16 Oct 2023
Hundreds of farms in the Netherlands are understood to have been affected by the BTV-3 strain, with a further incident also being reported in Belgium.
Allister Webb
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Image: © Viktor Kunz / Adobe Stock
Vets and farmers are being urged to be “extremely vigilant” following reports that a new form of the bluetongue virus is spreading rapidly in parts of Europe.
Hundreds of farms in the Netherlands are understood to have been affected by the BTV-3 strain, with a further incident also being reported in Belgium.
Although no cases have been detected in the UK so far, industry group Ruminant Health and Welfare (RH&W) has been holding emergency meetings with stakeholders about the disease, which is formally classed as notifiable.
The organisation is advising farmers and vets to beware when buying in animals, and take action to report any signs, as well as remaining vigilant.
Several veterinary bodies, including the BVA and BCVA, as well as the veterinary societies for both goats and sheep, are part of the organisation and there is concern that the new strain could pose a greater threat than other forms of the disease.
Keith Cutler, an RCVS-recognised specialist in cattle health and production with Synergy Farm Health, said that while previous vaccination campaigns against BTV-8 had been “very successful”, there would be little cross-protection against the new strain.
Sheep Veterinary Society president Joseph Henry, who is a member of the RH&W steering group, said that would make any potential outbreak “difficult to control”. He added: “It’s so important that we follow the advice to take action and prioritise good biosecurity measures while remaining extremely vigilant to the disease at this stage.”
The BCVA has also updated its members on the situation ahead of its annual congress, which takes place in Telford this week.
As of 11 October, around 1,000 Dutch farms were estimated to have been affected by the current outbreak, which was first reported in early September.
Some reports have suggested the BTV-3 strain may have originated in central Africa, although Defra officials described those claims as “speculation” as they stressed the source is still unknown. The strain is said to be closely related to a form of the virus detected in southern Italy five years ago, though work by the Dutch authorities to sequence it is continuing.
But the latest Defra assessment of the situation, dated 29 September, described the overall risk of BTV entry into Great Britain as medium, based on both the Dutch outbreak and recently reported cases of the BTV-8 strain in southern France.
However, it also acknowledged that the BTV-3 strain poses a “greater concern” because of the lack of available vaccine options.
The document said wind-borne incursion of midges from affected areas posed the greatest risk of the disease being brought into Britain, but also recognised the potential threat from illegal importations.
Mainland France has been declared as a BTV restriction zone, meaning susceptible animals cannot be moved into Britain without prior vaccination, while the report said trade in live sheep and cattle from the Netherlands “is now no longer possible”.
It added: “Livestock owners are strongly advised to source replacement stock responsibly and consult with their private veterinarians to put in place controls preventing the introduction of bluetongue virus.”
A Defra spokesperson told Vet Times that, while the UK is officially bluetongue-free, the department was “not complacent” about the threat the disease poses.
He said: “The detections in Europe are an important reminder to all farmers to be vigilant in sourcing their stock and germinal products, ensuring imported animals are properly vaccinated and that they have strong biosecurity practices in place to prevent the spread of disease.
“If farmers have any suspicions of disease, they should report them to APHA immediately.”
The threat posed by infected midges is being seen as a particular concern following the recent spell of unseasonably warm weather.
Clinical signs of the virus can include drooling, mouth lesions, high fever, lameness, swollen heads and sudden death in sheep, plus teat, eye, coronary band and nose lesions in cattle.
NFU chief animal health and welfare advisor Cat McLaughlin said: “BTV-3 appears to mimic BTV-8 in its behaviour, leading us to be extremely cautious to the risk it poses. We must adhere to advice and do all we can to keep it out.”
The National Sheep Association’s chief executive, Phil Stocker, added: “We’d strongly advise farmers to beware when buying livestock from Europe, and to request pre-movement testing of animals prior to departure.
“All imports of live animals are subject to post-import testing with restricted movements until a negative post-import test result has been confirmed, so caution is key.”
