In autumn 2011 the first evidence of a new virus infection of cattle, sheep and goats was found in Germany and Holland. This virus was called after the location of its first identification, hence Schmallenberg Virus (SBV). It has since been shown to be spread by midges. The infection is relatively mild in most animals but if it occurs during the critical first stage of pregnancy, then the resulting calf, lamb or kid can be deformed.
Testing of deformed calves and lambs born this spring in England, Wales and Scotland showed that SBV only affected flocks and herds in the South and East of England at that time. It was hoped that the virus may not overwinter in the UK, but there is now evidence that the virus is spreading again this summer. Therefore it is possible that the virus may spread to new areas. While much more needs to be learnt about SBV, as infection with the virus during early pregnancy can cause deformed calves, lambs or kids, delaying mating to periods of the year when there is less midge activity is expected to reduce the risk of disease.
Post movement testing
Livestock keepers in unaffected areas of Great Britain are advised to consider with their veterinary surgeons whether testing introduced breeding stock for evidence of SBV antibody might be advisable. Positive results could suggest a risk of the introduction of SBV to a flock or herd. In that situation further testing of in-contact animals to show whether the disease has spread in the unit is recommended. If the virus is active on the unit then delaying mating until a high proportion of the flock or herd are immune may be advisable.
The cost of testing is £6.20 (+VAT) per animal or £5.00 (+VAT) per sample for batches of 10 or more. In addition there is a charge by your veterinary surgeon for collecting the samples.
Ideally farmers would arrange with their vet to test purchased stock on arrival and re-test in 14-21 days (re-test regardless of the initial test result). The results of these tests would give information about whether any exposure was recent and therefore potentially active, or historical and probably inactive.
Most farmers will want to test purchased stock shortly after arrival. We recommend delaying for between 14 and 21 days. Then if imported animals are positive, consider testing a cohort of the remainder of the flock 14 – 21 days later. If imported animals test negative, animals are almost certainly not exposed and there is no need to test the flock.
For further information, please contact Brian Hosie via the details below or Kim Willoughby (Moredun Institute) on 0131 445 5111.