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ANNEX 1 (b) Economics outputs
BTV8 Incursion x Control Matrix as discussed at the expert meeting on 5th February 2008, SAC, Edinburgh, last modified 27/2/08
Incursion Control Scenario | Incursion a South-April 09
(Midge) Prob=Ra | Incursion b South-July 08
(Midge) Prob=Rb | Incursion c South-Sept. 08
(Midge) Prob=Rc | Incursion d Animal import
April 09 Prob=Rd | Incursion e Animal import
September 08 Prob=Re |
1. Do nothing (control cost = c1=0) outcome = C1 or counterfactual (minimum required response) | Expected loss=RaC1a | Expected loss=RbC1b | Expected loss=RcC1c | Expected loss=RdC1d | Expected loss=ReC1e |
Control zone options: 2. Border PZ - 100% vaccinated at cost=c2 | Expected loss=RaC2a | Expected loss=RbC2b | Expected loss=RcC2c | Expected loss=RdC2d | Expected loss=ReC2e* |
| 3. PZ to Highland B/F line - 80% vaccinated at cost=c3 | Expected loss=RaC3a | Expected loss=RbC3b | Expected loss=RcC3c | Expected loss=RdC3d | Expected loss=ReC3e* |
| 4. PZ all Scotland - 50% vaccinated at cost = c4 | Expected loss=RaC4a | Expected loss=RbC4b | Expected loss=RcC4c | Expected loss=RdC4d | Expected
Loss=ReC4e |
| 5. 100km PZ around incursion above the Highland B/F line - 80% vaccinated at cost = c5 | NA* | NA* | NA* | NA* | Expected Loss=ReC5e |
Benefit (b/c ratio) | | | | | |
B2 = R(C1 - C2)/c2 |
B3 = R(C1 - C3)/c3 |
Bn = R(C1 - Cn)/cn |
*See note 4.
Notes:
1. Five incursion scenarios a, b, c, d and e with probability of occurrence of Ra, Rb, Rc, Rd and Re respectively. Incursions a, b and c assume that BTV8 arrives in Scotland via wind blown midges originating in the south. Note that the April incursions are assumed to take place in April 2009.
2. Four main control strategies 1, 2, 3 and 4 with costs c1, c2, c3 and c4. Strategy 1 is the counterfactual i.e. no control scenario i.e. c1=0. This scenario DOES include the minimum required control, i.e. movement restrictions but no vaccination. Where incursion takes place in April 2009 (incursions a and d) vaccination is assumed to take place BEFORE incursion i.e. in January 2009 (when animals are likely to be more accessible). For the other incursions vaccination takes place AFTER initial detection of the incursion. An extra treatment (5) is included to cover the special case of incursion (e) where vaccine location depends on place on incursion (see note 4).
3. Expected output losses are C1, C2, C3 and C4 for control strategies 1 to 4 respectively. These will depend on the incursion scenario under test, e.g. C1a, C1b, C2c etc.
4. Our control strategies are based on an RZ with a CZ, PZ (either Border, Highland B/F line, whole of Scotland or 100km round Northern import) and SZ, and we do compulsory (100%) vaccination within a temporary CZ (put in place for vaccination purposes only around any new IP) and assume 100%, 80% or 50% uptake in the rest of the PZ for strategies 2, 3 and 4 respectively. In the case of incursion e (import in September 2008) the PZ would be established depending on where the incursion takes place. If the incursion takes place within the Border PZ, then option 2 is to be used. If the incursion takes place South of the Highland B/F line, control strategy 3 is put in place, and if the incursion takes place North of the Highland B/F line, then a 100km PZ is established around the holding where the incursion occurred, and 80% uptake is assumed within this PZ. In line with the other vaccination options, a 20km CZ will also be established around the incursion with 100% vaccination. Therefore a fifth control strategy 5e will complement options 2e and 3e, in the case of a Northern import. This gives 21 incursion x control scenarios.
5. We assume that the probability of a particular incursion e.g. Ra is independent of the control strategy in place i.e. control strategies limit the damage (Cn) from a possible incursion not the probability of incursion.
6. It may be difficult to separate output losses Cn from control expenditure cn. For example, declaration of a PZ in order to use vaccine (cn) will trigger movement restrictions and extra surveillance costs (cn) even in the absence of BTV. However, subsequent incursion will require additional movement and trade restrictions and extra surveillance costs (Cn) as well as farm-level output losses due to the disease (Cn).
7. The BTV epidemic model will generate output for year 1 and 2 only. Expert input on 5th Feb indicated that by year 5 the disease will have naturally declined. We will therefore extrapolate year 2 costs into years 3 to 5, assuming a decline to 0 by end of year 5. This assumption will be highlighted as a caveat in the report. All model runs start in January of the year of incursion, i.e. 2008 for incursions b, c and e or 2009 for incursions a and d.
8. The analysis is confined to BTV8. (Again to be reported as a caveat in the report).
9. The levels of vaccination uptake in the above control scenarios 2, 3 and 4 assume a compulsory vaccination scheme, voluntary vaccination scheme with extensive industry uptake and voluntary vaccination scheme with less industry uptake respectively. We will assume that promotion costs (supplied by SG) will be the same for each voluntary vaccination control scenario.
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