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Evaluation of a blocking ELISA for the detection of antibodies against Lawsonia intracellularis in pig sera
BACKGROUND: Lawsonia intracellularis is a common cause of chronic diarrhoea and poor performance in young growing pigs. Diagnosis of this obligate intracellular bacterium is based on the demonstration of the microbe or microbial DNA in tissue specimens or faecal samples, or the demonstration of L. i...
Autores principales: | , , , , |
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Formato: | Texto |
Lenguaje: | English |
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BioMed Central
2011
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3080824/ https://www.ncbi.nlm.nih.gov/pubmed/21453555 http://dx.doi.org/10.1186/1751-0147-53-23 |
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author | Jacobson, Magdalena Wallgren, Per Nordengrahn, Ann Merza, Malik Emanuelson, Ulf |
author_facet | Jacobson, Magdalena Wallgren, Per Nordengrahn, Ann Merza, Malik Emanuelson, Ulf |
author_sort | Jacobson, Magdalena |
collection | PubMed |
description | BACKGROUND: Lawsonia intracellularis is a common cause of chronic diarrhoea and poor performance in young growing pigs. Diagnosis of this obligate intracellular bacterium is based on the demonstration of the microbe or microbial DNA in tissue specimens or faecal samples, or the demonstration of L. intracellularis-specific antibodies in sera. The aim of the present study was to evaluate a blocking ELISA in the detection of serum antibodies to L. intracellularis, by comparison to the previously widely used immunofluorescent antibody test (IFAT). METHODS: Sera were collected from 176 pigs aged 8-12 weeks originating from 24 herds with or without problems with diarrhoea and poor performance in young growing pigs. Sera were analyzed by the blocking ELISA and by IFAT. Bayesian modelling techniques were used to account for the absence of a gold standard test and the results of the blocking ELISA was modelled against the IFAT test with a "2 dependent tests, 2 populations, no gold standard" model. RESULTS: At the finally selected cut-off value of percent inhibition (PI) 35, the diagnostic sensitivity of the blocking ELISA was 72% and the diagnostic specificity was 93%. The positive predictive value was 0.82 and the negative predictive value was 0.89, at the observed prevalence of 33.5%. CONCLUSION: The sensitivity and specificity as evaluated by Bayesian statistic techniques differed from that previously reported. Properties of diagnostic tests may well vary between countries, laboratories and among populations of animals. In the absence of a true gold standard, the importance of validating new methods by appropriate statistical methods and with respect to the target population must be emphasized. |
format | Text |
id | pubmed-3080824 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2011 |
publisher | BioMed Central |
record_format | MEDLINE/PubMed |
spelling | pubmed-30808242011-04-22 Evaluation of a blocking ELISA for the detection of antibodies against Lawsonia intracellularis in pig sera Jacobson, Magdalena Wallgren, Per Nordengrahn, Ann Merza, Malik Emanuelson, Ulf Acta Vet Scand Research BACKGROUND: Lawsonia intracellularis is a common cause of chronic diarrhoea and poor performance in young growing pigs. Diagnosis of this obligate intracellular bacterium is based on the demonstration of the microbe or microbial DNA in tissue specimens or faecal samples, or the demonstration of L. intracellularis-specific antibodies in sera. The aim of the present study was to evaluate a blocking ELISA in the detection of serum antibodies to L. intracellularis, by comparison to the previously widely used immunofluorescent antibody test (IFAT). METHODS: Sera were collected from 176 pigs aged 8-12 weeks originating from 24 herds with or without problems with diarrhoea and poor performance in young growing pigs. Sera were analyzed by the blocking ELISA and by IFAT. Bayesian modelling techniques were used to account for the absence of a gold standard test and the results of the blocking ELISA was modelled against the IFAT test with a "2 dependent tests, 2 populations, no gold standard" model. RESULTS: At the finally selected cut-off value of percent inhibition (PI) 35, the diagnostic sensitivity of the blocking ELISA was 72% and the diagnostic specificity was 93%. The positive predictive value was 0.82 and the negative predictive value was 0.89, at the observed prevalence of 33.5%. CONCLUSION: The sensitivity and specificity as evaluated by Bayesian statistic techniques differed from that previously reported. Properties of diagnostic tests may well vary between countries, laboratories and among populations of animals. In the absence of a true gold standard, the importance of validating new methods by appropriate statistical methods and with respect to the target population must be emphasized. BioMed Central 2011-04-01 /pmc/articles/PMC3080824/ /pubmed/21453555 http://dx.doi.org/10.1186/1751-0147-53-23 Text en Copyright ©2011 Jacobson et al; licensee BioMed Central Ltd. http://creativecommons.org/licenses/by/2.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Research Jacobson, Magdalena Wallgren, Per Nordengrahn, Ann Merza, Malik Emanuelson, Ulf Evaluation of a blocking ELISA for the detection of antibodies against Lawsonia intracellularis in pig sera |
title | Evaluation of a blocking ELISA for the detection of antibodies against Lawsonia intracellularis in pig sera |
title_full | Evaluation of a blocking ELISA for the detection of antibodies against Lawsonia intracellularis in pig sera |
title_fullStr | Evaluation of a blocking ELISA for the detection of antibodies against Lawsonia intracellularis in pig sera |
title_full_unstemmed | Evaluation of a blocking ELISA for the detection of antibodies against Lawsonia intracellularis in pig sera |
title_short | Evaluation of a blocking ELISA for the detection of antibodies against Lawsonia intracellularis in pig sera |
title_sort | evaluation of a blocking elisa for the detection of antibodies against lawsonia intracellularis in pig sera |
topic | Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3080824/ https://www.ncbi.nlm.nih.gov/pubmed/21453555 http://dx.doi.org/10.1186/1751-0147-53-23 |
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