Scrub typhus is an infectious Rickettsial disease caused by a bacterium which is transmitted through the bite of infected mites. If not properly managed, it can lead to severe complications including death.

Scrub typhus has a long history, with descriptions of similar diseases appearing in medical literature as early as the 19th century. The term “scrub” refers to the type of vegetation where the disease is commonly found, such as shrubs and dense underbrush. The bacteria responsible for the disease were first isolated during World War II, revealing its potential to affect military personnel in tropical climates.

• Causative Agent: It is caused by bacteria Orientia tsutsugamushi

• Vectors: Infected Larval Mites (Chiggers) – Larvae of Trombiculidae mites. Larvae are small and hardly visible to naked eye. These larvae feed on our skin.

• How do they reach you: Chiggers live on grass or moist wooded areas. It may stick to your cloth or directly to skin.

• Common sites of Chigger bites: Ankles or lower leg, waist, groin, behind knees.

• Endemic Areas: Southern Asia, Northern Australia, Islands of Indian and Pacific Ocean.

• Incubation Period: 9-18 days

• Disease Range: Mild or Self Limiting to Fatal.

• Common symptoms: Fever, Headache, Myalgia, Cough and Gastrointestinal Symptoms

• Classic signs: Lymphadenopathy (Enlarged lymph node); Maculopapular Rash and Eschar formation (40 – 50% of Cases). Eschar is dark, scab like lesion at site of infected larval bite.

• Severe disease: Confusion, Coma, Encephalitis and Interstitial Pneumonia.

• Case fatality Rate of Untreated Classic Cases: 7%

• Diagnosis: Serologic assays (Indirect Fluorescent Antibody; Indirect Immuno-peroxidase and enzyme Immunoassays). Polymerase Chain Reaction (PCR) – sample from blood or eschar

• Management: Topical lotions. Antihistaminic. Cold compress over bite area. Symptomatic along with some antibiotics (eg: Doxycycline, Azithromycin, Chloramphenicol, Rifampin); Severe case may require intensive care followed by Rehabilitation.

•Prevention

∗ Wearing proper and protective clothing covering arm and feet when outside (especially in Endemic areas)

∗ Mites’ repellent can be used

∗ If you are camping – Treat clothing/gear with 0.5% permethrin. Treated clothing is protective even after multiple washings.