The Bluetongue Virus

04 July 2016

Article by Edward Armstrong, National Assembly for Wales Research Service

Darllenwch yr erthygl yma yn Gymraeg | View this post in Welsh

image of a sheep

Image from Flikr by David Martyn Hunt. Licensed under the Creative Commons

A recent outbreak of the Bluetongue virus in France has prompted a warning about the potential spread across the UK. What is Bluetongue and how could it effect farmers in Wales?

What is bluetongue?

Bluetongue is a disease caused by a virus that can affect all types of ruminant animals including sheep, cattle, deer, goats and camelids. It has no effect on horses and pigs and does not pose a health risk to humans.

The virus is spread by certain types of biting midges. These are most prevalent between the spring and summer months of May and October, heightening the risk of the disease spreading during this period. The disease cannot be transmitted between animals, although transmissions via mechanical or unhygienic practices can occur.

A detailed overview (PDF, 40KB) of Bluetongue has been compiled by the Department for Environment, Food and Rural Affairs (DEFRA), the devolved administrations and the farming industry.

What is the current risk?

In February 2016 DEFRA published (PDF 863KB) a comprehensive qualitative risk assessment evaluating the spread of Bluetongue in the UK.

The current Bluetongue risk follows a recent outbreak in France. As of 13th May 2016 (PDF 187KB) there have been 272 cases in France, all but one within cattle holdings. The majority of recorded outbreaks have been in central France and as yet have not spread towards the north coast.

Due to strict controls on the animal trade, the introduction of the disease to the UK would most likely be via infected midges. Modelling work (PDF 863KB) carried out by DEFRA has assessed the spread of the disease, emphasising that it is dependent on the level and escalation on the continent and the climatic conditions.

It concludes, albeit with a high level of uncertainty, that the risk of incursion by the end of the summer is 60–80%. It stresses that this is highly reliant on the ability of the French authorities to control the disease, and the temperatures across the UK.

What are the symptoms?

Although the disease more frequently impacts cattle, it affects sheep more severely. Clinical signs of the disease include facial swelling, typically the lips and tongue, lethargy, discharge from the nose and mouth, respiratory problems and increased temperature.

A detailed overview of the symptoms are provided by the Joint Campaign Against Bluetongue (JAB) (PDF 129KB) and DEFRA (PDF 132KB).

Past outbreaks in Wales and the UK

The last major outbreak of Bluetongue in England and Wales occurred between 2007 and 2008. A Bluetongue protection zone was enforced in order to try and control the spread of the disease by restricting the movement of livestock and encouraging vaccination.

Wales and the rest of the UK achieved Bluetongue free status in 2011. This again permitted the free movement of unvaccinated livestock between Wales and other countries free from the disease.

DEFRA has published a Bluetongue Disease Control Strategy (PDF 234KB) which provides a detailed outline of the measures that would be considered following a suspected or confirmed outbreak in the UK.

What can you do?

Vaccinating ruminant animals against the disease is an effective measure to reduce the risk of infection.

NFU Cymru has advised farmers to speak to their vets to discuss the risk and options available to them, and have called on manufactures and vets to provide clear information on vaccine availability and pricing.

From mid-July 2016 onwards it was announced that the BLUEVAC BTV8 Bluetongue vaccine will be available throughout Great Britain manufactured by MSD Health.

The JAB leaflet (PDF 129KB) highlights other ways in which farmers can take action, these include;

  • Monitoring stock and reporting signs of disease;
  • Responsibly sourcing animals; and
  • Upholding high levels of biosecurity.
  • Suspect animals must be immediately reported to the Animal and Plant and Health Agency (APHA) who will investigate, failure to do so is a criminal offence.