title: Evaluation of nested PCR for the diagnosis of scrub typhus among patients with acute pyrexia of unknown origin.
abstract: A nested PCR technique was performed to detect a specific 483 bp DNA fragment of Orientia tsutsugamushi, the aetiological agent of scrub typhus, in 53 blood samples from 36 patients with acute pyrexia of unknown origin in southern Thailand. The specific primers could amplify the specific DNA from all 10 prototype strains of O. tsutsugamushi and all nine seropositive patients and three seronegative patients, while no DNA amplification was obtained with DNAs from other rickettsiae or from healthy persons or from patients with murine typhus. The specific PCR product was detectable in the blood for as long as 22 days after the onset of disease in patients without specific treatment and 27 days after receiving a single dose of doxycycline. Thus, nested PCR may be more sensitive than the serological test for diagnosis of scrub typhus and prolonged persistence of O. tsutsugamushi DNA in patients' blood was demonstrated despite clinical recovery of the patients.
authors.affiliation: Department of Medical Science, National Institute of Health, Nonthaburi, Thailand.
authors.forename: Watcharee
authors.initials: W
authors.lastname: Saisongkorh
authors.forename: Mongkol
authors.initials: M
authors.lastname: Chenchittikul
authors.forename: Khachornsakdi
authors.initials: K
authors.lastname: Silpapojakul
mesh_terms: D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D000907:Antibodies, Bacterial / Q000097:blood; D002648:Child; D004269:DNA, Bacterial / Q000032:analysis; D004318:Doxycycline / Q000627:therapeutic use; D005260:Female; D005335:Fever of Unknown Origin / Q000209:etiology*; D005455:Fluorescent Antibody Technique; D006801:Humans; D008297:Male; D008875:Middle Aged; D012285:Orientia tsutsugamushi / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D016133:Polymerase Chain Reaction / Q000379:methods*; D012612:Scrub Typhus / Q000150:complications* / Q000175:diagnosis / Q000188:drug therapy; D012680:Sensitivity and Specificity; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents; D000907:Antibodies, Bacterial; D004269:DNA, Bacterial; D004318:Doxycycline