Markov events for SORI(V) stochastic transmission model.

<p>Markov events for SORI(V) stochastic transmission model.</p

Age stratified probability of reactors with visible lesions/culture positive (<i>P</i>_<i>VL</i>(<i>ɑ</i>)).

<p>Age stratified probability of reactors with visible lesions/culture positive (<i>P</i>_<i>VL</i>(<i>ɑ</i>)).</p

Epidemiological target measures for ABC.

<p>Epidemiological target measures for ABC.</p

Break-even points for vaccine efficacy under alternative testing scenarios using γ-DIVA test.

<p>We estimate the break-even point for a protective benefit of BCG vaccination at the herd level under three alternative testing scenarios. We model DIVA testing using parameter estimates that optimize DIVA specificity of 99.4% under the constraint of maintaining a DIVA sensitivity comparable to tuberculin testing of 64.4%. We consider four key measures of the epidemiological, and economic, costs associated with bTB testing: <b>A</b> the number of animals condemned as reactors; <b>B</b> the number of tests (tuberculin and DIVA) needed to clear restrictions; <b>C</b> The number of infected animals left in herds after restrictions are lifted (burden of infection missed by testing) <b>D</b> The number of herds that experience a breakdown before the herd clears the singleton challenge. For all panels, solid black lines indicate the median break-even point for the baseline scenario with no vaccination. Dashed lines indicate the 95% quantiles of the baseline scenario. The distribution for each measure is calculated from 100 simulations with parameters drawn from the (approximate) posterior distributions of our estimated model, with each parameter set simulated once for each herd within our representative study population (of 6,601 herds).</p

Age-stratified patterns of reactors in Great Britain.

<p><b>A</b> The relative risk of infection by age RR(a) measured relative to the risk for 0–1 year old cattle, Error bars denote 95% credible intervals. RR(a) is calculated as the ratio of the force of infection for each age group divided by the estimate for the 0–1 year old group. The force of infection is a combined estimate for all national herds (beef and dairy) calculated from reactor cattle reported between 2004–2009 as described in [<a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1004038#pcbi.1004038.ref021" target="_blank">21</a>]. <b>B</b> The probability of “confirmation” of reactor animals by the presence of visible lesions or culture as a function of age at slaughter, estimated as the proportion of reactor animals within each (200 day) age-class that demonstrated visible lesions or a positive culture result. Estimates are calculated using all reactor animals from within our study population of herds. The qualitative pattern is robust between different test-types and parish testing intervals [<a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1004038#pcbi.1004038.ref021" target="_blank">21</a>].</p

Prior distributions.

<p>Prior distributions.</p

Vaccination model parameters.

<p>Vaccination model parameters.</p

Persistence and surveillance metrics for bTB in GB herds (2003–2011).

<p>Within-herd measures of persistence and surveillance used as target metrics for ABC and to assess model fit. We present four key measures, from left to right: the proportion of prolonged (restrictions of greater duration than 240 days) and recurrent breakdowns, the proportion of herds with evidence of visible lesions and the total number of reactors per breakdown. Breakdowns are classified as either OTF-S (officially TB free suspended), where no reactors are found to have visible lesions (lime green circles), or OTF-W (officially TB free withdrawn) where at least one reactor was found to have evidence of visible lesions or be culture positive (magenta squares). The proportion of such OTF-W breakdowns is shown along with the proportion of these that were initiated by a slaughterhouse case (black circles). The relationship of each measure with herd size is plotted, with breakdowns further stratified by the historical parish testing interval (A, PTI1; B, PTI 2; C PTI 4) and breakdown status. Mean target observations are plotted with uncertainty estimated as ±1.96 standard errors around the mean. Predictive distributions from our within-herd (SORI) model for each of these measures are plotted as shaded density strips where the intensity of color is proportional to the probability density at that point [<a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1004038#pcbi.1004038.ref034" target="_blank">34</a>].</p

Markov events for SOR(V) stochastic transmission model.

<p>Markov events for SOR(V) stochastic transmission model.</p

SORI model fit to age-distributions of reactors.

<p>SORI model predictive distributions for the age of reactors (<b>A</b>). Age of “confirmed” reactors with evidence of visible lesions (<b>B</b>). Slaughterhouse cases (<b>C</b>) and the proportion of animals with visible lesions stratified by age (<b>D</b>). Solid points and lines indicate empirical target distributions, model predictive distributions are once again overplotted as shaded density strips where the intensity of color is proportional to the probability density at that point [<a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1004038#pcbi.1004038.ref034" target="_blank">34</a>].</p