Estimation of the sensitivity and specificity of two serum ELISAs and one fecal qPCR for diagnosis of paratuberculosis in sub-clinically infected young-adult French sheep using latent class Bayesian modeling

Mathevon, Yoann; Foucras, Gilles; Falguières, Rémy; Corbière, Fabien

doi:10.1186/s12917-017-1145-x

Cited by 27 publications

(30 citation statements)

References 57 publications

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“…The diagnostic test results from a cross-sectional study were previously published by the study investigators [27]. Briefly, 1197 individual serum and fecal samples were collected from 2- to 3-year-old sheep without clinical signs of paratuberculosis in 14 purebred Causse du Lot closed meat sheep flocks where paratuberculosis infection was endemic.…”

Section: Methodsmentioning

confidence: 99%

“…A commercial serum ELISA (IDEXX paratuberculosis screening kit, batch 5074, IDEXX, Montpellier, France) was applied to individual or pooled serum samples using an overnight incubation protocol following the manufacturer’s instructions, as previoulys described [27].…”

Section: Methodsmentioning

confidence: 99%

“…Individual and pooled fecal samples were submitted to a commercial qPCR protocol targeting the IS900 DNA fragment of Map (Adiafilter and Adiavet ParaTB Real Time, BioX, Rochefort, Belgium) using 10 grams as working material, as previously described [27].…”

Section: Methodsmentioning

confidence: 99%

“…For infected flocks, these estimates were derived from Mathevon et al . (2017) [27] in which the diagnostic accuracy of the IDEXX serum ELISA and the ADIAVET fecal qPCR were estimated in sub-clinically infected sheep using Bayesian modeling. Interested readers are referred to Mathevon et al .…”

Section: Methodsmentioning

confidence: 99%

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Flock sensitivity and specificity of pooled fecal qPCR and pooled serum ELISA for screening ovine paratuberculosis

2019

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The aim of our study was to evaluate the flock sensitivity and specificity of fecal qPCR and serum ELISA using pooled samples for screening paratuberculosis in French sheep.Using individual feces with low or high qPCR Ct values from ewes sampled in 14 infected flocks, a total of 555 pools of size 5, 10 and 20 were created by diluting individual materials in negative feces and analysed using a commercial IS900 qPCR kit. The relative performances of pooled serum ELISA analysis were evaluated based on the analysis of 181 different pools of size 5 and 10, composed of individual serum samples of various individual S/P values. Results showed that for pools of size 5, 10 or 20, individual fecal samples with low Ct values were invariably detected. Conversely fecal samples with high Ct values were associated with a lower detection rate in both pools of size 5 (87.0% to 90.0%), 10 (63.0% to 70.7%) and 20 (46.7% to 60.0%). After lowering the decision threshold to 25% and 15% for serum pools of size 5 and 10 respectively, the pooled serum ELISA relative sensitivity ranged between 62.2% and 100.0% depending on the composition of the pools.Finally, a simulation study was carried out to evaluate the performances of 16 screening strategies at flock level, with varying pool size (5 to 20) and number (5 to 60). The use of pooled serum ELISA led to very false positive detection rate ranging between 37.6% and 91.8% in paratuberculosis free flocks and prevents its further use in that context. For infection prevalence ≤ 5%, the flock sensitivity based on pooled fecal qPCR ranged between 39.0% (5 pools of size 10) and 99.9% (300 sampled individuals, with pools of size 5,10 or20), and was always above 93% when the infection prevalence was greater or equal to 15%. We conclude that pooled-fecal qPCR but not pooled-serum ELISA could be a useful tool to detect sheep flocks infected with paratuberculosis.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Flock sensitivity and specificity of pooled fecal qPCR and pooled serum ELISA for screening ovine paratuberculosis

2019

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“…There are also novel methods for the detection of Klebsiella pneumoniae, which are demonstrated to be more accurate and sensitive, like automatic bacteria identi cation system and mass spectrometry [9]. However, these methods could not be conducted on-site and in low resource-setting areas that lack precise equipment and trained personnel [10]. Furthermore, studies on goat-source Klebsiella pneumoniae are generally focused on isolation, identi cation, and epidemiological investigation while few studies on developing detection methods.…”

Section: Introductionmentioning

confidence: 99%

Establishment and Evaluation of an Indirect ELISA for Detection of Antibodies to Goat Klebsiella Pneumonia

Chen¹,

Shang

Niu

et al. 2020

Preprint

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Background: Klebsiella pneumonia, a Gram-negative bacterium belonging to the genus Enterobacter, causes many human and livestock diseases. Notably, infected goats may develop pneumonia, septicemia, which can lead to occasional death, resulting in great economic losses in goat-farming industry. However, there are no systematic methods for detection of Klebsiella pneumoniae in goats currently. Results: In this study, we developed a Klebsiella pneumoniae goat polyclonal antibody and established an indirect ELISA method to detect the Klebsiella pneumoniae. After screening and optimizing the conditions for detection, we determined the optimal working dilutions of the coated-bacterial antigen, the polyclonal antibody, and the enzyme-labeled secondary antibody that were 1:800 (2.99x107 CFU/ml), 1:6400, and 1:5000, respectively. The optimal condition of coating and blocking were both 4 °C for 12 h. The optimal dilution buffers of bacterial antigen, the antibodies, and the blocking buffer were 0.05 mol/L carbonate buffer, 1% BSA phosphate buffer, and 1.5% BSA carbonate buffer, respectively. The cut-off value was determined to be 0.28, and the analytical sensitivity was 1:800. Furthermore, there was no cross-reaction between the coated antigen and goat serum positive for other common bacteria, indicating that indirect ELISA could detect Klebsiella pneumoniae specifically in most cases. The average coefficients of variation of intra-assay and inter-assay were 4.37% and 5.17% indicating favorable reproducibility of indirect ELISA. In the detection of clinical veterinary samples, the positive rate of indirect ELISA was 6.74%, higher than that of conventional agglutination assays. Conclusions: Taken together, our results suggested that the method that we established has promising applications in production, laying the foundation for epidemiology, serological investigation and clinical veterinary diagnosis of Klebsiella pneumoniae in goats.

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Estimating prevalence and test accuracy in disease ecology: How Bayesian latent class analysis can boost or bias imperfect test results

Helman

Mummah

Gostic

et al. 2020

Ecology and Evolution

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Obtaining accurate estimates of disease prevalence is crucial for the monitoring and management of wildlife populations but can be difficult if different diagnostic tests yield conflicting results and if the accuracy of each diagnostic test is unknown. Bayesian latent class analysis (BLCA) modeling offers a potential solution, providing estimates of prevalence levels and diagnostic test accuracy under the realistic assumption that no diagnostic test is perfect. In typical applications of this approach, the specificity of one test is fixed at or close to 100%, allowing the model to simultaneously estimate the sensitivity and specificity of all other tests, in addition to infection prevalence. In wildlife systems, a test with near‐perfect specificity is not always available, so we simulated data to investigate how decreasing this fixed specificity value affects the accuracy of model estimates. We used simulations to explore how the trade‐off between diagnostic test specificity and sensitivity impacts prevalence estimates and found that directional biases depend on pathogen prevalence. Both the precision and accuracy of results depend on the sample size, the diagnostic tests used, and the true infection prevalence, so these factors should be considered when applying BLCA to estimate disease prevalence and diagnostic test accuracy in wildlife systems. A wildlife disease case study, focusing on leptospirosis in California sea lions, demonstrated the potential for Bayesian latent class methods to provide reliable estimates under real‐world conditions. We delineate conditions under which BLCA improves upon the results from a single diagnostic across a range of prevalence levels and sample sizes, demonstrating when this method is preferable for disease ecologists working in a wide variety of pathogen systems.

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Estimation of the sensitivity and specificity of two serum ELISAs and one fecal qPCR for diagnosis of paratuberculosis in sub-clinically infected young-adult French sheep using latent class Bayesian modeling

Cited by 27 publications

References 57 publications

Flock sensitivity and specificity of pooled fecal qPCR and pooled serum ELISA for screening ovine paratuberculosis

Flock sensitivity and specificity of pooled fecal qPCR and pooled serum ELISA for screening ovine paratuberculosis

Establishment and Evaluation of an Indirect ELISA for Detection of Antibodies to Goat Klebsiella Pneumonia

Estimating prevalence and test accuracy in disease ecology: How Bayesian latent class analysis can boost or bias imperfect test results

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