Scrub Typhus

Excerpt

Scrub typhus is an infectious disease caused by the rickettsial bacterium Orientia tsutsugamushi. The causative organism displays high levels of antigenic variation. It is a serious public health problem in the Asia-Pacific region including but not limited to the region known as the “tsutsugamushi triangle”. One billion people globally covering more than 8 million kilometers from Pakistan in the west, Australia in the south, and Japan in the east are threatened by this infection which can be fatal at times.

A systemic review on the burden of scrub typhus in India which is in the “tsutsugamushi triangle” revealed that that scrub typhus accounts for at least 25.3% among individuals with acute undifferentiated febrile illness (AUFI). Despite being one of the commonest pathogens of the cause of such commonly encountered illness, it remains a neglected disease in terms of research and formulation of health care policies.

It is transmitted to humans by the bite of the larva of trombiculid mites. Later it causes disseminated vasculitis and perivascular inflammation ultimately leading to significant vascular leakage leading to end-organ injury. The disease can affect people of all ages and travelers across the globe who have visited regions of endemicity.

Clinical features usually arise after an incubation period of 6-21 days and manifest as fever, headache, myalgia, and gastrointestinal symptoms. An eschar which usually begins as a primary papular lesion later crusts to form a black ulcer with central necrosis is a distinct feature of scrub typhus although its presence varies in different regions.

The decision to initiate treatment should be based on clinical suspicion and later confirmed by serological tests.