THE GOAT VETERINARY SOCIETY |
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2009 DISEASE SITUATION
The only reports of disease so far are from France where so far this year there have been 14 holdings positive to BTV8 and 30 to BTV1, though some of those may be surveillance cases picking up a remnant of last year’s infection.
A SOBERING STATISTIC.
In Belgium in 2007 27% of the national sheep flock was infected, and of those 40% died.
OTHER POINTS. The Q & Asessions
Chris Oura suggested that eradication would only be achieved after a HIGH level uptake of vaccine for at least 3 or 4 years. A level of vaccine below 60% will lead to infection being present for many years. Current uptake in the UK not known, but isapparently higher in the south and east than elsewhere. Weather conditions right for the last week to lead to rapid spread of and multiplication of, BTV, a weather scenario that never really happened here last year.
The number of calves born in France so far this year is 20% lower than at the same time last year. If replicated worldwide that would have huge food security implications.
In Holland, the prevelance of BTV in cattle that were housed all year round was considerably lower than in cattle kept wholly ot partly outdoors.
The effectiveness of insecticides was variable. Better in cows than sheep, and better in sheep as a dip than as a spray. Problem in sheep was that the dip will not adhere to the midge feeding areas. At best a mitigation measure, not a cotrol measure. Keeping dung heaps away from cowshed doors, and grazing areas, was a bigger help in reducing the numbers of midges available to bite cattle.
Thanks To Intervet Schering Plough for organising a very useful update. The underlying theme might be “We know a lot more than we did, but not as much as we would like to”.
Further changes in policy and recommendations on various aspects of BTV control are inevitable.
Nick Clayton.
Vaccination Transmission Transplacental Eradication Current situation