1.Eschars and estate fever A case series from the Johorean oil palm heartland highlighting the changing face of scrub typhus in Malaysia
Yew B.T. ; Nathanael L.Y.S. ; Yahya N.H.
Tropical Biomedicine 2026;43(No. 1):65-75
Scrub typhus, a zoonotic bacterial infection caused by the arthropod-borne, Gram-negative, obligate
intracellular bacillus Orientia tsutsugamushi and transmitted by larval chiggers, is an underdiagnosed
cause of acute undifferentiated febrile illness. Its clinical spectrum ranges from a self-limited denguelike illness to rapidly progressive multiorgan dysfunction driven by smallvessel vasculitis, including
pneumonitis, acute kidney injury, hepatitis, encephalitis and circulatory shock. Early recognition is
frequently missed because the characteristic eschar may be absent or easily overlooked in concealed
or pigmented skin sites, and definitive diagnostics such as polymerase chain reaction (PCR) or indirect
immunofluorescence assay (IFA) are often unavailable in resource-limited settings. Occupational and
environmental exposures, particularly work in oil palm or rubber plantations and contact with forest–
estate ecozones, remain key epidemiological clues that may be under-elicited in routine clinical practice.
We report a case series of four patients with confirmed scrub typhus presenting to a hospital in Kluang
district, Johor, Malaysia. All patients had acute fever and non-specific viral-like symptoms, including
malaise, chills, headache and myalgia. Thrombocytopenia and acute kidney injury occurred in 50%,
while 75% demonstrated transaminitis. Eschars were identified in all patients following comprehensive
dermatological examination. Diagnosis was confirmed by PCR for O. tsutsugamushi DNA, a fourfold rise
in IFA titres, or a single high-titre IgM or IgG in a compatible clinical syndrome. Three patients (75%)
had clear domiciliary or occupational risk factors, including oil palm work or residence near secondary
scrubland. One patient developed organ-threatening complications with acute kidney injury and severe
hepatitis, illustrating the vasculitic end-organ involvement of severe scrub typhus. All patients achieved
clinical defervescence and symptomatic improvement within 24–48 hours of doxycycline initiation,
consistent with the characteristic brisk antimicrobial response. This series underscores the need for a
low threshold of clinical suspicion and early empiric rickettsial coverage in undifferentiated febrile illness
with relevant exposure in rural Malaysia and highlights the need for larger multicentre studies to define
predictors of severity, guide triage and inform prevention in high-risk land-use settings.


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