Scrub Typhus Epidemiology and Clinical Management

Scrub typhus is an acute febrile illness caused by the obligate intracellular bacterium Orientia tsutsugamushi. Transmitted by larval trombiculid mites (‘chiggers’), the disease is endemic throughout the Asia-Pacific ‘Tsutsugamushi Triangle’ and has emerging foci in South America and Africa. Estimates exceed one million cases per annum, with expanding geographic reach driven by environmental change, urban encroachment and increased human mobility. Clinical presentation is often non-specific: high fever, myalgia, headache and a characteristic eschar may occur, but absence of pathognomonic signs complicates diagnosis. Severe complications—meningoencephalitis, acute respiratory distress and multiorgan failure—contribute to substantial morbidity and mortality when treatment is delayed. Epidemiological surveillance is hampered by inconsistent reporting, antigenic heterogeneity of O. tsutsugamushi strains and limited laboratory capacity in resource-constrained settings. Empirical therapy with doxycycline or azithromycin remains the mainstay of management, yet diagnostic uncertainty and rising reports of azithromycin resistance in some regions underscore the need for improved point-of-care tests. Control measures focus on personal protective behaviour, vector habitat management and timely case detection. Despite decades of research, no licensed vaccine exists and gaps persist in understanding protective immunity, strain diversity and long-term sequelae. A coordinated global strategy coupling enhanced surveillance, standardised diagnostics and vaccine development is essential to reduce the burden of scrub typhus.

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Scrub Typhus Epidemiology and Clinical Management publication trend

The graph below shows the total number of articles in scrub typhus epidemiology and clinical management across all publications each year (not limited to Nature Index journals).

Technical terms

Orientia tsutsugamushi: Intracellular bacterium that causes scrub typhus.

Trombiculid mites: Larval mites (‘chiggers’) that serve as both reservoir and vector for O. tsutsugamushi.

Eschar: Necrotic skin lesion at mite bite site, often a diagnostic clue in scrub typhus.

Meningoencephalitis: Inflammation of both the meninges and brain parenchyma, a severe complication of infection.

Area under the curve (AUC): Measure of diagnostic or predictive model performance; higher values indicate better discrimination.

References

1. Construction and validation of a predictive model for meningoencephalitis in pediatric scrub typhus based on machine learning algorithms. Emerging Microbes & Infections (2025).
2. A scrub typhus vaccine presents a challenging unmet need. npj Vaccines (2023).
3. Brain transcriptomics reveal the activation of neuroinflammation pathways during acute Orientia tsutsugamushi infection in mice. Frontiers in Immunology (2023).
4. A Review of Scrub Typhus (Orientia tsutsugamushi and Related Organisms): Then, Now, and Tomorrow. Tropical Medicine and Infectious Disease (2018).
5. Scrub Typhus: No Longer Restricted to the Tsutsugamushi Triangle. Tropical Medicine and Infectious Disease (2018).