Chief vet warns of bluetongue outbreak

Mar 24 2008 Steve Dube,

THE devastating livestock virus bluetongue could wreak havoc in coming months, after surviving the winter in a hidden reservoir of animals.

Wales chief vet Christianne Glossop said only 60 cases of the often fatal disease had been confirmed by the time the vector-free period – when the midges that carry the virus are inactive – began on December 23.

But since then pre-movement testing of livestock in the restriction zones thrown up around confirmed outbreaks, has discovered other animals testing positive for the disease. Two new cases were discovered just before Easter, bringing the number of farms under quarantine up to 103.

“That’s a worry because it means that we probably have other infected animals out there that have not yet been discovered,” said Dr Glossop.

“What is going to happen when the spring arrives?

“We know from other parts of the world that cattle, unlike sheep, don’t always show dramatic clinical signs of bluetongue.

“The critical time for this complicated and terrible disease is coming up as the weather warms up and the midge population becomes more active and the virus could start spreading more effectively.

“Will we have the kind of epidemic that northern Europe saw last summer, or will we be fortunate enough not to see that this year? Nobody has the answer to that.”

Last year the disease spread from a handful of cases in August 2006 to thousands across Holland, Belgium, Luxembourg, Germany and northern France.

The costs in animal deaths were enormous – around euro100 million in Holland, euro40 million in Belgium and euro3.3 million in northern France – and there is no compensation for affected farmers.

“A lot of people think the actual costs are much higher because the figures don’t take account of loss of productivity in animals that survive,” said National Sheep Association chief executive Peter Morris.

“And in some ways this disease is worse than foot-and-mouth because there are trillions of midges and each one can infect an animal with a single bite – and there is no compensation when your livestock fall sick.

“So far we have bottled up the disease in the eastern quarter of the country, but being realistic the odds are that the disease will beat us and, when that happens, I don’t know what the answer is.”

No one knows how the particular strain of virus – serotype 8 – leapfrogged from Africa over other strains in southern Europe to infect the north of the continent in 2006.

Meteorologists say it reached Britain when infected midges were carried by warm easterly winds across the sea from Belgium or the Netherlands to East Anglia overnight between August 4 and 5 last year.

A total of 1,600,000 farm animals are now within the protection zones thrown up on a 12.4-mile radius of the 60 cases that emerged since the first was diagnosed on September 22.

Pre-movement testing from these zones and the wider surveillance zones, together with discoveries of the virus in some imported animals, means that a total of 101 premises are under restrictions.

They include a single one in Wales, at Capel Dewi, Llandysul, where a Texel sheep imported from Holland was slaughtered after testing positive.

The case was a mystery as the animal had also been tested in Holland and quarantined for two weeks before being transported to the farm, on the borders of Carmarthenshire and Ceredigion, in February.

Experts are also baffled by the beef animal that returned a positive result in pre-movement testing in Poole, Dorset, a few days earlier.

That incident extended a restriction zone into Wales for the first time, and all livestock in Monmouthshire and southern Powys south of the A40 must now be tested before being moved outside the zone.

If the disease resurfaces in May or June this year, the fight to control it will enter a new phase. Defra has ordered 22.5 million doses of vaccine, of which 2.5 million have been bought by the Welsh Assembly Government – enough to treat between 70% and 80% of susceptible animals in the Powys and Monmouthshire restriction zone.

EU rules restrict the use of the vaccine to animals within immediate protection zones, so no farms in Wales are eligible.

If the disease does spread this summer and voluntary vaccination becomes an option in Wales, the treatment will be available on prescription from vet practices.

Farmers will probably have to pay something like 70p for each shot.

Cattle will need two injections, and the treatment will have to be repeated the following year.