Bluetongue Epidemiological report published
8 May 2008
A report exploring the spread of BTV8 up to the period of the 15 March (to the end of the VFP) has been published by Defra today, 8 May.
It uses data gathered during disease tracings investigations, pre-movement testing during the vector free period and surveillance testing around infected premises and import testing of animals from Europe to areas of the UK.
This is an initial report and the data used in its conclusions were not designed to be used for epidemiological findings thus the conclusions of this report do contain a level of uncertainty.
Throughout this report, the original PZ in East Anglia is referred to PZ1 whilst the PZ around Poole in Dorset is referred to as PZ2.
Bluetongue is likely to have become widespread in PZ1 during 2007, with many holdings affected. The likelihood of infection of susceptible animals does however reduce as you move in an east to west direction across the country, however, the report suggests that the western boundary of PZ1 should be extended, or at least treated with caution.
This cautionary approach is being addressed by the vaccine rollout plan with high degrees of priority being given to areas immediately to the western boundary of PZ1.
A single infected animal was identified by pre-movement testing on a farm in the Poole area. Over 1,000 animals, within 10km of the infected premise, have since been tested - all returning negative results.
The report suggests therefore that BTV8 is not widespread in PZ2, although presents several hypothesis for how BTV8 reached the IP, including illegal animal movements, an unlucky bite by one 'stray' but infected midge on one animal and a possible wind incursion from France. Further work is underway to refute or confirm these various suggestions.
