Detection of Immunoglobulin M and Immunoglobulin G Antibodies Against Orientia tsutsugamushi for Scrub Typhus Diagnosis and Serosurvey in Endemic Regions

ABSTRACT To differentiate scrub typhus from other acute febrile diseases, a rapid and reliable serological diagnosis is important. We developed an immunoglobulin M (IgM) capture enzyme-linked immunosorbent assay (ELISA) for diagnosis of recent Orientia tsutsugamushi infections in humans. The 56-kDa major outer membrane protein of O. tsutsugamushi is well known as the most immunodominant antigen in scrub typhus. The test is based on the use of the biotinylated recombinant 56-kDa protein of O. tsutsugamushi Boryong, Bor56, which was expressed as a fusion protein with a maltose-binding protein in Escherichia coli. In the test, the serum IgM antibodies were captured by anti-human IgM antibodies coated onto a microtiter plate. The captured IgM antibodies were revealed through sequential addition of biotinylated Bor56 antigen and peroxidase-conjugated streptavidin to the plate. The IgM capture ELISA was compared with the immunofluorescence antibody assay (IFA) by testing 176 serum samples from patients with diagnosed cases of rickettsial disease and patients with other acute febrile diseases. Of the 81 IgG IFA-positive samples, 78 tested positive (sensitivity, 96.3%) and all 31 IgM IFA-positive samples tested positive (sensitivity, 100%) by the IgM capture ELISA. The specificity of the IgM capture ELISA was 99%, and 1 of the 95 IFA-negative samples was positive in the assay. These results strongly suggest that IgM capture ELISA using the recombinant Bor56 antigen is a reliable and detailed method for the detection of early O. tsutsugamushi infection.

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Accuracy of AccessBio Immunoglobulin M and Total Antibody Rapid Immunochromatographic Assays for the Diagnosis of Acute Scrub Typhus Infection

Clinical and Vaccine Immunology ◽

10.1128/cvi.00448-08 ◽

2009 ◽

Vol 17 (2) ◽

pp. 263-266 ◽

Cited By ~ 21

Author(s):

Stuart D. Blacksell ◽

Kemajittra Jenjaroen ◽

Rattanaphone Phetsouvanh ◽

Vanaporn Wuthiekanun ◽

Nicholas P. J. Day ◽

...

Keyword(s):

Confidence Interval ◽

Scrub Typhus ◽

Immunoglobulin M ◽

Immunochromatographic Test ◽

Orientia Tsutsugamushi ◽

Archived Samples ◽

Diagnostic Capacity

ABSTRACT Using archived samples, we assessed the diagnostic capacity of a rapid immunochromatographic test (ICT) for the detection of Orientia tsutsugamushi IgM and total antibodies to aid with the diagnosis of acute scrub typhus infection in febrile patients in Laos. The sensitivity and the specificity of the ICT for the detection of IgM were 96.8% (121/125 samples; 95% confidence interval [CI], 92.1 to 99.1%) and 93.3% (98/105 samples; 95% CI, 86.7 to 97.3%), respectively. For the detection of total antibodies, the sensitivity was 97.6% (122/125 samples; 95% CI, 93.1 to 99.5%), but the specificity was much lower, at 71.4% (75/105 samples; 95% CI, 61.8 to 79.8%).

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Evaluation of Combined Rapid Immunoglobulin M and Immunoglobulin G Lateral Flow Assays for the Diagnosis of Leptospirosis, Scrub Typhus, and Hantavirus Infection

Siriraj Medical Journal ◽

10.33192/smj.2020.34 ◽

2020 ◽

Vol 72 (3) ◽

pp. 253-258

Author(s):

Yupin Suputtamongkol

Keyword(s):

Immunoglobulin G ◽

Scrub Typhus ◽

Lateral Flow ◽

Immunoglobulin M ◽

Hantavirus Infection ◽

Lateral Flow Assays

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Scrub typhus (Orientia tsutsugamushi), A rapidly spreading epidemic in Chennai - A standalone lab experience

International Journal of Bioassays ◽

10.21746/ijbio.2016.09.0021 ◽

2016 ◽

Vol 5 (09) ◽

pp. 4896

Author(s):

Sripriya C.S.* ◽

Shanthi B. ◽

Arockia Doss S. ◽

Antonie Raj I. ◽

Mohana Priya

Keyword(s):

Scrub Typhus ◽

Clinical Symptoms ◽

Clinical Manifestations ◽

Febrile Illness ◽

Orientia Tsutsugamushi ◽

The Past ◽

Igm Elisa ◽

The Mean ◽

Specific Symptoms ◽

Symptoms And Signs

Scrub typhus (Orientia tsutsugamushi), is a strict intracellular bacterium which is reported to be a recent threat to parts of southern India. There is re-emergence of scrub typhus during the past few years in Chennai. Scrub typhus is an acute febrile illness which generally causes non-specific symptoms and signs. The clinical manifestations of this disease range from sub-clinical disease to organ failure to fatal disease. This study documents our laboratory experience in diagnosis of scrub typhus in patients with fever and suspected clinical symptoms of scrub typhus infection for a period of two years from April 2014 to April 2016 using immunochromatography and IgM ELISA methods. The study was conducted on 648 patients out of whom 188 patients were found to be positive for scrub typhus. Results also showed that pediatric (0 -12 years) and young adults (20 – 39 years) were more exposed to scrub typhus infection and female patients were more infected compared to male. The study also showed that the rate of infection was higher between September to February which also suggested that the infection rate is proportional to the climatic condition. Statistical analysis showed that the mean age of the patients in this study was 37.6, standard deviation was 18.97, CV % was 50.45.

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Immunoglobulin M and Immunoglobulin G Subclass Distribution of Anti-galactose-Alpha-1,3-Galactose and Anti-N-Glycolylneuraminic Acid Antibodies in Healthy Korean Adults

Transplantation Proceedings ◽

10.1016/j.transproceed.2021.01.011 ◽

2021 ◽

Author(s):

Eun Jin Lee ◽

Haneulnari Lee ◽

Eun Mi Park ◽

Hee Jung Kang ◽

Sang Joon Kim ◽

...

Keyword(s):

Immunoglobulin G ◽

Immunoglobulin M ◽

Korean Adults ◽

Immunoglobulin G Subclass

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Scrub Typhus and Molecular Characterization of Orientia tsutsugamushi from Central Nepal

Pathogens ◽

10.3390/pathogens10040422 ◽

2021 ◽

Vol 10 (4) ◽

pp. 422

Author(s):

Rajendra Gautam ◽

Keshab Parajuli ◽

Mythili Tadepalli ◽

Stephen Graves ◽

John Stenos ◽

...

Keyword(s):

Genetic Diversity ◽

Scrub Typhus ◽

Febrile Illness ◽

Acute Febrile Illness ◽

Limited Information ◽

Orientia Tsutsugamushi ◽

Health Measures ◽

Central Nepal ◽

Vector Borne

Scrub typhus is a vector-borne, acute febrile illness caused by Orientia tsutsugamushi. Scrub typhus continues to be an important but neglected tropical disease in Nepal. Information on this pathogen in Nepal is limited to serological surveys with little information available on molecular methods to detect O. tsutsugamushi. Limited information exists on the genetic diversity of this pathogen. A total of 282 blood samples were obtained from patients with suspected scrub typhus from central Nepal and 84 (30%) were positive for O. tsutsugamushi by 16S rRNA qPCR. Positive samples were further subjected to 56 kDa and 47 kDa molecular typing and molecularly compared to other O. tsutsugamushi strains. Phylogenetic analysis revealed that Nepalese O. tsutsugamushi strains largely cluster together and cluster away from other O. tsutsugamushi strains from Asia and elsewhere. One exception was the sample of Nepal_1, with its partial 56 kDa sequence clustering more closely with non-Nepalese O. tsutsugamushi 56 kDa sequences, potentially indicating that homologous recombination may influence the genetic diversity of strains in this region. Knowledge on the circulating strains in Nepal is important to the development of diagnostic tests and vaccines to support public health measures to control scrub typhus in this country.

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1495Resistance of Fluoroquinolone in Orientia tsutsugamushi Due to gyrA Mutation in Scrub typhus

Open Forum Infectious Diseases ◽

10.1093/ofid/ofu052.1041 ◽

2014 ◽

Vol 1 (suppl_1) ◽

pp. S395-S395

Author(s):

Soo Kyung CHO ◽

Kyung Hwa Park ◽

Su Mi Choi ◽

Sook in Jung ◽

Hee-Chang Jang ◽

...

Keyword(s):

Scrub Typhus ◽

Orientia Tsutsugamushi ◽

Gyra Mutation

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Diagnostic Accuracy of the InBios Scrub Typhus Detect™ ELISA for the Detection of IgM Antibodies in Chittagong, Bangladesh

Tropical Medicine and Infectious Disease ◽

10.3390/tropicalmed3030095 ◽

2018 ◽

Vol 3 (3) ◽

pp. 95 ◽

Cited By ~ 7

Author(s):

Stuart Blacksell ◽

Hugh Kingston ◽

Ampai Tanganuchitcharnchai ◽

Meghna Phanichkrivalkosil ◽

Mosharraf Hossain ◽

...

Keyword(s):

General Population ◽

Diagnostic Accuracy ◽

Diagnostic Tests ◽

Scrub Typhus ◽

Febrile Illness ◽

High Sensitivity ◽

Immunofluorescence Assay ◽

Immunoglobulin M ◽

Regional Assessment ◽

Igm Elisa

Here we estimated the accuracy of the InBios Scrub Typhus Detect™ immunoglobulin M (IgM) ELISA to determine the optimal optical density (OD) cut-off values for the diagnosis of scrub typhus. Patients with undifferentiated febrile illness from Chittagong, Bangladesh, provided samples for reference testing using (i) qPCR using the Orientia spp. 47-kDa htra gene, (ii) IFA ≥1:3200 on admission, (iii) immunofluorescence assay (IFA) ≥1:3200 on admission or 4-fold rise to ≥3200, and (iv) combination of PCR and IFA positivity. For sero-epidemiological purposes (ELISA vs. IFA ≥1:3200 on admission or 4-fold rise to ≥3200), the OD cut-off for admission samples was ≥1.25, resulting in a sensitivity (Sn) of 91.5 (95% confidence interval (95% CI: 96.8–82.5) and a specificity (Sp) of 92.4 (95% CI: 95.0–89.0), while for convalescent samples the OD cut-off was ≥1.50 with Sn of 66.0 (95% CI: 78.5–51.7) and Sp of 96.0 (95% CI: 98.3–92.3). Comparisons against comparator reference tests (ELISA vs. all tests including PCR) indicated the most appropriate cut-off OD to be within the range of 0.75–1.25. For admission samples, the best Sn/Sp compromise was at 1.25 OD (Sn 91.5%, Sp 92.4%) and for convalescent samples at 0.75 OD (Sn 69.8%, Sp 89.5%). A relatively high (stringent) diagnostic cut-off value provides increased diagnostic accuracy with high sensitivity and specificity in the majority of cases, while lowering the cut-off runs the risk of false positivity. This study underlines the need for regional assessment of new diagnostic tests according to the level of endemicity of the disease given the high levels of residual or cross-reacting antibodies in the general population.

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