title: Scrub typhus in South India: clinical and laboratory manifestations, genetic variability, and outcome.
abstract: OBJECTIVE
  This study sought to document the clinical and laboratory manifestations, genetic variability, and outcomes of scrub typhus, an often severe infection caused by Orientia tsutsugamushi, in South India.
  
  
  METHODS
  Patients admitted to a large teaching hospital with IgM ELISA-confirmed scrub typhus were evaluated. Clinical examination with a thorough search for an eschar, laboratory testing, chest X-ray, and outcome were documented and analyzed. Additionally, a 410-bp region of the 56-kDa type-specific antigen gene of O. tsutsugamushi was sequenced and compared with isolates from other regions of Asia.
  
  
  RESULTS
  Most of the 154 patients evaluated presented with fever and non-specific symptoms. An eschar was found in 86 (55%) patients. Mild hepatic involvement was seen in most, with other organ involvement including respiratory, cardiovascular, and renal. Multi-organ dysfunction was noted in 59 (38.3%), and the fatality rate was 7.8%. Hypotension requiring vasoactive agents was found to be an independent predictor of mortality (p<0.001). The phylogeny of 26 samples showed 17 (65%) clustering with the Kato-like group and eight (31%) with the Karp-like group.
  
  
  CONCLUSIONS
  The presentation of scrub typhus can be variable, often non-specific, but with potentially severe multi-organ dysfunction. Prompt recognition is key to specific treatment and good outcomes. Further study of the circulating strains is essential for the development of a successful vaccine and sensitive point-of-care testing.
authors.affiliation: Medicine Unit I and Infectious Diseases, Christian Medical College, Vellore, Tamil Nadu, India. Electronic address: georgemvarghese@hotmail.com.
authors.forename: George M
authors.initials: GM
authors.lastname: Varghese
authors.forename: Jeshina
authors.initials: J
authors.lastname: Janardhanan
authors.forename: Paul
authors.initials: P
authors.lastname: Trowbridge
authors.forename: John V
authors.initials: JV
authors.lastname: Peter
authors.forename: John A J
authors.initials: JA
authors.lastname: Prakash
authors.forename: Sowmya
authors.initials: S
authors.lastname: Sathyendra
authors.forename: Kurien
authors.initials: K
authors.lastname: Thomas
authors.forename: Thambu S
authors.initials: TS
authors.lastname: David
authors.forename: M L
authors.initials: ML
authors.lastname: Kavitha
authors.forename: Ooriapadickal C
authors.initials: OC
authors.lastname: Abraham
authors.forename: Dilip
authors.initials: D
authors.lastname: Mathai
mesh_terms: D000328:Adult; D000942:Antigens, Bacterial / Q000235:genetics; D005260:Female; D014644:Genetic Variation; D006801:Humans; D007194:India / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D058889:Molecular Typing; D012285:Orientia tsutsugamushi / Q000235:genetics*; D017063:Outcome Assessment, Health Care; D011379:Prognosis; D012612:Scrub Typhus / Q000175:diagnosis* / Q000453:epidemiology*
chemical_list: D000942:Antigens, Bacterial
keywords: Clinical manifestations; Genetic variability; Orientia tsutsugamushi; Outcome; Scrub typhus