Assessment of two immunoassays for detection of IgM antibodies to scrub typhus using a serum panel

Elangovan, Divyaa; Perumalla, Susmitha Karunasree; Rose, Winsley; Verghese, Valsan Philip; Gowri, Mahasampath; Prakash, John Antony Jude

doi:10.1101/667410

Cited by 2 publications

(3 citation statements)

References 26 publications

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“…Almost always, the serological diagnosis is performed using the acute specimen. Therefore, determining the cut off value (clinically significant value) becomes important in each geographical areas as re-infections are quite common (57,76). The clinically significant value or titre can be robustly detected by testing known positive samples, samples from healthy individuals, and from individuals with diseases which have clinical features (especially eschar negative) similar to scrub typhus.…”

Section: Antibody Detection (Serological Assays)mentioning

confidence: 99%

“…The clinically significant value or titre can be robustly detected by testing known positive samples, samples from healthy individuals, and from individuals with diseases which have clinical features (especially eschar negative) similar to scrub typhus. The interested reader is referred to extensive reviews on this for further guidance (57,70,76).…”

Section: Antibody Detection (Serological Assays)mentioning

confidence: 99%

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Scrub typhus diagnostics: An overview

Bora²,

Perumalla

et al. 2023

Preprint

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Scrub typhus caused by Orientia tsutsugamushi is a vector-borne, zoonotic disease which is common in the tsutsugamushi triangle. Scrub typhus causes AUFI in patients with non-specific clinical features and is difficult to diagnose when the highly characteristic but not pathognomonic eschar is not seen. As the eschar is not always present, laboratory tests are needed for confirmation. Serological assays are the main stay of laboratory diagnosis of scrub typhus thus far. In this review, we present the salient clinical features and clinical algorithms suggestive of this disease that help in better selection of diagnostics. The various scrub typhus assays along with their advantages and disadvantages have also been discussed. Furthermore, we have also discussed the upcoming diagnostics, both serological and molecular assays which can be available in the near future.

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Section: Antibody Detection (Serological Assays)mentioning

confidence: 99%

Section: Antibody Detection (Serological Assays)mentioning

confidence: 99%

Scrub typhus diagnostics: An overview

Bora²,

Perumalla

et al. 2023

Preprint

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“…A patient was treated as a confirmed case of scrub typhus based on a single IgM ELISA OD value of 1.0 or higher in the absence of an alternative, plausible cause of fever. This cut-off has been locally defined for the diagnosis of acute cases in routine clinical practice and validated using the receiver operating characteristic approach in a sample of 346 subjects (scrub typhus cases, other fever cases, healthy controls) [22]. Forty-two patients were excluded despite a positive IgM test due to an unclear or alternative diagnosis (S1 Fig).…”

Section: Blood Testingmentioning

confidence: 99%

High initial IgG antibody levels against Orientia tsutsugamushi are associated with an increased risk of severe scrub typhus infection

et al. 2021

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Background Scrub typhus is a dominant cause of febrile illness in many parts of Asia. Immunity is limited by the great strain diversity of Orientia tsutsugamushi. It is unclear whether previous infection protects from severe infection or enhances the risk. Methods/principal findings We studied IgG antibody levels against O. tsutsugamushi at presentation in 636 scrub typhus patients using enzyme-linked immunosorbent assays (ELISA). The association between ELISA optical density (OD) and risk of severe infection was modelled using Poisson regression. OD was categorised as low (<1.0), intermediate (1.0 to 2.9), and high (≥3.0). OD was also modelled as a continuous variable (cubic spline). Median age of cases was 41 years (range 0–85), with 37% having severe infection. Compared to the low category, the age-adjusted risk of severe infection was 1.5 times higher in the intermediate category (95%CI 1.2, 1.9), and 1.3 times higher in the high category (95%CI 1.0, 1.7). The effect was stronger in cases <40 years, doubling the risk in the intermediate and high categories compared to the low category. The effect was more pronounced in cases tested within 7 days of fever onset when IgG ODs are more likely to reflect pre-infection levels. Conclusions/Significance Intermediate and high IgG antibody levels at the time of diagnosis are associated with a higher risk of severe scrub typhus infection. The findings may be explained by severe infection eliciting an accelerated IgG response or by previous scrub typhus infection enhancing the severity of subsequent episodes.

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Assessment of two immunoassays for detection of IgM antibodies to scrub typhus using a serum panel

Cited by 2 publications

References 26 publications

Scrub typhus diagnostics: An overview

Scrub typhus diagnostics: An overview

High initial IgG antibody levels against Orientia tsutsugamushi are associated with an increased risk of severe scrub typhus infection

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