Import surge’s Bluetongue virus threat

The National Disease Control Centre is a state body of major importance to Irish farmers.

Import surge’s Bluetongue virus threat

The National Disease Control Centre is a state body of major importance to Irish farmers.

Every now and then we, as veterinary practitioners, receive communications from this section of the Department of Agriculture, Food and Marine, alerting us to be vigilant for some exotic disease that may be making its way towards our nation. The latest such warning asks us to be on the lookout for Bluetongue disease caused by the Bluetongue virus (BTV).

What is very interesting, and also very worrying, is the information about the number of animals imported.

In July and August of 2018, the number of cattle imported from mainland Europe was 36.

This year, in July alone, the number went up to 135. This phenomenal increase it is making the National Disease Control Centre very nervous of a disease such as Bluetongue being introduced into our national herd. Since the abolition of quarantine regulations 35 years ago, we have seen the introduction of many new diseases to Ireland, like Mycoplasma, Schmallenberg, IBR, etc.

We do not need or want to bring in another one.

The Bluetongue virus was first noticed in the 19th century in South Africa, and since then it has been spreading. The way it spreads is similar to how Schmallenberg spreads — by midges biting infected animals and then biting further animals and infecting them.

The disease reached North Africa by the 1940s. Apart from one or two outbreaks in Spain and Portugal, this disease was considered not to exist in Europe, until 1998. Since then, we have seen a lot of outbreaks in other Mediterranean countries. More recently, it made dramatic incursions into the likes of Nederlands, Belgium, Luxembourg and Germany.

So are we to be next?

The most likely way that it will be brought in to Ireland is by importing an animal carrying the disease. Other less likely avenues include infected midges blown across the sea to Ireland; through importation of infected semen; etc.

Let’s look at a scenario where a bunch of cattle have been blood-tested for BTV and await transportation from mainland Europe to Ireland.

The blood results may come back negative, but what is there to stop these animals being bitten by infective midges while they await transportation, resulting in some of these animals coming into Ireland with the infection, but not yet showing signs of the disease.

Innocently they proceed to their host farm in Ireland where they are bitten by the Irish midge, and the transmission process begins here.

Whatever about being able to test animals for Bluetongue, there is no way we can test the midge population or control them once this disease gets in among them. In Ireland, the midge season stretches from April to November. We are in the middle of it now, that is why the National Disease Control Centre is alarmed by the increase in imports.

If an animal here is found to be infected with Bluetongue virus, severe movement restrictions will be put in place in zones of 50km, 100km and 150 km around the affected farm.

Animals will be housed, and those that are affected or suspected will be destroyed.

So what clinical signs are we looking out for?

Ulcers and crusts on the lips, muzzle, mouth or teats, with drooling and a drop in milk yield or weight, and possibly lameness, are the signs to look out for.

The disease can affect cattle, sheep, deer and other ruminants.

Importation can have a lot of consequences!

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