Rickettsiosis in Southeast Asia: Summary for International Travellers during the COVID-19 Pandemic

Abstract

Rickettsiosis is an important cause of febrile illness among travellers visiting Southeast Asia (SEA). The true incidence of rickettsiosis is underestimated; however, murine typhus and scrub typhus are widely distributed across SEA. Among travellers visiting SEA, scrub typhus was mostly reported from Thailand, whereas murine typhus was frequently found in Indonesia. Although most cases are self-limited or present with mild symptoms, a few cases with severe clinical manifestations have been reported. Doxycycline remains the key treatment of rickettsiosis. Some travellers, such as backpackers, trekkers, or cave explorers, are at a higher risk for rickettsiosis than others. Therefore, in resource-limited conditions, empirical treatment should be considered in these travellers. The coronavirus disease 2019 (COVID-19) pandemic has contributed to difficulty in the diagnosis of rickettsiosis because of the clinical similarities between these diseases. In addition, physical distancing mandated by COVID-19 management guidelines limits accurate physical examination, resulting in misdiagnosis and delayed treatment of rickettsiosis. This review summarises the characteristics of murine typhus and scrub typhus, describes travel-associated rickettsiosis, and discusses the impact of the COVID-19 pandemic on rickettsiosis.

Keywords: COVID-19; Southeast Asia; coronavirus disease 2019; murine typhus; rickettsiosis; scrub typhus; travellers.

Figure 1

Eschar on the back of a patient with scrub typhus. Unidentified patient photo from Thundon Ngamprasertchai, MD.

Figure 2

Demonstration of reported scrub typhus and murine typhus cases in Southeast Asia. Figure by Mrs. Siwaporn Panphoowong (Adobe Illustrator).