Originally from: Farmtalking
                        
Sheep face 'invading' tropical virus

Tim Radford
Wednesday September 10, 2003
The Guardian

Hard on the heels of the foot and mouth epidemic, a deadly new menace could be putting Britain's 40 million sheep at risk. Bluetongue virus, spread by a tropical midge, has already crossed the Mediterranean and is being passed "like a baton in a relay race" from one set of midge hosts to another, experts claim.

"It appears to have expanded its range northward and westward into areas where it has never been found before," Philip Mellor, of the Institute for Animal Health, told the British Association festival of science in Salford yesterday. "If you hadn't been hearing about foot and mouth virus in the UK in 2000 and 2001, you would have been hearing about bluetongue virus."

The virus carrier is a north African and Middle Eastern midge known as Cullicoides imicola, a relative of the garden midge found in Britain. The virus replicates in the cells lining the smaller blood vessels of animals. "It makes those blood vessels leaky and fragile – particularly in areas like the mouth, eyes and feet." The consequence is oedema.

"You also get haemhorrage," Dr Mellor said. "There will be an escape of blood into the mouth [and] conjunctivitis so secondary infections in and around the eyes. There will be damage to its hooves. "Sheep that cannot walk very well, see very well or eat very well, die very well."

He said the virus could also paralyse smooth muscle which could cause the sheep to suffer inhalation pneumonia.

The virus has been identified more than 500 miles north of its traditional range and observers say a temperature rise of 2–5C could bring the infection to Britain.

· British chicken farmers may be at risk from a lethal form of avian flu virus, warned Dennis Alexander, of the veterinary laboratories agency. He said there was a huge reservoir of avian influenza in wild birds and that some of the genes of the viruses were shared with those causing human flu.

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