WUR Expert Piet Van Rijn Advises: 'Apply A Second Bluetongue Vaccination To Sheep'

Bluetongue virus serotype 3 will spread further through Europe in 2024. The virus has been detected in the Netherlands, Germany and Belgium, but also in France and Denmark. Piet van Rijn, bluetongue and vaccine expert at Wageningen Bioveterinary Research, calls on livestock farmers to vaccinate their ruminants (cattle, sheep, goats and alpacas). “A second vaccination for sheep is recommended,” says Van Rijn.

Van Rijn was one of the speakers during a webinar organized by Royal GD. In his contribution, Van Rijn recalled the vaccination approach during the bluetongue epidemic of 2006-2008. “At that time, we were successful in eradicating the bluetongue virus serotype 8 by applying a targeted vaccination strategy.”

More aggressive
Northwestern Europe is currently dealing with serotype 3 of the bluetongue virus. In the Netherlands, with special permission from the Ministry of Agriculture (LVVN), three vaccines against serotype 3 have become available for use. These vaccines are produced according to the same process as the vaccines against BTV serotype 8.

The majority of Dutch sheep farmers have used one of these vaccines against serotype 3 as soon as they became available. Despite the vaccination, animals become ill as a result of infection with bluetongue virus serotype 3. According to Van Rijn, this finding is not unexpected. “Preliminary research into the effectiveness of the vaccines showed that the developed vaccines might be less protective than what was found in 2007-2008 with vaccines against serotype 8. “This is probably because bluetongue virus serotype 3 is much more aggressive than the serotype 8 we had to deal with in 2006-2008.”

Based on the current findings, Van Rijn advises to give sheep a second vaccination. “Our advice to sheep farmers is to give a second vaccination approximately four to five weeks after the first injection.” Van Rijn expects that this second vaccination will lead to better and long-lasting protection by stimulating the immune system again.

Cattle
“It is also important that cattle farmers apply the prescribed double vaccination,” Van Rijn emphasizes. “In general, cows get less sick from the bluetongue virus, but they are an important virus reservoir from which the midges can feed and spread the disease further.”

Perspective
With an effective and vigorous vaccination campaign, there is hope that the disease can be pushed back and the impact of bluetongue virus will decrease in the coming months. “As the midges remain active until late autumn, I do not expect the virus to disappear this year. We also need to be prepared for its re-emergence next summer. Vaccination is our only remedy to combat this aggressive variant of bluetongue virus,” says Van Rijn.