Scrub typhus in South India: clinical and laboratory manifestations, genetic variability, and outcome

• Published in: International journal of infectious diseases Vol. 17; no. 11; pp. e981 - e987
• Main Authors: Varghese, George M, Janardhanan, Jeshina, Trowbridge, Paul, Peter, John V, Prakash, John A.J, Sathyendra, Sowmya, Thomas, Kurien, David, Thambu S, Kavitha, M.L, Abraham, Ooriapadickal C, Mathai, Dilip
• Format: Journal Article
• Language: English
• Published: Canada Elsevier Ltd 01-11-2013
• Subjects: Adult; Antigens, Bacterial - genetics; Clinical manifestations; Female; Genetic variability; Genetic Variation; Humans; India - epidemiology; Infectious Disease; Male; Middle Aged; Molecular Sequence Data; Molecular Typing; Orientia tsutsugamushi; Orientia tsutsugamushi - genetics; Outcome; Outcome Assessment (Health Care); Prognosis; Pulmonary/Respiratory; Scrub typhus; Scrub Typhus - diagnosis; Scrub Typhus - epidemiology; India; Clinical manifestations; Scrub typhus; Genetic variability; Orientia tsutsugamushi; Outcome
• ISSN: 1201-9712; 1878-3511
• DOI: 10.1016/j.ijid.2013.05.017

Summary Objectives 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.