FREQUENTLY ASKED QUESTIONS
Bluetongue is a viral disease that affects ruminants, especially sheep and cattle. It can also affect goats, camels, deer and other wild ruminants. It has been named after one of the clinical signs that can occur in the affected animal, which is a bluish colouration of the tongue.
Sheep are particularly susceptible to more serious forms of the disease, whereas the infection is often causes fewer signs in other ruminants such as cattle and goats.
At present 24 types (serotypes) of the virus are recognised. The virulence of the different strains and the mortality rates of affected animals vary considerably.
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Does bluetongue present any threat to public health or food safety?
Bluetongue does not affect humans, nor is there any risk of the disease being contracted or spread through meat or milk.
The signs of bluetongue disease can be similar to those of other diseases so it is important that you notify your vet if you suspect bluetongue disease in order that a diagnosis can be made.
Sheep: The signs in sheep are very diverse. Some sheep become seriously ill and die, while others may exhibit hardly any signs at all. In most cases the first sign is high fever, followed by swelling and pain in and around the mouth, which in turn causes excessive salivation. Ulcers appear on the inside of the cheeks and the sides of the tongue; the oral tissue becomes a reddish-purple colour and the tongue can turn blue – hence the name bluetongue. Some sheep may develop swollen heads. Lameness, weight loss, breathing difficulties, and discharges from the nostrils and eyes are other possible signs. Mortality can exceed 25%.
Cattle: The signs in cattle are usually less severe than in sheep and in some cases animals may not show clinical signs of the disease. Signs may include discharges from the nostrils and eyes, profuse salivation and sores on the teats. Productivity and reproduction can be severely impacted.
Goats: The signs in goats are generally similar to those in cattle. Again, they may show no clinical signs of disease despite being infected with the virus.
Other ruminants: Camels, buffalos, deer and other wild ruminants can also become infected and they generally display only mild signs of the disease.
- Is bluetongue contagious?
Bluetongue is not contagious as ruminants cannot directly infect one another. It is transmitted by a very small insect (midge - Culicoides species), which passes the virus by biting uninfected animals after biting infected animals. In infected pregnant animals, infection can spread vertically to the embryo or foetus via the placenta.
- Where does the disease occur?
Various serotypes of bluetongue virus are present around the world. Since 2006, Northern Europe has been affected by serotype 8, which spread significantly in 2007. The disease restriction zone covers Austria, Belgium, the Czech Republic, Denmark, France, Germany, Luxemburg, the Netherlands, the United Kingdom and Switzerland..
- How can you prevent animals from becoming infected?
It has proven impossible to eradicate disease-carrying midges. The activity of these insects can be reduced by treating animals with an insecticide. Vaccination therefore has a very important role to prevent animals from being infected and to control the spread of the disease.
- Is it possible to vaccinate against bluetongue?
Yes. Several animal health companies have developed vaccines against various virus serotypes, including serotype 8.
EU legislation on bluetongue contains the option of carrying out a vaccination policy using live attenuated or inactivated vaccines. In late 2007, the European Commission announced their decision to co-fund new bluetongue vaccination campaigns in the zones identified in EU member states, given the rapid spread of the disease in Europe in 2007.
- Is it ever acceptable to not vaccinate?
No. Vaccination of all animals in Protection Zones is very important to prevent spread of the disease within your own herd and throughout the country. Also, it is not possible to predict the impact of the disease might have in your herd so failing to vaccinate is a huge risk.
You are only able to obtain vaccine if your farm is within a Protection Zone. Vaccine is only available through your veterinary surgeon.