The likelihood of the Schmallenberg virus (SBV) circulating in the north-east has increased after a fourth case was confirmed in a dairy cow.
It aborted a calf and then tested antibody positive for the virus, which has wreaked havoc across Europe since it was first discovered in livestock near the German town that gave it its name two years ago.
Catriona Ritchie, a vet at SAC Consulting’s veterinary surveillance centre at Craibstone, Aberdeen, said the latest case was north of Aberdeen on a farm six miles away from one of the three previous incidents, all of which involved suckler cows and their calves born deformed.
The confirmed cases are north-west of the city and within 20 miles of it.
Miss Ritchie said it was not known when the home-bred dairy cow was infected, or if it was the virus that caused the abortion as vets did not examine the calf.
SBV has no impact on human health. However, it causes fever, milk drop and diarrhoea in adult cattle, sheep and goats.
It also causes late abortion and birth defects in newborn cattle, sheep and goats if dams are bitten by virus-carrying midges and infected at a certain stage of pregnancy.
The virus is thought to have been taken to the north-east late last year. There was a link between the first case detected and cattle moved to the area from Dumfries-shire last autumn.
All the subsequent cases have no direct link with the initial incident, raising the prospect that the virus has or is circulating in the midge population.
Miss Ritchie said tests on 10 other cattle on the first farm infected failed to detect any signs of antibodies, indicating that any infection level is low.
That is in stark contrast to the situation on the Continent, where flocks and herds have been found to have infection levels of between 80-90%.
Miss Ritchie said farmers contemplating vaccinating their herds and flocks against SBV should be speaking to their vet.
Sheep need one dose of vaccine.
Cattle require two, but there needs to be a four-week gap between the first and second doses.
The vaccine cannot be given to pregnant animals.
She added: “The opportunity for vaccinating spring-calving cows has been missed, but it is something farmers might want to consider for next year.”
Many pedigree breeders, particularly those with sheep, have already vaccinated their flocks as SBV is known to have caused considerable losses in England earlier this year before the vaccine became available.
A second SBV vaccine is likely to become available in the UK soon. Merial has received approval for its inactivated vaccine in France.
Approval has been sought in the UK from the Veterinary Medicines Directorate (VMD) for the same product, and that is expected to be granted in the coming weeks.
A Merial spokeswoman said: “The vaccine is also under review in the UK by VMD.
“The official indication and availability of doses will be communicated when the provisional licence is granted.”
SBV, a non-notifiable disease, has been officially recorded on more than 8,000 farms Europe-wide, but the likelihood is that thousands more have also suffered from it.
Farmers have again been reminded to report any suspicious abortion or animal born with defects to their vet.