Institute of Tropical Medicine Antwerp
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A Bayesian approach for estimating values for prevalence and diagnostic test characteristics of porcine cysticercosis

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Show simple item record Dorny, P. en_US Phiri, I. K. en_US Vercruysse, J. en_US Gabriel, S. en_US Willingham, A. L. en_US Brandt, J. en_US Victor, B. en_US Speybroeck, N. en_US Berkvens, D. en_US 2007-12-06T14:36:00Z 2007-12-06T14:36:00Z 2004 en_US
dc.identifier.issn 0020-7519 en_US
dc.identifier.other ITG-A1A en_US
dc.identifier.other ITG-A6A en_US
dc.identifier.other ITG-A7B en_US
dc.identifier.other ITG-A8A en_US
dc.identifier.other ITG-ALA en_US
dc.identifier.other ANIMAL en_US
dc.identifier.other U-ANIMAL en_US
dc.identifier.other JIF en_US
dc.identifier.other DOI en_US
dc.identifier.other ABSTRACT en_US
dc.description.abstract Several diagnostic techniques are used to estimate the prevalence of the zoonotic tapeworm Taenia solium in pigs, but none of these tests are perfect, making interpretation of results difficult. A Bayesian approach was used to estimate values for the prevalence and diagnostic test characteristic of porcine cysticercosis by combining results of four imperfect tests. Village pigs (N = 868) slaughtered in Lusaka (Zambia), were bled, and tongue and routine meat inspected; and serum antibody and parasite antigen concentrations were determined by ELISA. A model, based on a multinomial distribution and including all possible interactions between the individual tests required 31 parameters to be estimated, but actually allowed only 15 parameters (i.e. had 15 degrees of freedom) to be estimated. Therefore, prior expert opinion on specificity and (in)-dependence of the tests was entered in the model, resulting in a reduction of the number of parameters to be estimated. The estimated prevalence of porcine cysticercosis was 0.642 (95% confidence interval 0.54-0.91). The performances of the tests were (sensitivity (se)-specificity (sp)): tongue inspection (se 0.210-sp 1.000), meat inspection (se 0.221-sp 1.000), Ab-ELISA (se 0.358-sp 0.917), Ag-ELISA (se 0.867-sp 0.947). To validate the estimates obtained from the model we performed a second study: 65 randomly purchased Zambian village pigs were bled for serum antibody and antigen determination, their tongue and meat inspected; and in addition, the carcasses were dissected for total cysticercus counts (gold standard). Cysticerci were found in 31 pigs (prevalence 0.477, 95% confidence interval 0.35-0.60), overlapping with the estimated prevalence in the first study. Sensitivity and specificity values obtained for the aforementioned tests in this study were in agreement with those estimated. A Bayesian analysis framework offers the possibility to combine prior opinion with experimental data to more accurately estimate the real prevalence of porcine cysticercosis in the absence of a gold standard. en_US
dc.language English en_US
dc.subject Animal diseases en_US
dc.subject Helminthic diseases en_US
dc.subject Cysticercosis en_US
dc.subject Taenia solium en_US
dc.subject Pigs en_US
dc.subject Prevalence en_US
dc.subject Estimation en_US
dc.subject Methodology en_US
dc.subject Bayes theorem en_US
dc.subject Laboratory diagnosis en_US
dc.subject Laboratory techniques and procedures en_US
dc.subject Sensitivity en_US
dc.subject Specificity en_US
dc.subject Zambia en_US
dc.subject Africa, Southern en_US
dc.title A Bayesian approach for estimating values for prevalence and diagnostic test characteristics of porcine cysticercosis en_US
dc.type Article en_US
dc.citation.issue 5 en_US
dc.citation.jtitle International Journal for Parasitology en_US
dc.citation.volume 34 en_US
dc.citation.pages 569-576 en_US
dc.citation.jabbreviation Int J Parasitol en_US

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