Bluetongue is an exotic animal disease, found in many European countries, which represents a serious threat to Irish livestock if it were to occur here.
Bluetongue disease is caused by a virus which has many serotypes, 11 of which have been reported to date in Europe.
The bluetongue virus (BTV) can affect all types of ruminant animals, including cattle, sheep, goats, and deer, and camelids such as llamas and alpacas.
The disease does not affect humans or pose any food safety concerns.
Bluetongue is primarily spread from animal to animal by midges that feed off the blood of an infected animal and then spread the virus to subsequent animals they bite.
The Culicoides species of midges that are capable of spreading the virus are found in many European countries, including Ireland, and wind dispersal of infected midges can spread the disease.
As infected midges could also enter the country in animal transport vehicles, transport vehicles must have an insecticide applied before moving susceptible animals from bluetongue-restricted regions.
There is evidence to show that the virus can be spread through biological products such as blood, or germinal products such as semen or embryos. Infected pregnant animals can potentially pass the virus on to their offspring in the womb, making these animals a particularly high-risk group for introducing the virus to Ireland.
Sheep are most likely to display clinical signs of bluetongue. Infected cattle and goats tend to show less clinical signs and sometimes can be asymptomatic.
Such infected animals that do not show obvious disease are problematic because they can act as hidden carriers of the virus to be spread to other animals.
Clinical signs can vary from animal to animal but could include any or all of the following: swelling of the head, respiratory distress, drooling, reddening of tissue surrounding the eyes, sores and crusts on the face, mouth and teats, discharge from the eyes and nose, loss of appetite, drop in milk yield and abortion.
It has been shown in previously unaffected countries that mortality rates during an initial outbreak can be as high as 70% in affected sheep.
How can we keep bluetongue virus out of Ireland?
The importation of an asymptomatic infected animal represents the most significant risk factor for the introduction of the disease into Ireland.
Animals that originate from bluetongue-affected countries are vaccinated against the disease. However, no vaccine is 100% effective for all animals and there are a number of mitigating actions that can be taken to prevent an outbreak of bluetongue in Ireland.
Before importing animals that are susceptible to bluetongue disease from Europe, you should ask yourself the following questions:
1 Is import of these animals really necessary?
It may be possible for the genetic change or gain that you are looking for to be obtained locally or in a bluetongue-free country. If the import is necessary, then every effort should be made to only import susceptible animals during the low-risk season for midge activity (November to March).
If an outbreak of bluetongue were to occur in Ireland during the midge season, control and eradication of the disease could be difficult in the short term.
2 Are these animals pregnant?
Remember, infected pregnant animals can potentially pass the virus on to their unborn offspring in the womb which may not be detected until the offspring is born so pregnant animals pose an even higher risk than non-pregnant animals of inadvertently introducing BTV into the country. If the import is necessary, consider breeding the animal in Ireland post-importation.
3 Am I buying these animals from a reputable source?
Consult with your private veterinary practitioner before purchasing animals in other countries for advice on pre-import tests to prevent the introduction of a disease into your herd, flock or the country.
Obtain proof of vaccination and request any pre-export test results for any relevant diseases such as bluetongue before you import. A pre-export PCR test could be requested by the importing farmer as an additional precautionary measure.
Contact your local regional veterinary office (RVO) for advice on importation certification requirements and ensure that you have adequate facilities on the farm to isolate and house the animals once they arrive.
4 What can I do if I import animals once they arrive in Ireland?
Isolate the animals indoors in a clean shed away from the rest of the herd or flock.
Check that the animals have the correct identification and certification requirements.
Ensure that they have access to clean, dry bedding, feed and water and contact your vet without delay if any animals appear unwell.
Contact your local RVO immediately once the animals arrive to arrange for the required post-import checks for diseases including bluetongue.
Early detection of the bluetongue virus is of key importance to controlling any potential outbreak.
Bluetongue is a notifiable disease, meaning there is a legal obligation for any suspect case to be reported to the Department of Agriculture. If you suspect the presence of bluetongue on your holding, contact your local RVO without delay (during office hours) or the National Disease Emergency Hotline on 1850 200 456 outside of office hours. The Department has a dedicated page on bluetongue: www.gov.ie/bluetongue.
An outbreak of bluetongue in Ireland would result in disease control zones of 150km radius being introduced, with movement and export restrictions applied to animals originating from within these zones. The loss of our bluetongue-free status could also affect our ability to trade with countries outside of the EU.
Mandatory vaccination of animals against bluetongue, which is not carried out in Ireland at present, may need to be introduced during an outbreak. Therefore, it is extremely important that anyone who intends to import animals that are susceptible to bluetongue considers and implements all preventative measures that they can to help keep Ireland free of bluetongue.