National veterinary associations are warning livestock farmers that a major Bluetongue virus (BTV8) threat still exists due to the extremely high numbers of animals being imported to Britain from the confluent Protection Zone in mainland Europe this year.

National veterinary associations are warning livestock farmers that a major bluetongue virus (BTV8) threat still exists due to the extremely high numbers of animals being imported to Britain from the confluent Protection Zone in mainland Europe this year.

Bluetongue threat still exists due to the high numbers of animal importsThe British Veterinary Association (BVA) and its specialist divisions the British Cattle Veterinary Association (BCVA), Sheep Veterinary Society (SVS) and Goat Veterinary Society (GVS) are calling on farmers to vaccinate and revaccinate their stock and to make a very careful risk assessment of the need to import animals.

The latest import figures from Animal Health reveal that in the first quarter of 2010 (Jan-Mar) nearly 5,000 animals were imported to Britain. This is more than in the whole of 2008 (4,000 animals imported) and, if this rate continues, we could see a 50% increase in imports on 2009 (13,000 animals imported).

The Bluetongue Experts Group (consisting of scientists from the Institute for Animal Health, Met Office, DEFRA vets and epidemiologists and representatives from the Devolved Administrations) has looked at the two main routes for disease to re-enter Britain, ie via wind-borne midge incursion from Continental Europe or via an animal movement into the country. Based on information regarding the disease situation in the EU and data on imported animals, the group concluded that importation is a greater risk than wind-borne spread not only for BTV8 but also for other strains, such as BTV1 that is still present on mainland Europe.

Bluetongue virus particleThe current situation in Britain is that there is no evidence of circulating disease of any BTV strain. Post-import tests have found no positive cases and the whole of Great Britain remains in a Protection Zone.

Vets are also warning that the infection could arrive through infected foetuses. Although all ruminants from the EU BTV8 Protection Zone are blood tested upon arrival, a small but significant number of pregnant animals could be carrying a BTV-infected foetus and still be negative to any blood test. The newborn animal could infect the local midge population and restart the circulation of the disease. Should that happen, Britain’s aim of achieving Low Risk or BTV-Free status would be set back for at least another year, prolonging the need for vaccination.

The BVA, BCVA, SVS and GVS are all reminding their members to encourage clients to continue vaccinating and to remain vigilant for any signs of the disease.

Nicky PaullNicky Paull, BVA past president and member of DEFRA’s Bluetongue Core Group, said: “Now is not the time to become complacent on bluetongue and it is essential to continue vaccinating against the disease. Previously the main threat to the UK was wind-borne midge incursion, but we are now being told by a panel of experts that import carries the greatest risk.

“We understand that farmers are desperate to replace culled TB reactors in cattle herds, but we would urge extreme caution when importing stock from areas where BTV8 has been circulating.”

Gareth Hateley, chair of the BCVA Exotic Disease Working Group, said: “Cattle that are up to date with vaccination from last year will only require one booster. If this is allowed to lapse then farmers will have to double vaccinate creating both cost and handling implications.”

Paul Roger, bluetongue stakeholder representative for the SVS, said: “Although only one dose of the vaccine is usually required for sheep we are concerned that if re-incursion occurs the lag in immunity means a risk of the disease breaking through. In an outbreak situation the scramble for vaccine could leave flocks exposed.”

Concluding, GVS honorary secretary Nick Clayton said: “We have all been concerned about imports from affected countries and people will need to make a careful assessment of the risk of importing strains of BTV into their herds.”

 

Original flag image ©iStockphoto.com/duncan1890
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