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Dr Tri Wangrangsimakul

Dr Tri Wangrangsimakul

Podcast interview

Scrub typhus is an infection caused by Orientia tsutsugamushi, a bacteria transmitted by the bite of an infected chigger mite. Characterised by a variety of symptoms and a high mortality rate, scrub typhus is an underfunded, neglected tropical disease not even listed by the WHO. Better diagnostic tests and optimised treatments are being developed since no vaccine is currently available.

Tri Wangrangsimakul

BSc(hons) MB ChB DTM&H MRCP FRCPath


Research physician and DPhil Student

Chiangrai Clinical Research Unit

I am the head of the MORU-affiliated satellite tropical medicine research unit in Chiangrai, Thailand. It is situated in the most northern province of the country bordering Myanmar and Laos. The region's topography is a mixture of hilly and riverine habitats. The population comprises Thais as well as groups belonging to hilltribes and migrant workers from neigbouring countries. The mainstay of the local economy is agriculture, much of it rural and small scale.

Chiangrai is located in a region endemic for tropical rickettsioses with scrub typhus being a major cause of febrile illness. Although it remains easily treatable with available antibiotics, much of the morbidity and mortality from scrub typhus can be derived from delayed presentation, lack of recognition, and limited access to effective diagnostics. All these factors contribute to a significant health burden not only locally, but also to the wider Asia-Pacific region where it is estimated that a billion people are at risk. Furthermore, there remain uncertainties about the optimal treatment of scrub typhus in Chiangrai, an area where drug-resistant strains of Orientia tsutsugamushi, a Gram negative intracellular bacteria responsible for scrub typhus, were previously reported over 2 decades ago. This finding is yet to be validated and the underlying nature fully investigated.

There is currently no vaccine for scrub typhus. Immunity after an infection is short-lived and does not provide universal protection against all strains. Our understanding of the immune response to Orientia tsutsugamushi remains limited although work is underway to rectify this knowledge gap in both humans and non-human primates. In Chiangrai, we are currently studying the immune response to scrub typhus in children using novel immunoassays developed at MORU. Further work investigating the pathophysiological pathways of infection, the optimal treatment of scrub typhus, and the characterisation of drug resistant infections are also underway.

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