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WUR-expert Piet van Rijn advices: ‘Give sheep second bluetongue vaccination’
The bluetongue virus serotype 3 is spreading further throughout Europe in 2024. The virus has now been identified in the Netherlands, Germany and Belgium, but also been detected in France and Denmark. Piet van Rijn, bluetongue and vaccine expert at Wageningen Bioveterinary Research, calls upon farmers to make sure their ruminants (cattle, sheep, goat and alpaca’s) are vaccinated.
Van Rijn spoke in a recently held webinar organised by the Dutch animal health organisation Royal GD. In his contribution to the webinar Van Rijn memorised the vaccination approach in the bluetongue epidemic of 2006 – 2008. “At the time we were successful in eradication of the virus by applying a vaccination strategy against bluetongue virus serotype 8.”
More aggressive
This time Northwest Europe is dealing with bluetongue virus serotype 3. In the Netherlands three vaccines against serotype 3 became available by special permission of the Ministry of Agriculture (LVVN). These vaccines are produced according to the same process for the BTV serotype 8 vaccines.
Most Dutch sheep farmers have applied one of these vaccines for serotype 3 as soon as these became available. Despite the vaccination, there are still quite a number of animals that become ill as a result of infection by bluetongue virus serotype 3. Indeed, preliminary experimental results showed that the vaccines are less protective, likely because the serotype 3 bluetongue virus is much more aggressive than the bluetongue virus serotype 8 in 2006-2008. “Our advice to sheep farmers is to apply a second vaccination around four to five weeks after the first shot.” Van Rijn expects this second vaccination will lead to better and lasting protection by triggering the immune system again.
Cattle
“It is also important that cattle farmers apply the prescribed double vaccination. In general cows become less sick from bluetongue, but they are an important virus reservoir from which the midges can feed and further spread the disease.”
Perspective
With an effective and rigid vaccination campaign there is hope that the disease can be downplayed and the impact of bluetongue will decrease in the months to come. “As the midges will remain active until late autumn, I don’t expect the virus to disappear this year and we should be prepared for its re-emergence next summer. Vaccination is our only remedy to combat this aggressive variant of bluetongue virus”, according to Van Rijn.