Ante mortem diagnosis of paratuberculosis: A review of accuracies of ELISA, interferon-γ assay and faecal culture techniques

Department of Large Animal Sciences, Faculty of Life Sciences, University of Copenhagen, Frederiksberg C, Denmark.
Veterinary Microbiology (Impact Factor: 2.51). 07/2008; 129(3-4):217-35. DOI: 10.1016/j.vetmic.2007.12.011
Source: PubMed


Infections with Mycobacterium avium subsp. paratuberculosis (MAP) can be latent for years without affecting the animal, but the animal may become infectious or clinical at some point. Diagnosis of paratuberculosis can be a challenge primarily in latent stages of the infection, and different diagnosis interpretations are usually required by the variety of decision makers. The objective of this paper was to provide a critical review of reported accuracies of ELISA tests, interferon-gamma assays (IFN-gamma) and faecal culture (FC) techniques used for diagnosis of three defined target conditions: MAP infected, MAP infectious and MAP affected animals. For each animal species, target condition and diagnostic test-type, sensitivities (Se) and specificities (Sp) were summarised based on a systematic, critical review of information in literature databases. The diagnostic test information often varied substantially for tests of the same type and make, particularly ELISA, which was the most frequently reported test-type. Comparison of the various tests accuracies was generally not possible, but stratification of test-evaluations by target condition improved the interpretation of the test accuracies. Infectious and affected animals can often be detected, but Se for infected animals is generally low. A main conclusion of the review was that the quality of design, implementation and reporting of evaluations of tests for paratuberculosis is generally poor. Particularly, there is a need for better correspondence between the study population and target population, i.e. the subjects chosen for test evaluation should reflect the distribution of animals in the population where the test is intended to be used.

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Available from: Søren Saxmose Nielsen, Aug 14, 2015
    • "paratuberculosis (MAP) (Sweeney, 2011). A MAP infection may be latent for the major part of an animal's life, or infection may develop to infectious and affected disease states (Nielsen and Toft, 2008). The possibility for latent infection makes diagnostic misclassification a general challenge. "
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    ABSTRACT: Paratuberculosis is a chronic infection of economic importance to the dairy industry. The infection may be latent for years, which makes diagnostic misclassification a general challenge. The objective of this study was to identify the spatial pattern in infection prevalence, when results were adjusted for covariate information and diagnostic misclassification. Furthermore, we compared the estimated spatial pattern with the spatial pattern obtained without adjustment for misclassification. The study included 1242 herds in 2009 and 979 herds in 2013. The within-herd prevalence was modelled using a hierarchical logistic regression model and included a spatial component modelled by a continuous Gaussian field. The Stochastic Partial Differential Equation (SPDE) approach and Integrated Nested Laplace Approximation (INLA) were used for Bayesian inference. We found a significant spatial component, and our results suggested that the estimated range of influence and the overall location of areas with increased prevalence are not very sensitive to diagnostic misclassification.
    Spatial and Spatio-temporal Epidemiology 10/2015; DOI:10.1016/j.sste.2015.10.001
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    • "The disease has a slowly progressing detrimental effect on cow health and production. The progression of the disease can be categorized into multiple stages (Whitlock et al., 2000; Collins, 2002; Nielsen and Toft, 2008); however, based on their potential of transmitting MAP infection to susceptible cattle, a population can be categorized into 3 groups (Crossley et al., 2005): (1) Non-shedding cows. Although most animals in this group may not be infected with MAP, a proportion of them could be infected and in the latent stage of the disease. "
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    ABSTRACT: The objective of this study was to evaluate the performance of bacterial culture of feces and serum ELISA to correctly identify cows with Mycobacterium avium ssp. paratuberculosis (MAP) at heavy, light, and non-fecal-shedding levels. A total of 29,785 parallel test results from bacterial culture of feces and serum ELISA were collected from 17 dairy herds in Minnesota, Pennsylvania, and Colorado. Samples were obtained from adult cows from dairy herds enrolled for up to 10 yr in the National Johne's Disease Demonstration Herd Project. A Bayesian latent class model was fitted to estimate the probabilities that bacterial culture of feces (using 72-h sedimentation or 30-min centrifugation methods) and serum ELISA results correctly identified cows as high positive, low positive, or negative given that cows were heavy, light, and non-shedders, respectively. The model assumed that no gold standard test was available and conditional independency existed between diagnostic tests. The estimated conditional probabilities that bacterial culture of feces correctly identified heavy shedders, light shedders, and non-shedders were 70.9, 32.0, and 98.5%, respectively. The same values for the serum ELISA were 60.6, 18.7, and 99.5%, respectively. Differences in diagnostic test performance were observed among states. These results improve the interpretation of results from bacterial culture of feces and serum ELISA for detection of MAP and MAP antibody (respectively), which can support on-farm infection control decisions and can be used to evaluate disease-testing strategies, taking into account the accuracy of these tests.
    Journal of Dairy Science 09/2015; 98(11). DOI:10.3168/jds.2014-8440 · 2.57 Impact Factor
    • "After in utero or fecal-oral infection, cattle go through an extended incubation period that can ultimately result in development of Johne's disease, a noncurable enteritis (Sweeney , 2011). During incubation, infected cattle frequently remain undetected because antibody production and bacterial shedding occur only intermittently (Mortier et al., 2014a,b), and available tests lack accuracy (Nielsen and Toft, 2008), thereby reducing the effectiveness of testing and culling for successful eradication of MAP on cattle farms (Whitlock and Buergelt, 1996; Garry, 2011). As a consequence, most MAP-control programs are not solely based on testing and culling, but encourage implementation of best management practices to prevent MAP introduction and transmission between infectious and susceptible cattle (McKenna et al., 2006). "
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    ABSTRACT: The Alberta Johne's Disease Initiative (AJDI) is a voluntary, management-based prevention and control program for Johne's disease (JD), a wasting disease in ruminants that causes substantial economic losses to the cattle industry. Despite extensive communication about the program's benefits and low cost to participating producers, approximately 35% of Alberta dairy farmers have not enrolled in the AJDI. Therefore, the objective was to identify differences between AJDI nonparticipants and participants that may influence enrollment. Standardized questionnaires were conducted in person on 163 farms not participating and 61 farms participating in the AJDI. Data collected included demographic characteristics, internal factors (e.g., attitudes and beliefs of the farmer toward JD and the AJDI), external factors (e.g., farmers' JD knowledge and on-farm goals and constraints), as well as farmers' use and influence of various information sources. Nonparticipants and participants differed in at least some aspects of all studied categories. Based on logistic regression, participating farms had larger herds, higher self-assessed knowledge of JD, better understanding of AJDI details before participation, and used their veterinarian more often to get information about new management practices and technologies when compared with nonparticipants. In contrast, nonparticipants indicated that time was a major on-farm constraint and that participation in the AJDI would take too much time. They also indicated that they preferred to wait and see how the program worked on other farms before they participated. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
    Journal of Dairy Science 09/2015; 98(11). DOI:10.3168/jds.2015-9789 · 2.57 Impact Factor
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