Calculation of the ELISA’s cut-off based on the change-point analysis method for detection of Trypanosoma cruzi infection in Bolivian dogs in the absence of controls

Lardeux, Frédéric; Torrico, Gino; Aliaga, Claudia

doi:10.1590/0074-02760160119

Cited by 102 publications

(91 citation statements)

References 13 publications

(16 reference statements)

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“…To establish cut-off values for IgM and IgG of each antigen, values from healthy category were used. Cut-off values were established by adding mean of all average OD values to three times the standard deviation of all average OD values 79 , 80 . In the next step, an optical density index (ODI) dataset was created for all patient categories by dividing average OD values of microbes by their respective cut-off values.…”

Section: Methodsmentioning

confidence: 99%

RETRACTED ARTICLE: Evaluating polymicrobial immune responses in patients suffering from tick-borne diseases

Garg

Meriläinen

Franz

et al. 2018

Sci Rep

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There is insufficient evidence to support screening of various tick-borne diseases (TBD) related microbes alongside Borrelia in patients suffering from TBD. To evaluate the involvement of multiple microbial immune responses in patients experiencing TBD we utilized enzyme-linked immunosorbent assay. Four hundred and thirty-two human serum samples organized into seven categories followed Centers for Disease Control and Prevention two-tier Lyme disease (LD) diagnosis guidelines and Infectious Disease Society of America guidelines for post-treatment Lyme disease syndrome. All patient categories were tested for their immunoglobulin M (IgM) and G (IgG) responses against 20 microbes associated with TBD. Our findings recognize that microbial infections in patients suffering from TBDs do not follow the one microbe, one disease Germ Theory as 65% of the TBD patients produce immune responses to various microbes. We have established a causal association between TBD patients and TBD associated co-infections and essential opportunistic microbes following Bradford Hill’s criteria. This study indicated an 85% probability that a randomly selected TBD patient will respond to Borrelia and other related TBD microbes rather than to Borrelia alone. A paradigm shift is required in current healthcare policies to diagnose TBD so that patients can get tested and treated even for opportunistic infections.

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Section: Methodsmentioning

confidence: 99%

RETRACTED ARTICLE: Evaluating polymicrobial immune responses in patients suffering from tick-borne diseases

Garg

Meriläinen

Franz

et al. 2018

Sci Rep

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“…Receiver operating characteristic (ROC) curve analysis [11] and a World Organisation for Animal Health (OIE) recommended tool [12] were commonly used to optimize the cutoff values in ELISAs to find the best correlation for sensitivity (Se) and specificity (Sp) [13][14][15][16]. Some other methods to estimate the cutoff values are (1) mean value plus three standard deviations of negative controls [17]; (2) Cuto f f = Xneg + 0.13 Xpos where X is the mean [18,19] and (3) Cuto f f = X + f SD" with f = t 1 + 1 n [19,20]. These methods are based on values obtained with negative sera.…”

Section: Introductionmentioning

confidence: 99%

Performance Analysis of Anaplasma Antibody Competitive ELISA Using the ROC Curve for Screening of Anaplasmosis in Camel Populations in Egypt

Parvizi

El-Adawy

Roesler³

et al. 2020

Pathogens

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Anaplasmosis is a tick-born and potential zoonotic disease caused by Anaplasma (A.) phagocytophilum, A. ovis, A. platys and A. capra. Anaplasma marginale affecting bovines and camels causing significant economic losses. Camels as an integral part of the socio-economic lifestyle of nomads in semi-arid to arid ecosystems are prone to suffer from subclinical Anaplasma infections. This study aimed to determine the performance and adaptation of commercial competitive Anaplasma ELISA (cELISA) as a tool for screening the seroprevalence of anaplasmosis whitin the camel populations in Egypt. This study was based on the serological investigation of 437 camel sera collected between 2015 and 2016 during a Q fever prevalence study in Egypt using commercially available cELISA for the detection of antibodies specific for Anaplasma in bovine serum. The receiver operating characteristic (ROC) curve, an analysis method for optimizing cutoff values in cELISAs, was used to estimate the sensitivity and specificity using 76 true as serological positive (n = 7) and negative (n = 60) for Anaplasma antibodies. ROC curve analysis was done for 7 true positive and 60 true negative bovine samples and 7 true positive and 29 true negative camel samples serum. Real time PCR and/or conventional PCR was applied to confirm Anaplasma spp. specific-DNA in camel serum as an indication of a true positive and true negative for ROC analysis. Chi square analysis was performed to estimate the association between risk factors and anaplasmosis in camels. The cutoff value was determined as 0.42 (p value ≤ 0.001). Data simulation with randomly generated values revealed a cutoff value of 0.417 (p ≤ 0.001) with resulting 58.1% Se and 97.8% Sp. Seven true positive and 29 true negative camel serum samples was confirmed by PCR. Using the estimated cut off, the seroprevalence in the Nile Valley and Delta and the Eastern Desert domain was 47.4% and 46.4%, respectively. The potential risk factors as domains and origin of animals were less significantly associated with the prevalence of anaplasmosis (domains: χ(2) = 41.8, p value ≤ 0.001 and origin: χ(2) = 42.56, p value ≤ 0.001). Raising awareness especially for veterinarians and animal owners will significantly contribute to the best understanding of anaplasmosis in camels in Egypt. Alternative (in silico) validation techniques and preliminary prevalence studies are mandatory towards the control of neglected anaplasmosis in the camel population.

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“…Change‐point analysis detects abrupt steps in the mean level of a series so that seropositive and seronegative OD corrected values would be separated by a step in the series. This approach is an efficient alternative to the usual cut‐off formula of the form “mean + 3 standard deviations of the known negative controls” (Lardeux, Torrico, & Aliaga, ). We used the R package “changepoint” (Killick & Eckley, ) and selected the Pruned Exact Linear Time (PELT) algorithm to detect change‐points (Development Core Team, ; Killick, Fearnhead, & Eckley, ).…”

Section: Methodsmentioning

confidence: 99%

Arousal from hibernation and reactivation ofEptesicus fuscusgammaherpesvirus (EfHV) in big brown bats

Gerow

Rapin

Voordouw

et al. 2018

Transbound Emerg Dis

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Many viruses that cause serious and often fatal disease in humans have spilled over from bats. Recent evidence suggests that stress may enhance virus shedding by bats increasing the possibility of transmission to other species. To understand the reasons for spillover is therefore important to determine the molecular pathways that link stress to virus reactivation and shedding in bats. We recently isolated and characterized a gammaherpesvirus (Eptesicus fuscus herpesvirus, EfHV) autochthonous to North American big brown bats. Since herpesviruses are known to reactivate from latent infections in response to a wide variety of stressors, EfHV presents us with an opportunity to study how physiological, behavioural or environmental changes may influence the big brown bats’ relationship with EfHV. To understand the biology of the virus and how the extended periods of torpor experienced by these bats during hibernation along with the stress of arousal might influence the virus‐host relationship, we attempted to detect the virus in the blood of wild‐caught non‐hibernating bats as well as captive bats arising from hibernation. We compared the prevalence of EfHV in the blood (using PCR) and EfHV‐specific antibodies (using ELISA) between captive hibernating bats and wild‐caught non‐hibernating bats. We detected EfHV only in the blood of captive hibernating bats (27.8% = 10/36) and not in wild‐caught non‐hibernating bats (0.0% = 0/43). In contrast, the EfHV‐specific antibody titres were higher in the non‐hibernating bats compared to the hibernating bats. Our study suggests that: (a) viral DNA in blood indicates reactivation from latency, (b) long periods of hibernation lead to suppression of immunity, (c) stress of arousal from hibernation reactivates the virus in bats with lower levels of anti‐viral immunity (indicated by humoral immune response), and (d) levels of anti‐viral immunity increase in non‐hibernating bats following reactivation.

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Calculation of the ELISA’s cut-off based on the change-point analysis method for detection of Trypanosoma cruzi infection in Bolivian dogs in the absence of controls

Cited by 102 publications

References 13 publications

RETRACTED ARTICLE: Evaluating polymicrobial immune responses in patients suffering from tick-borne diseases

RETRACTED ARTICLE: Evaluating polymicrobial immune responses in patients suffering from tick-borne diseases

Performance Analysis of Anaplasma Antibody Competitive ELISA Using the ROC Curve for Screening of Anaplasmosis in Camel Populations in Egypt

Arousal from hibernation and reactivation ofEptesicus fuscusgammaherpesvirus (EfHV) in big brown bats

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