Calls for vaccination against bluetongue disease

A vaccine is available for the deadly animal virus that has been rampaging across northern Europe, and was reported for the first time in the UK last week. On Wednesday, agriculture ministers from the Netherlands, Belgium, France and Germany will ask the EU to approve widespread vaccination. But to stop a bigger outbreak next year, animals must be vaccinated in spring before infected, biting flies which spread the disease start swarming. And the vaccine may not be ready, because the plant in the UK that makes it has been shut following safety concerns. Bluetongue is common in livestock in warm countries, and is carried by tiny biting midges of the genus Culicoides. Symptoms are often mild in cattle, but it can kill up to 80% of infected sheep. Cold winters previously kept the disease out of temperate countries by killing off any infected midges.

As climate has warmed, however, bluetongue has spread into countries such as Spain and Italy. In July 2006, it broke out for the first time in the Netherlands, and quickly spread to Belgium, Germany, France and Luxembourg.In August 2007, it hit those countries again, showing the infection can now persist through Europe’s winters. It has also spread – this year has seen nearly 5000 outbreaks. With infected animals near the Belgian coast experts predicted that infected midges, which can be blown 300 kilometres and carried in vehicles, would reach the UK. Two cows with bluetongue have now been confirmed on a farm near Ipswich, UK, since 22 September. Because of previous outbreaks in southern Europe, the French-owned vaccine manufacturer Merial started developing vaccines three years ago, with initial money from the European Commission. Spanish and Italian farmers have been using them successfully for several years, says Philip Connolly, a Merial spokesman.

There are 24 immunologically distinct “serotypes” of bluetongue virus – vaccine against one does not work against another. European farmers vaccinate against serotypes 2 and 4. The UK and northern Europe have been hit by serotype 8, apparently from Sub-Saharan Africa. But there is a vaccine to that too. “We decided last January to start serotype 8 vaccine development,” says Connolly. “The vaccines to 2 and 4 work well, so we are confident this will be just as effective.” He likens the switch in serotype to the changes in each year’s flu vaccine, which do not require separate testing. “We had every intention of having the vaccine ready for early 2008,” Connolly told New Scientist. “But our factory isn’t allowed to touch live virus.” The vaccine is made from killed bluetongue virus. The plant at Pirbright where Merial manufactures it was implicated in an escape of foot and mouth disease virus in August, and the plant has shut down all work with live viruses since. “We would have to be back up and running by late October to do it in time,” says Connolly. Another vaccine company, Intervet, has developed a serotype 8 vaccine, but will not have an approved plant in time.

New Scientist
October 2, 2007

Original web page at New Scientist