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Modeling the effect of test-and-slaughter strategies to control bovine tuberculosis in endemic high prevalence herds
  • +4
  • Catalina Picasso Risso,
  • Julio Alvarez,
  • Kimberly VanderWaal,
  • Amy Kinsley,
  • Andres Gil,
  • Scott Wells,
  • Andres Perez
Catalina Picasso Risso
University of Minnesota
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Julio Alvarez
Universidad Complutense de Madrid
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Kimberly VanderWaal
University of Minnesota Twin Cities
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Amy Kinsley
University of Minnesota
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Andres Gil
Universidad de la Republica Uruguay Facultad de Veterinaria
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Scott Wells
College of Veterinary Medicine, University of Minnesota
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Andres Perez
University of Minnesota
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Peer review status:ACCEPTED

21 May 2020Submitted to Transboundary and Emerging Diseases
23 May 2020Submission Checks Completed
23 May 2020Assigned to Editor
29 May 2020Reviewer(s) Assigned
18 Jul 2020Review(s) Completed, Editorial Evaluation Pending
18 Jul 2020Editorial Decision: Revise Minor
30 Jul 20201st Revision Received
31 Jul 2020Submission Checks Completed
31 Jul 2020Assigned to Editor
31 Jul 2020Reviewer(s) Assigned
01 Aug 2020Review(s) Completed, Editorial Evaluation Pending
02 Aug 2020Editorial Decision: Accept

Abstract

Bovine tuberculosis (bTB) prevalence substantially increased over the past two decades with relatively high impact on large dairy herds, raising the concern of regulatory authorities and industry stakeholders, and threatening animal and public health. Lack of resources, together with the economic and social consequences of whole-herd stamping-out, makes depopulation an impractical disease control alternative in these herds. The increase in bTB-prevalence was associated with demographic and management changes in the dairy industry in Uruguay, reducing the efficacy of the current control program (i.e. status quo) based on intradermal serial testing with caudal fold- and comparative cervical- tuberculin test-and slaughter of reactors (CFT-CCT). Here, we aimed to assess the epidemiological effectiveness of six alternative control scenarios based on test-and-slaughter of positive animals, using mathematical modeling to infer bTB-within-herd dynamics. We simulated six alternative control strategies consisting of testing adult cattle (>1 year) in the herd every three months using one test (in-vivo or in-vitro) or a combination in parallel of two tests (CFT, interferon-gamma release assay –IGRA- or Enzyme-linked immunosorbent assay). Results showed no significant differences overall in the time needed to reach bTB-eradication (median ranging between 61 to 82 months) or official bovine tuberculosis-free status (two consecutive negative herd-tests) between any of the alternative strategies and the status quo (median ranging between 50 and 59 months). However, we demonstrate how alternative strategies can significantly reduce bTB-prevalence when applied for restricted periods (6, 12, or 24 months), and in the case of IGRAc (IGRA using peptide-cocktail antigens), without incurring on higher unnecessary slaughter of animals (false-positives) than the status quo in the first 6 months of the program (P-value <0.05). Enhanced understanding bTB-within-herd dynamics with the application of different control strategies help to identify optimal strategies to ultimately improve bTB-control and -eradication from dairies in Uruguay and similar endemic settings.