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.

A Use of 56-kDa Recombinant Protein of Orientia tsutsugamushi Karp Serotype in Serodiagnosis of Scrub Typhus by Enzyme-Linked Immunosorbent Assay in Thais

“…A high disease prevalence is associated with agricultural workers and people living in rural and mountainous areas [ 11 ]. Clinical presentations of scrub typhus in humans include fever, myalgia, rash, lymphadenopathy, and conjunctival injection [ 12 ]. In approximately 50% of patients, an eschar, which represents a site of a chigger bite, can be seen.…”

“…Generally, diagnosis of scrub typhus is based on the clinical presentation and a patient’s history, with the presence of an eschar as a useful diagnostic clue. In the absence of an eschar, delayed diagnosis, complications, and high mortality may occur since the general manifestations of scrub typhus can resemble those in other febrile diseases such as leptospirosis, typhoid, murine typhus, malaria, dengue, and viral hemorrhagic fevers [ 4 , 12 , 13 ]. In cases with complications, the condition can involve multiple organ systems, resulting in pneumonitis, acute respiratory distress syndrome, acute kidney injury, myocarditis, meningoencephalitis, and hepatitis [ 4 ].…”

Febrile Rash: An Early Diagnostic Clue to Infectious Illness in Travelers Returning from Thailand

“…It is important to highlight that the symptoms of dengue infection may share similarities with those of other prevalent Flaviviruses viruses in Southeast Asia, such as Zika virus, Japanese encephalitis virus, and even Alphaviuses like chikungunya virus [6][7][8][9]. In addition to malaria, other arthropod-borne rickettsioses, including murine typhus, scrub typhus, or Thai tick typhus, may present with overlapping symptoms [10][11][12][13]. Therefore, it is important to consider these diverse infectious agents with respect to the extent of exposure when assessing potential cases returning from Thailand.…”