title: Rickettsioses in the central hills of Sri Lanka: serological evidence of increasing burden of spotted fever group.
abstract: OBJECTIVE
  To study the epidemiology, clinical features, and changing pattern of rickettsial infections on the western slopes of the hilly Central Province of Sri Lanka over 6 years.
  
  
  METHODS
  All patients with rickettsial infections who presented to the Teaching Hospital, Peradeniya were studied prospectively from January 2002 to December 2007. An immunofluorescent antibody assay (IFA) was used to confirm the diagnosis.
  
  
  RESULTS
  Of the 371 clinical cases of rickettsial infection, 122 underwent IFA to confirm the diagnosis. Species-specific IgG antibodies were positive in 105/122 (86.1%) cases: 43/105 (40.9%) to Rickettsia conorii and 6/105 (5.7%) to Orientia tsutsugamushi, with mixed antibody reactivity to more than one antigen in 56/105 (53.3%) cases, including Rickettsia typhi in 27/105 (25.7%). Among those with mixed IgG reactivity, IgM assays were used to detect pathogens responsible for acute infections. Finally, a total of 55 spotted fever group (SFG) infections, seven scrub typhus infections, and one case of murine typhus were identified. Of the 105 positive cases, 53 (50.5%) were male and 52 (49.5%) were female, and the mean age was 40 years (range 11-83 years). In the SFG patients, 13/55 (24%) had severe vasculitis with fern leaf type skin necrosis and 17/55 (31%) had arthritis. Three patients (5%) had an altered level of consciousness. A patient with scrub typhus had transient deafness. None of the 105 patients had an eschar.
  
  
  CONCLUSIONS
  It appears that SFG rickettsioses are on the rise in the hilly Central Province of Sri Lanka, whilst murine typhus and scrub typhus are present at a lower rate.
authors.affiliation: Department of Medicine, Faculty of Medicine, University of Peradeniya, Kandy, Sri Lanka.
authors.forename: S A M
authors.initials: SA
authors.lastname: Kularatne
authors.forename: R P V J
authors.initials: RP
authors.lastname: Rajapakse
authors.forename: W M R S
authors.initials: WM
authors.lastname: Wickramasinghe
authors.forename: D M
authors.initials: DM
authors.lastname: Nanayakkara
authors.forename: S S
authors.initials: SS
authors.lastname: Budagoda
authors.forename: K G A D
authors.initials: KG
authors.lastname: Weerakoon
authors.forename: J S
authors.initials: JS
authors.lastname: Edirisinghe
authors.forename: R
authors.initials: R
authors.lastname: Premaratna
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000907:Antibodies, Bacterial / Q000276:immunology; D001907:Boutonneuse Fever / Q000175:diagnosis / Q000453:epidemiology / Q000276:immunology; D002648:Child; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D007075:Immunoglobulin M / Q000276:immunology; D008297:Male; D008875:Middle Aged; D012285:Orientia tsutsugamushi; D015995:Prevalence; D020114:Rickettsia conorii; D012286:Rickettsia typhi; D012287:Rickettsiaceae / Q000145:classification*; D012288:Rickettsiaceae Infections / Q000175:diagnosis / Q000453:epidemiology* / Q000276:immunology; D012612:Scrub Typhus / Q000175:diagnosis / Q000453:epidemiology / Q000276:immunology; D012621:Seasons; D012703:Serotyping; D013188:Sri Lanka / Q000453:epidemiology; D014437:Typhus, Endemic Flea-Borne / Q000175:diagnosis / Q000453:epidemiology / Q000276:immunology; D055815:Young Adult
chemical_list: D000907:Antibodies, Bacterial; D007074:Immunoglobulin G; D007075:Immunoglobulin M
keywords: Orientia tsutsugamushi; Rickettsia typhi; Rickettsial infections; Spotted fever group rickettsiae; Sri Lanka; Vasculitis