What is it?

Bluetongue Virus (BTV) infects ruminants and camelids, and is primarily transmitted by biting Culicoides midges. Midges biting an infected, viraemic animal ingest BTV with their blood meal, and after 4 to 20 days (depending on temperature) can pass the virus onto the next animal(s) they feed on. The involvement of biting midges and the requirement for temperatures to be high enough for the virus to become infectious inside the midges results in BTV’s seasonal pattern. As midges become active (April to November) the risk of BTV-infected midges being blown across to the UK from Europe and thus BTV entering and circulating in the UK increases.


Why does it matter?

As of 7th May 2024 the Animal and Plant Health Agency (APHA) have confirmed a very high probability of a new introduction of Bluetongue Virus serotype 3 (BTV-3) into Great Britain. As such, awareness of signs of the disease is increasingly important. BTV does not pose a threat to human health or food safety, but can have significant impacts on animal welfare and production. Signs and severity of the disease are highly variable depending on the BTV serotype, the species and breed infected and also between individuals.


What should we look out for?

As in sheep, BTV in camelids has a highly variable presentation; some individuals infected with BTV-3 have shown mild signs only and gone on to recover, but sadly some have showed a rapid deterioration, with breathing difficulties resulting in either death or euthanasia. Vets and owners are advised to be vigilant for the same signs as seen in other species. These include:

  • fever
  • reduced appetite
  • lethargy and depression
  • reddening of the eyes, nostrils and mouth
  • swelling of the face and lips
  • clear and stringy (not frothy) salivation
  • breathing difficulties
  • stiff or uncomfortable gait, lameness
  • swelling around the coronary band (so toes in camelids)
  • reduced fertility, abortions, weak or disfigured calves or lambs (therefore cria)
  • decreased production (weight loss, wool (therefore fibre) breakage)

It is important to note that animals can be infected with BTV and not show these signs.

What should we do?

Unfortunately vaccines (which would offer the best protection against BTV) are currently unavailable. Vaccines that were used against BTV-8 in the 2021 outbreak would not offer any cross-protection against the BTV-3 currently circulating in Europe. Attempts to control midges and prevent them from contacting livestock and thus infect them with BTV (removing dung, applying insect repellents, insecticides and stabling animals) are also unlikely to be effective. This means that our focus is advised to be vigilance to allow prompt detection of disease and where appropriate symptomatic and supportive treatment for affected animals. Any owner concerned about one of their animals should contact their vet, and if BTV is suspected APHA must be contacted immediately. Call 03000 200 301 in England, 03003 038 268 in Wales, or your local field services office in Scotland.


For more information:


Bluetongue: how to spot and report it