Emerging scrub typhus infection in the northern region of Sri Lanka

Abstract

BackgroundThere is an increasing trend in rickettsioses or typhus fevers in the island of Sri Lanka. The seroepidemiological mapping previously published did not include the northern region of the island. This study was conducted to demonstrate the presence of scrub typhus (ST) and to characterise the clinical presentation of ST in this region.FindingsSerum samples from patients (n = 64) with clinical symptoms suspected of typhus fever following exclusion of other common febrile illnesses commonly seen in the northern region of Sri Lanka were selected and screened for ST using specific IgM and IgG ELISA (ImBios, USA). ST was confirmed by serology in 54 patients, with typical eschar being found in 49 of cases positive for ST. Fever was the sole presenting complaint of these patients with the duration of febrile illness varying from 2–14 days. Of these patients 44.4% had regional lymphadenopathy, 18.5% hepatomegaly, 12.9% pneumonitis and 9.3% splenomegaly. None of the patients had a rash.ConclusionsThis study confirms the presence of high numbers of patients with ST in northern Sri Lanka. It was found that 84.4% of the patients presenting with clinical features of rickettsioses (54 of the 64) were seropositive for ST with a significant majority having a typical eschar. This data provided will enable clinicians to be vigilant of ST in this region and provide appropriate therapy and also facilitate planning for preventive measures aimed at reducing the burden of ST.

Revisiting clinico-epidemiological pattern of human rickettsial infections in the central region of Sri Lanka: a hospital based descriptive study

“…Rickettsial infections have re-emerged in Sri Lanka with predominance of spotted fever group (SFG) in the central hills [ 1 – 8 ]. Even though, clinical picture of the infection is typical in many situations, variations have been reported [ 1 , 2 , 4 ].…”

Rickettsioses in Sri Lanka – A mini review

“…18 The Northern Province has a predominance of scrub typhus. 24 However, an outbreak attributed to spotted fever, diagnosed by sero-positivity to Rickettisa conorii using IFA has been reported from army personnel within the Kilinochchi area from October to December 2012. 25 Premaratne et al reported that while scrub typhus was the predominant rickettsioses found among army personnel deployed in the Northern Province presenting with an acute febrile illness, the majority of apparently healthy army personnel had serological evidence of exposure to spotted fever.…”

“…21,34 Eschar is rarely associated with spotted fever. 18,21,24 However, in the outbreak of rickettsioses in the Kilinochchi area mentioned above, a considerable proportion of patients with serological evidence of spotted fever had demonstrated an eschar like lesion, particularly in the eye. 25 The rash in spotted fever is typically a macular papular rash.…”

Epidemiological Characteristics and Spatiotemporal Patterns of Scrub Typhus in Jiangxi Province, China, 2006-2018

“…It is estimated that one million cases of ST were found each year within this region, and at least one billion people are at risk of becoming infected 12,13 . Moreover, the incidence in all known endemic regions has begun to rise over the last decade [14][15][16][17] . Recent evidence from China indicated that ST has expanded to all the provinces across both rural and urban areas, and the incidence of ST has increased in an unprecedented manner, in both historically endemic areas and in new areas not previously identi ed as having cases 18 .…”