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Bluetongue virus (BTV) is an infectious, non-contagious, vector-borne viral disease. It affects wild and domestic ruminants such as sheep, goats, cattle, deer and camelids. It does not infect humans and there is no risk to public health or food safety.

First published:
16 November 2018
Last updated:

Latest information

Welsh keepers are encouraged to source stock responsibly

Huw Irranca-Davies MS, Deputy First Minister with responsibility for Rural Affairs encourages farmers to source stock responsibly and remain vigilant to the signs of disease following the first case of Bluetongue virus serotype 3 (BTV-3) in Wales. 

For the latest updates on the Bluetongue situation in England, please visit gov.ukFurther information and resources on the current bluetongue situation are available on the Ruminant Health and Welfare website.

Suspicion and confirmation

Contact your local Animal and Plant Health Agency (APHA) office immediately on 0300 303 8268 if you suspect Bluetongue.

APHA vets will investigate suspected cases.

Clinical signs

The following clinical signs may be present in sheep:

  • ulcers or sores in the mouth and nose
  • discharge from the eyes or nose and drooling from the mouth
  • swelling of the lips, tongue, head, neck and coronary band (where the skin of the leg meets the horn of the foot)

Other clinical signs include:

  • red skin as a result of blood collecting beneath the surface
  • fever
  • lameness
  • breathing problems
  • abortion
  • death

The following clinical signs may be present in cattle:

  • lethargy
  • crusty erosions around the nostrils and muzzle
  • redness of the mouth, eyes and nose
  • reddening of the skin above the hoof
  • nasal discharge
  • reddening and erosions on the teats
  • fatigue
  • fever
  • reduced milk yield
  • loss of appetite
  • abortion

Adult cattle may serve as a source of virus for several weeks while displaying little or no clinical signs of disease. They are often the preferred host for insect vectors.

Photos showing the clinical signs of bluetongue are available (on flickr).

Bluetongue in calves

Bluetongue can be transmitted to a foetus from an infected pregnant animal. This can lead to abortion, calves being born small, weak, deformed or blind, and death of calves within a few days of birth.

Livestock keepers and vets should consider bluetongue as a possible cause for calves showing these signs.

Transmission

Bluetongue virus can be spread by certain species of biting midges (Culicoides species). Many of which can be found throughout Great Britain.

Midges are infected with the virus when they bite an infected animal. The virus spreads when the infected midge then bites an uninfected susceptible animal. Once a midge has picked up the bluetongue virus it will be a carrier for the rest of its life.

Midges are most active between April and November. The weather (temperature, wind speed and direction, and rain) affects how quickly and how far midges can spread the disease.

Bluetongue virus can also be spread through the movement of infected animals, and through biological products such as:

  • blood
  • germinal products (semen, ova or embryos)

including by imports from countries where Bluetongue may be circulating undetected.

There is evidence dogs and other carnivores can become infected with bluetongue virus after ingesting infected material such as aborted material or afterbirth.

However, this is a rare occurrence. Bluetongue is principally a disease which affects ruminant animals such as:

  • sheep
  • cattle
  • goats 
  • deer

and camelids such as:

  • llamas 
  • alpacas

It is spread by midges. It does not affect people or food safety.

Prevent your pets from eating, chewing on or playing with potentially infective material. For example: aborted material, afterbirth.

When you walk your dog, follow the Countryside Code (on gov.uk) and Marine Codes of Conduct (on wildseas.wales).

Contact your vet if you have concerns about the health and welfare of your pet.

Prevention and control

You can help to prevent Bluetongue virus from spreading by:

  • responsibly sourcing livestock
  • remaining vigilant to signs of disease 
  • maintaining good hygiene and biosecurity on your premises
  • housing animals in buildings that keep out biting midges – this is especially important at dawn and dusk
  • not allowing farm dogs, cats or pets to eat, chew on or play with potentially infected materials (such as aborted material and afterbirth)

Vaccinating your animals

There is no vaccine currently licensed for use in Wales for bluetongue virus serotype 3 (BTV-3). This is the serotype confirmed in England in November 2023.  

Make sure your animals can be traced

If you keep animals as livestock or pets, you must follow rules to make sure they can be traced. This includes registering your land and animals.

Read the rules for keeping cattle, sheep, goats and deer. 

Contact the Animal and Plant Health Agency (APHA) if you keep camelids (such as llamas or alpacas) or you’re unsure about the rules.

Check if you need to apply for a specific movement licence (on gov.uk) to move animals onto or off a bluetongue restricted premises.

Keepers considering importing animals or biological products from BTV affected or potentially affected countries should consult their vet about the risks associated with these activities. This should be done before deciding to import. Imported animals that test positive for Bluetongue may be culled or be returned to the country of origin. Further information on import requirements is available (on gov.uk).