Tags

Type your tag names separated by a space and hit enter

Evaluation of loop-mediated isothermal amplification assay for detection of scrub typhus in patients with acute febrile illness presenting to a Tertiary Care Center in Puducherry, India.
J Lab Physicians 2019 Jan-Mar; 11(1):82-86JL

Abstract

PURPOSE

Scrub typhus an acute febrile illness has diverse clinical manifestations, which overlap with other febrile illnesses. Due to this reason, it is misdiagnosed, leading to inappropriate treatment, sometimes resulting in fatality. Thus, accurate diagnosis of scrub typhus is important for appropriate treatment. This study evaluated the loop-mediated isothermal amplification (LAMP) assay as a diagnostic test for scrub typhus among patients with fever.

MATERIALS AND METHODS

A total of 50 cases of acute febrile illness clinically resembling scrub typhus, with or without an eschar, or cases of pyrexia of unknown origin were included in the study. Blood samples collected from these cases were subjected to detection of IgM antibodies to Orientia tsutsugamushi by ELISA, conventional groEL polymerase chain reaction (PCR), and the LAMP assay.

RESULTS

Twelve cases had fever for less than a week, and two had fever for more than 3 weeks. IgM antibodies to O. tsutsugamushi were detected in 37 out of 50 samples (74%). LAMP assay was positive in 33 samples (66%). groEL gene-based PCR detected 35 (70%) samples as positive. Two samples negative by LAMP assay were positive by this PCR. Twenty samples collected from patients with dengue, typhoid, and malaria tested by the LAMP assay were negative, indicating its good specificity. LAMP assay and the conventional groEL-based PCR could detect 72.7% and 74.3% of the samples, respectively before the 10th day after onset of fever, whereas IgM ELISA could detect only 40.5% of the 37 samples.

CONCLUSION

This study suggests that LAMP assay could be a useful diagnostic test for detecting scrub typhus in the acute phase of the illness and a cheaper alternative to other molecular methods in resource poor settings.

Authors+Show Affiliations

Vector Control Research Centre, Puducherry, India.Regional Medical Research Centre, Belagavi, Karnataka, India.Department of Microbiology, Pondicherry Institute of Medical Sciences, Puducherry, India.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

30983808

Citation

Karthikeyan, Patricia Anitha, et al. "Evaluation of Loop-mediated Isothermal Amplification Assay for Detection of Scrub Typhus in Patients With Acute Febrile Illness Presenting to a Tertiary Care Center in Puducherry, India." Journal of Laboratory Physicians, vol. 11, no. 1, 2019, pp. 82-86.
Karthikeyan PA, Hoti SL, Kanungo R. Evaluation of loop-mediated isothermal amplification assay for detection of scrub typhus in patients with acute febrile illness presenting to a Tertiary Care Center in Puducherry, India. J Lab Physicians. 2019;11(1):82-86.
Karthikeyan, P. A., Hoti, S. L., & Kanungo, R. (2019). Evaluation of loop-mediated isothermal amplification assay for detection of scrub typhus in patients with acute febrile illness presenting to a Tertiary Care Center in Puducherry, India. Journal of Laboratory Physicians, 11(1), pp. 82-86. doi:10.4103/JLP.JLP_148_18.
Karthikeyan PA, Hoti SL, Kanungo R. Evaluation of Loop-mediated Isothermal Amplification Assay for Detection of Scrub Typhus in Patients With Acute Febrile Illness Presenting to a Tertiary Care Center in Puducherry, India. J Lab Physicians. 2019;11(1):82-86. PubMed PMID: 30983808.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Evaluation of loop-mediated isothermal amplification assay for detection of scrub typhus in patients with acute febrile illness presenting to a Tertiary Care Center in Puducherry, India. AU - Karthikeyan,Patricia Anitha, AU - Hoti,Sugeerappa Laxmanappa, AU - Kanungo,Reba, PY - 2019/4/16/entrez PY - 2019/4/16/pubmed PY - 2019/4/16/medline KW - Diagnosis KW - groEl polymerase chain reaction KW - loop-mediated isothermal amplification assay KW - scrub typhus SP - 82 EP - 86 JF - Journal of laboratory physicians JO - J Lab Physicians VL - 11 IS - 1 N2 - PURPOSE: Scrub typhus an acute febrile illness has diverse clinical manifestations, which overlap with other febrile illnesses. Due to this reason, it is misdiagnosed, leading to inappropriate treatment, sometimes resulting in fatality. Thus, accurate diagnosis of scrub typhus is important for appropriate treatment. This study evaluated the loop-mediated isothermal amplification (LAMP) assay as a diagnostic test for scrub typhus among patients with fever. MATERIALS AND METHODS: A total of 50 cases of acute febrile illness clinically resembling scrub typhus, with or without an eschar, or cases of pyrexia of unknown origin were included in the study. Blood samples collected from these cases were subjected to detection of IgM antibodies to Orientia tsutsugamushi by ELISA, conventional groEL polymerase chain reaction (PCR), and the LAMP assay. RESULTS: Twelve cases had fever for less than a week, and two had fever for more than 3 weeks. IgM antibodies to O. tsutsugamushi were detected in 37 out of 50 samples (74%). LAMP assay was positive in 33 samples (66%). groEL gene-based PCR detected 35 (70%) samples as positive. Two samples negative by LAMP assay were positive by this PCR. Twenty samples collected from patients with dengue, typhoid, and malaria tested by the LAMP assay were negative, indicating its good specificity. LAMP assay and the conventional groEL-based PCR could detect 72.7% and 74.3% of the samples, respectively before the 10th day after onset of fever, whereas IgM ELISA could detect only 40.5% of the 37 samples. CONCLUSION: This study suggests that LAMP assay could be a useful diagnostic test for detecting scrub typhus in the acute phase of the illness and a cheaper alternative to other molecular methods in resource poor settings. SN - 0974-2727 UR - https://www.unboundmedicine.com/medline/citation/30983808/Evaluation_of_loop_mediated_isothermal_amplification_assay_for_detection_of_scrub_typhus_in_patients_with_acute_febrile_illness_presenting_to_a_Tertiary_Care_Center_in_Puducherry_India_ L2 - http://www.jlponline.org/article.asp?issn=0974-2727;year=2019;volume=11;issue=1;spage=82;epage=86;aulast=Karthikeyan DB - PRIME DP - Unbound Medicine ER -