Volume 70, Issue 4
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645


Two specific and sensitive polymerase chain reaction (PCR) assays were developed to detect and quantitate , the agent of scrub typhus, using a portion of the 47-kD outer membrane protein antigen/ high temperature requirement A gene as the target. A selected 47-kD protein gene primer pair amplified a 118-basepair fragment from all 26 strains of evaluated, but it did not produce amplicons when 17 and 18 less-related bacterial nucleic acid extracts were tested. Similar agent specificity for the real-time PCR assay, which used the same primers and a 31-basepair fluorescent probe, was demonstrated. This sensitive and quantitative assay determination of the content of nucleic acid used a plasmid containing the entire 47-kD gene from the Kato strain as a standard. Enumeration of the copies of DNA extracted from infected tissues from mice and monkeys following experimental infection with showed 27-5,552 copies/μL of mouse blood, 14,448-86,012 copies/μL of mouse liver/spleen homogenate, and 3-21 copies/μL of monkey blood.


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  1. Silpapojakul K, 1997. Scrub typhus in the western Pacific region. Ann Acad Med Singapore 26 : 794–800. [Google Scholar]
  2. Richards AL, Teik OC, Lockman JL, Rahardjo E, Wignall FS, 1997. Scrub typhus in an American living in Jakarta, Indonesia. Infect Dis Clin Pract 6 : 268–273. [Google Scholar]
  3. Yi KS, Chong Y, Covington SC, Donahue BJ, Rothen RL, Rodriguez J, Arthur JD, 1993. Scrub typhus in Korea: importance of early clinical diagnosis in this newly recognized endemic area. Mil Med 158 : 269–273. [Google Scholar]
  4. Smadel JE, Elisberg BL, 1965. Scrub typhus rickettsia. Horsfall FL, Tamm, I eds. Viral and Rickettsial Infections of Man. Fourth edition. Philadelphia: J.B. Lippincott, 1130–1143.
  5. Rosenberg R, 1997. Drug resistant scrub typhus: paradigm and paradox. Parasitol Today 13 : 131–132. [Google Scholar]
  6. Kawamura A, Tanaka H, 1988. Rickettsiosis in Japan. Jpn J Exp Med 58 : 169–184. [Google Scholar]
  7. Traub R, Wisseman C, 1974. Ecology of chigger-borne rickettsioses. J Med Entomol 3 : 237–303. [Google Scholar]
  8. Traub R, 1954. Advances in our knowledge of military medical importance of mites and fleas due to postwar experiences in the Pacific area. Recent Advances in Medicine and Surgery. Washington, DC: Army Medical Service Graduate School, 284–294.
  9. Strickman D, Tanskul P, Eamsila C, Kelly DJ, 1994. Prevalence of antibodies to rickettsiae in the human population of suburban Bangkok. Am J Trop Med Hyg 51 : 149–153. [Google Scholar]
  10. Tanskul P, Linthicum K, Watcharapichat P, Phulsuksombati D, Mungviriya S, Ratanatham S, Suwanabun N, Sattabongkot J, Watt G, 1998. A new ecology for scrub typhus associated with a focus of antibiotic resistance in rice farmers in Thailand. J Med Entomol 35 : 551–555. [Google Scholar]
  11. Brown GW, Robinson DM, Huxsoll DL, 1976. Scrub typhus: a common cause of illness in indigenous populations. Trans R Soc Trop Med Hyg 70 : 444–448. [Google Scholar]
  12. Tay ST, Kamalanathan M, Rohani MY, 2003. Detection of rickettsial antibodies using Weil-Felix (OXK and OX19) antigens and the indirect immunoperoxidase assay. Southeast Asia J Trop Med Public Health 34 : 171–174. [Google Scholar]
  13. 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 : 900–905. [Google Scholar]
  14. Yamamoto S, Minamishima Y, 1982. Serodiagnosis of tsutsugamushi fever (scrub typhus) by the indirect immunoperoxidase technique. J Clin Microbiol 15 : 1128–1132. [Google Scholar]
  15. Dasch GA, Halle S, Bourgeois AL, 1979. Sensitive microplate enzyme-linked immunosorbent assay for detection of antibodies against scrub typhus rickettsia, Rickettsia tsutsugamushi. J Clin Microbiol 9 : 38–48. [Google Scholar]
  16. Weddle JR, Chan TC, Thompson K, Paxton H, Kelly DJ, Dasch G, Strickman D, 1995. Effectiveness of a dot-blot immunoassay of anti-Rickettsia tsutsugamushi antibodies for serologic analysis of scrub typhus. Am J Trop Med Hyg 53 : 43–46. [Google Scholar]
  17. Kim IS, Seong SY, Woo SG, Choi MS, Chang WH, 1993. High-level expression of a 56-kilodalton protein gene (bor56) of Rickettsia tsutsugamushi Boryong and its application to enzyme-linked immunosorbent assays. J Clin Microbiol 31 : 598–605. [Google Scholar]
  18. Kim IS, Seong SY, Woo SG, Choi MS, Kang JS, Chang WH, 1993. Rapid diagnosis of scrub typhus by a passive hemagglutination assay using recombinant 56-kilodalton polypeptides. J Clin Microbiol 31 : 2057–2060. [Google Scholar]
  19. Ching WM, Wang H, Eamsila C, Kelly DJ, Dasch GA, 1998. Expression and refolding of truncated recombinant major outer membrane protein antigen (r56) of Orientia tsutsugamushi and its use in enzyme-linked immunosorbent assays. Clin Diagn Lab Immunol 5 : 519–526. [Google Scholar]
  20. 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 : 409–414. [Google Scholar]
  21. Wilkinson R, Rowland D, Ching W-M, 2003. Development of an improved rapid lateral flow assay for the detection of Orientia tsutsugamushi specific IgG/IgM antibodies. Ann N Y Acad Sci 990 : 386–390. [Google Scholar]
  22. Coleman RE, Sangkasuwan V, Suwanabun N, Ching W-M, Sattabongkot J, Eamsila C, Richards AL, Rowland D, Devine P, 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 : 497–503. [Google Scholar]
  23. Hechemy KE, Rikihisa Y, 2002. Immunoserology of the Rickettsiales, Bartonella, and Coxiella. Rose NR, Hamilton RG, Detrick B, eds. Manual of Clinical Laboratory Immunology. Sixth edition. Washington, DC: American Society for Microbiology Press, 528–541.
  24. Watt G, Olson JG, 2000. Scrub typhus. Strickland GT, ed. Hunter’s Tropical Medicine and Emerging Infectious Diseases. Eighth edition. Philadelphia, PA: W.B. Saunders Company, 443–445.
  25. Ridgway RL, Oaks SC Jr, LaBarre DD, 1986. Laboratory animal models for human scrub typhus. Lab Animal Sci 36 : 481–485. [Google Scholar]
  26. Shirai A, Saunders JP, Dohany AL, Huxsoll DL, Groves MG, 1982. Transmission of scrub typhus to human volunteers by laboratory-reared chiggers. Jpn J Med Sci Biol 35 : 9–16. [Google Scholar]
  27. Kelly DJ, Richards AL, Temenak J, Strickman D, Dasch GA, 2002. The past and present threat of rickettsial diseases to military medicine and international public health. Clin Infect Dis 34 : S145–S169. [Google Scholar]
  28. Furuya Y, Yoshida Y, Katayama T, Kawamori F, Yamamoto S, Ohashi N, Tamura A, Kawamura A, 1991. Specific amplification of Rickettsia tsutsugamushi DNA from clinical specimens by polymerase chain reaction. J Clin Microbiol 29 : 2628–2630. [Google Scholar]
  29. Murai K, Tachibana N, Okayama A, Shishime E, Tsuda K, Oshikawa T, 1992. Sensitivity of polymerase chain reaction assay for Rickettsia tsutsugamushi in patients’ blood samples. Microbiol Immunol 36 : 1145–1153. [Google Scholar]
  30. Horinouchi H, Murai K, Okayama A, Nagatomo Y, Tachibana N, Tsubouchi H, 1996. Genotypic identification of Rickettsia tsutsugamushi by restriction fragment length polymorphism analysis of DNA amplified by the polymerase chain reaction. Am J Trop Med Hyg 54 : 647–651. [Google Scholar]
  31. Kelly DJ, Dasch GA, Chan TC, Ho TM, 1994. Detection and characterization of Rickettsia tsutsugamushi (Rickettsiales: Rickettsiaceae) in infected Leptotromibidium (Leptroptrombidium) fletcheri chiggers (Acari: Trombiculidae) with the polymerase chain reaction. J Med Entomol 31 : 691–699. [Google Scholar]
  32. Ree H-I, Kim T-E, Lee I-Y, Jeon S-H, Hwang U-W, Chang W-H, 2001. Determination and geographic distribution of Orientia tsutsugamushi serotypes in Korea by nested polymerase chain reaction. Am J Trop Med Hyg 65 : 528–534. [Google Scholar]
  33. Ge H, Chuang Y-Y, Zhao S, Tong M, Tsai M-H, Temenak JJ, Richards AL, Ching W-M, 2004. Comparative genomics of Rickettsial prowazekii Madrid E and Breinl strains. J Bacteriol 186 : 556–565. [Google Scholar]
  34. Weisburg WG, Dobson ME, Samuel JE, Dasch GA, Mallavia LP, Baca O, Mandelco L, Sechrest JE, Weiss E, Woese CR, 1989. Phylogenetic diversity of the rickettsiae. J Bacteriol 171 : 4202–4206. [Google Scholar]
  35. Kelly DJ, Marana DP, Stover CK, Oaks EV, Carl M, 1990. Detection of Rickettsia tsutsugamushi by gene amplification using polymerase chain reaction techniques. Ann N Y Acad Sci 590 : 564–571. [Google Scholar]
  36. Dasch GA, Strickman D, Watt G, Eamsila C, 1996. Measuring genetic variability in Orientia tsutsugamushi by PCR/RFLP analysis: a new approach to questions about its epidemiology, evolution, and ecology. Kazar J ed. Rickettsiae and Rickettsial Diseases. Vth International Symposium. Bratislava, Slovakia: Slovak Academy of Sciences, 79–84.
  37. Dasch GA, Jackson LM, 1998. Genetic analysis of isolates of the spotted fever group of rickettsiae belonging to the R. conorii complex. Ann N Y Acad Sci 849 : 11–20. [Google Scholar]
  38. Eremeeva ME, Ching W-M, Wu Y, Silverman DJ, Dasch GA. Western blotting analysis of heat shock proteins of Rickettsiales and other eubacteria. FEMS Microbiol Lett 167 : 229–237. [Google Scholar]
  39. Chan TC, Jiang J, Temenak JJ, Richards AL, 2003. Development of a rapid method for determining the infectious dose (ID)50 of Orientia tsutsugamushi in a scrub typhus mouse model for the evaluation of vaccine candidates. Vaccine 21 : 4550–4554. [Google Scholar]
  40. Boostrom A, Beier MS, Macaluso JA, Macaluso KR, Sprenger D, Hayes J, Radulovic S, Azad AF, 2002. Geographic association of Rickettsia felis-infected opossums with human murine typhus, Texas. Emerg Infect Dis 8 : 549–554. [Google Scholar]
  41. Davis LG, Dibner MD, Battey JF, 1986. Optical density analytical measurements. Basic Methods in Molecular Biology. New York: Elsevier Science Publishing Co. Inc., 327–328.
  42. Smadel JE, Ley HL Jr, Diercks FH, Traub R, 1950. Immunity in scrub typhus: resistance to induced reinfection. Arch Pathol 50 : 847–861. [Google Scholar]
  43. Kim J-H, Hahn M-J, 2000. Cloning and sequencing of the gene encoding the candidate HtrA of Rickettsia typhi. Microbial Immunol 44 : 275–278. [Google Scholar]
  44. Clausen T, Southan C, Ehrmann M, 2002. The HtrA family of proteases: implications for protein composition and cell fate. Mol Cell 10 : 443–455. [Google Scholar]

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  • Received : 24 Sep 2003
  • Accepted : 14 Dec 2003

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