Volume 83, Issue 2
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645



We studied the diagnostic accuracy of a rapid immunochromatographic test (ICT) for detection of IgM against scrub typhus (ST ICT) and an immunoblot test for the detection of IgM against murine typhus (MT IBT) by using admission serum samples from 1,030 febrile patients in Laos. Sensitivity and specificity for the ST ICT determined by using the diagnostic criteria of a four-fold increase in IgM against between paired samples were 23.8% (95% confidence interval [CI] = 15.9–33.3%) and 86.2% (95% CI = 84.1–88.6%), respectively. Sensitivity and specificity for the ST ICT determined by using an admission IgM titer ≥ 1:400 were 39.1% (95% CI = 34.1–44.2%) and 99.5% (95% CI = 98.7–99.9%), respectively. Sensitivity and specificity for the MT IBT determined by using the criteria of a four-fold increase in IgM against between paired serum samples were 61.2% (95% CI = 53.7–68.3%) and 86.5% (95% CI = 84.1–88.8%), respectively. Sensitivity and specificity for the MT IBT determined by using an admission IgM titer ≥ 1:400 were 54.6% (95% CI = 49.1–60.0%) and 94.1% (95% CI = 92.0–95.7%), respectively. Both assays had relatively good specificity but low sensitivity and thus have limited utility for admission diagnosis.


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  1. Kamarasu K, Malathi M, Rajagopal V, Subramani K, Jagadeeshramasamy D, Mathai E, , 2007. Serological evidence for wide distribution of spotted fevers and typhus fever in Tamil Nadu. Indian J Med Res 126: 128130. [Google Scholar]
  2. Phongmany S, Rolain JM, Phetsouvanh R, Blacksell SD, Soukkhaseum V, Rasachack B, Phiasakha K, Soukkhaseum S, Frichithavong K, Chu V, Keolouangkhot V, Martinez-Aussel B, Chang K, Darasavath C, Rattanavong O, Sisouphone S, Mayxay M, Vidamaly S, Parola P, Thammavong C, Heuangvongsy M, Syhavong B, Raoult D, White NJ, Newton PN, , 2006. Rickettsial infections and fever, Vientiane, Laos. Emerg Infect Dis 12: 256262.[Crossref] [Google Scholar]
  3. Silpapojakul K, Pradutkanchana J, Pradutkanchana S, Kelly DJ, , 1995. Rapid, simple serodiagnosis of murine typhus. Trans R Soc Trop Med Hyg 89: 625628.[Crossref] [Google Scholar]
  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: results of a prospective observational study. Ann Trop Med Parasitol 100: 363370.[Crossref] [Google Scholar]
  5. Robinson DM, Brown G, Gan E, Huxsoll DL, , 1976. Adaptation of a microimmunofluorescence test to the study of human Rickettsia tsutsugamushi antibody. Am J Trop Med Hyg 25: 900905. [Google Scholar]
  6. Tay ST, Kamalanathan M, Rohani MY, , 2003. Antibody prevalence of Orientia tsutsugamushi, Rickettsia typhi and TT118 spotted fever group rickettsiae among Malaysian blood donors and febrile patients in the urban areas. Southeast Asian J Trop Med Public Health 34: 165170. [Google Scholar]
  7. Coleman RE, Sangkasuwan V, Suwanabun N, Eamsila C, Mungviriya S, Devine P, Richards AL, Rowland D, Ching WM, Sattabongkot J, Lerdthusnee K, , 2002. Comparative evaluation of selected diagnostic assays for the detection of IgG and IgM antibody to Orientia tsutsugamushi in Thailand. Am J Trop Med Hyg 67: 497503. [Google Scholar]
  8. Day NP, Newton PN, Cohen J, Powderly W, , 2010. Scrub Typhus and Other Tropical Rickettsioses. , eds. Infectious Diseases. London: Mosby, in press. [Google Scholar]
  9. Ching WM, Rowland D, Zhang Z, Bourgeois AL, Kelly D, Dasch GA, Devine PL, , 2001. Early diagnosis of scrub typhus with a rapid flow assay using recombinant major outer membrane protein antigen (r56) of Orientia tsutsugamushi . Clin Diagn Lab Immunol 8: 409414. [Google Scholar]
  10. Watt G, Jongsakul K, Ruangvirayuth R, Kantipong P, Silpapojakul K, , 2005. Short report: prospective evaluation of a multi-test strip for the diagnoses of scrub and murine typhus, leptospirosis, dengue fever, and Salmonella typhi infection. Am J Trop Med Hyg 72: 1012. [Google Scholar]
  11. Kelly DJ, Chan CT, Paxton H, Thompson K, Howard R, Dasch GA, , 1995. Comparative evaluation of a commercial enzyme immunoassay for the detection of human antibody to Rickettsia typhi . Clin Diagn Lab Immunol 2: 356360. [Google Scholar]
  12. Saunders JP, Brown GW, Shirai A, Huxsoll DL, , 1980. The longevity of antibody to Rickettsia tsutsugamushi in patients with confirmed scrub typhus. Trans R Soc Trop Med Hyg 74: 253257.[Crossref] [Google Scholar]
  13. Blacksell SD, Bryant NJ, Paris DH, Doust JA, Sakoda Y, Day NP, , 2007. Scrub typhus serologic testing with the indirect immunofluorescence method as a diagnostic gold standard: a lack of consensus leads to a lot of confusion. Clin Infect Dis 44: 391401.[Crossref] [Google Scholar]
  14. Parola P, Blacksell SD, Phetsouvanh R, Phongmany S, Rolain JM, Day NP, Newton PN, Raoult D, , 2008. Genotyping of Orientia tsutsugamushi from humans with scrub typhus, Laos. Emerg Infect Dis 14: 14831485.[Crossref] [Google Scholar]

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  • Received : 09 Sep 2009
  • Accepted : 18 Mar 2010
  • Published online : 05 Aug 2010

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