rate of people associated with scrub typhus may be as high as 60 percent in untreated cases. However, the symptoms start to improve within 48 hours if appropriate and timely treatment is given. The patient may recover entirely in seven to ten days.

How to Prevent Scrub Typhus?

Preventing the infection is the best option one can take. However, since no vaccines are available to prevent scrub typhus, precautions must be taken to avoid being bitten by mites. This include:

• Refrain from traveling to places with an outbreak of scrub typhus.

• Stay away from places where mites are usually found, including sites with thick vegetation.

• Wear long-sleeved shirts and pants when in a mite-prone area.

• When spending time outdoors, use an EPA (environmental protection agency) - registered insect repellent containing DEET (N, N-diethyl-meta-toluamide) or other ingredients against chiggers. Use the insect repellents as directed by the manufacturer; do not use them on the skin covered by clothing.

• Cover the legs and arms of babies and young children. If the child is in a crib or stroller, use a mosquito net and drape over it to prevent the entry of mites.

• Be cautious when using insect repellents on children; ensure that they do not come in contact with the mouth, eyes, or open wounds.

• Use 0.5 percent permethrin to treat clothing and gear or buy permethrin-treated items. Permethrin helps kill chiggers and can be used to treat boots, camping gear, and apparel. Follow the instructions as provided by the manufacturer, and do not use permethrin directly on the skin.

Conclusion:

Scrub typhus is a bacterial infection spread by larval mites. It is a mild infection if appropriate treatment is taken in the early stages. A person could acquire complete recovery within seven to ten days with the help of antibiotics. However, the immunity to the illness is short-lived and strain-specific, so getting a further infection after recovery is possible. Consult the healthcare professional immediately if one suspects symptoms of scrub typhus.