Volume 87, Issue 1
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645



We evaluated the diagnostic accuracy of two broadly reactive rapid immunochromatographic tests (ICTs) for detection of IgM and IgG against by using archived acute-phase serum samples from 102 patients with laboratory-confirmed scrub typhus, and from 62 archived serum samples from patients with other causes of fever as a negative control. These ICTs were constructed by using a mixture of recombinant proteins: 1) C1, a chimeric protein containing epitopes of the 56-kD antigen from Karp and TA763 strains; 2) Ktr56; and 3) Gmr56. Sensitivities of the ICTs for detection of IgM and IgG were 90.2% (95% confidence interval [CI] = 84.4–96.0%) and 86.3% (95% CI = 80.9–93.8%), respectively. Specificities were 85.5% (95% CI = 73.9–92.2%) and 96.8% (95% CI = 90.3–100%), respectively. Both assays were more sensitive and specific than the standard immune immunofluorescence assay for the early diagnosis of scrub typhus.


Article metrics loading...

Loading full text...

Full text loading...



  1. Watt G, Parola P, , 2003. Scrub typhus and tropical rickettsioses. Curr Opin Infect Dis 16: 429436.[Crossref]
  2. Silpapojakul K, , 1997. Scrub typhus in the Western Pacific region. Ann Acad Med Singapore 26: 794800.
  3. Thap LC, Supanaranond W, Treepresertsuk S, Kitvatanachai S, Chinprasatsak S, Phonrat B, , 2002. Septic shock secondary to scrub typhus: characteristics and complications. S E Asian J Trop Med Pub Health 33: 780786.
  4. Suttinont C, Losuwanaluk K, Niwatayakul K, Hoontrakul S, Intaranongpai W, Silpasakorn S, Suwancharoen D, Panlar P, Saisongkorh W, Rolain JM, Raoult D, Suputtamongkol Y, , 2006. Causes of acute undifferentiated febrile illness in rural Thailand: a prospective observational study. Ann Trop Med Hyg 100: 363370.[Crossref]
  5. Rolain JM, Jensenius M, Raoult D, , 2004. Rickettsial infections: a threat to travelers? Curr Opin Infect Dis 17: 433437.[Crossref]
  6. La Scola B, Raoult D, , 1997. Laboratory diagnosis of rickettsioses: current approaches to diagnosis of old and new rickettsial diseases. J Clin Microbiol 35: 27152727.
  7. Suputtamongkol Y, Niwattayakul K, Suttinont C, Losuwanaluk K, Limpaiboon R, Chierakul W, Wuthiekanun V, Triengrim S, Chenchittikul M, White NJ, , 2004. An open, randomized, controlled trial of penicillin, doxycycline, and cefotaxime for patients with severe leptospirosis. Clin Infect Dis 39: 14171424.[Crossref]
  8. Sonthayanon P, Chierakul W, Wuthiekanun V, Blacksell SD, Pimda K, Suputtamongkol Y, Pukrittayakamee S, White NJ, Day NP, Peacock SJ, , 2006. Rapid diagnosis of scrub typhus in rural Thailand using polymerase chain reaction. Am J Trop Med Hyg 75: 10991102.
  9. Wongprompitak P, Anukool W, Wongsawat E, Silpasakorn S, Dyong V, Buchy P, Morand S, Frutos R, Ekpo P, Suputtamongkol Y, , 2011. Broad-coverage molecular epidemiology of Orientia tsutsugamushi in Thailand. Infect Genet Evol 25: [Epub ahead of print].
  10. Bozeman FM, Elisberg BL, , 1963. Serological diagnosis of scrub typhus by indirect immunofluorescence. Proc Soc Exp Biol Med 112: 568573.[Crossref]
  11. Chao CC, Huber ES, Porter TB, Zhang Z, Ching WM, , 2011. Analysis of the cross-reactivity of various 56 kDa recombinant protein antigens with serum samples collected after Orientia tsutsugamushi infection by ELISA. Am J Trop Med 84: 967972.[Crossref]
  12. Yang Q, Ching WM, Jiang J, Lousteau L, Richards AL, , 2003. An improved method for the purification and refolding of r56-kDa proteins from Gilliam and Kato strains of Orientia tsutsugamushi . Ann N Y Acad Sci 990: 375385.[Crossref]
  13. Chaudhuri B, Raychaudhuri S, , 2001. Manufacturing High-Quality Gold Sol: Understanding Key Engineering Aspects of the Production of Colloidal Gold Can Optimize the Quality and Stability of Gold Labeling Components. IVT Technology. Available at: www.ivdtechnology.com.
  14. Suputtamongkol Y, Pongtavornpinyo W, Lubell Y, Suttinont C, Hoontrakul S, Phimda K, Losuwanaluk K, Suwancharoen D, Silpasakorn S, Chierakul W, Day N, , 2010. Strategies for diagnosis and treatment of suspected leptospirosis: a cost-benefit analysis. Plos Nleg Trop Med 4: e610.[Crossref]
  15. Bourgeois AL, Olson JG, Fang RCY, Huang J, Wang CL, Chow L, , 1982. Humoral and cellular responses in scrub typhus patients reflecting primary infection and reinfection with Rickettsia tsutsugamushi . Am J Trop Med 31: 532540.
  16. Kelly DJ, Fuerst PA, Ching WM, Richards AL, , 2009. Scrub typhus: the geographic distribution of phenotypic and genotypic variants of Orientia tsutsugamushi . Clin Infect Dis 48: S203S230.[Crossref]
  17. Shirai A, Robinson DM, Brown GW, Gan E, Huxsoll DL, , 1979. Antigenic analysis by direct immunofluorescence of 114 isolates of Rickettsia tsutsugamushi recovered from febrile patients in rural Malaysia. Jpn J Med Sci Biol 32: 337344.[Crossref]
  18. Tay ST, Rohani MY, Ho TM, Devi S, , 2002. Antigenic types of Orientia tsutsugamushi in Malaysia. Southeast Asian J Trop Med Public Health 33: 557564.

Data & Media loading...

  • Received : 15 Sep 2011
  • Accepted : 25 Mar 2012

Most Cited This Month

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error