Introduction:
Scrub typhus is a mite-borne disease. Scrub typhus can be observed in areas like Asia-Pacific bounded by Japan, Korea, China, India, and Northern Australia. Scrub typhus was first described in 313 AD in China. Scrub typhus is also called bush typhus. According to current estimates, one million scrub typhus cases occur annually.
What Is Scrub Typhus?
Scrub typhus is a condition caused by a bacteria. The bacteria is Orientia tsutsugamushi. This is related to rickettsial diseases (infections are caused by unusual types that can live only inside the cells of another organism) of bacteria. O. tsutsugamushi is transmitted by trombiculid mite larvae (chiggers). Human infections occur due to chigger bite.
The name scrub typhus was derived from the vegetation (ie, the terrain between woods and clearings) that contains the vector. This can be treated effectively if detected early. The clinical manifestations may vary from asymptomatic to severe disease. The mortality rate varies and it may be up to 50 percent.
This organism can affect vascular endothelium and mononuclear macrophages. Scrub typhus does not affect people from person to person but is transmitted by vector bites. The vector is the chigger of the trombiculid mite belonging to the genus Leptotrombidium. The vector activity may depend on the temperature, rainfall, land use, and various socioeconomic factors.
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.
O. tsutsugamushi is an obligate intracellular gram-negative bacteria. This bacteria lives in L akamushi, and L deliense mites. When the mites feed on rodents or humans, parasites are transmitted to the host. It was found that only larval Leptotrombidium mites (chiggers) can transmit the disease. Chiggers transmit scrub typhus to humans when they bite the skin. Chigger bites appear to be itchy red bumps that look like pimples, blisters, or small hives. They were found to appear to be in groups.
How Is Scrub Typhus Spread?
The illness is spread through infected larval mites, which are found in heavily 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. Humans are usually 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 Symptoms of Scrub Typhus?
The symptoms of scrub typhus usually appear within ten days of being bitten by the infected mite. The symptoms of scrub typhus may include:
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Fever.
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Chills.
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Body ache.
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Muscle pain.
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Eschar formation (at the site of the chigger bite, a dark, scab-like region is developed).
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Confusions.
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Lymphadenopathy.
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Plantar and palmar erythema.
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Maculopapular rashes.
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Mental changes and disorientation.
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Coma.
Individuals affected by scrub typhus develop a rash. The rash develops as a red, indurated lesion. It then vesiculates, ruptures, and is then covered with a black scab.
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, one should 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 typhus include:
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Antibody-based rapid diagnostic field tests.
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Polymerase chain reaction (PCR) test.
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Cell culture of the scab sample.
What Is the Treatment for Scrub Typhus?
The treatment of scrub typhus can be done by antibiotic therapy.
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Doxycycline is a Tetracycline antibiotic. This is effective against many infections, including scrub typhus. Doxycycline 100 mg to be taken twice per day for one week.
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Macrolides like Azithromycin, Roxithromycin, and Telithromycin can be used to treat.
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Fluoroquinolones were used, but they are not currently recommended.
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In severe cases, supportive management is necessary.
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.
Doxycycline may cause sensitive skin to sun exposure. It may cause skin rash, itching, redness, or discoloration of the skin or a severe sunburn.
Chiggers rash treatment include:
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Chigger bites or rashes should be washed with soap and water to remove any chiggers attached.
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A cool cloth may be held on the chigger bites to soothe.
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The application of anti-itch cream may help.
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:
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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.
Scrub typhus may be dangerous because if scrub typhus is not treated appropriately, it may be fatal. It may cause organ damage and severe bleeding too.
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 includes:
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Refrain from traveling to places with an outbreak of scrub typhus.
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Stay away from places where mites are usually found, including sites with thick vegetation.
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Wear long-sleeved shirts and pants when in a mite-prone area.
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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.
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Cover the legs and arms of babies and young children. If the child is in a crib or stroller, drape a mosquito net over it to prevent mites from entering.
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Be cautious when using insect repellents on children; ensure that they do not come in contact with the mouth, eyes, or open wounds.
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Permethrin of 0.5 percent is used. This helps 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.
Conclusion:
Scrub typhus is a bacterial infection spread by larval mites. It is mild if appropriate treatment is taken in the early stages. With antibiotics, a person could complete recovery within seven to ten days. However, 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.
