Two outbreaks of a new sheep disease have been confirmed in Norfolk flocks, officials have confirmed today.

The virus, which causes abortion in ewes, has also been identified by the Animal Health and Veterinary Laboratories Agency.

A further case has been identified on a Suffolk farm and another in East Sussex in sheep.

The Bury St Edmunds veterinary centre was alerted by a Norfolk vet, who sent samples for immediate analysis. The flocks are thought to be in North Norfolk.

Schmallenberg virus (SBV) was only officially identified in November last year in northern Europe as a new virus following a number of disease outbreaks in herds of cattle in Germany, where clinical signs included reduced milk yields.

This virus appears to be spread by insects, mainly midges and mosquitoes, although the precise means of transmission to animals has not been scientifically proven.

The risk of human health is regarded to be very low but farmers and veterinary surgeons are advised to take all sensible bio-security precautions. SBV is not a notifiable disease but farmers have been urged to report any unusual signs to their veterinary surgeon.

In recent weeks, there have been a number of reported outbreaks in sheep in Dutch flocks, where stillbirths and miscarriages have been found.

The SBV disease, which is thought to infect ruminants. As a result, cattle, sheep and goats may be at risk from infection.

Although this virus is thought to be spread by midges, it is quite different from BTV or blue tongue virus. BTV was also spread by the culicoides midges which also infected large numbers of mainly sheep and cattle in the eastern counties of England.

Mid-Norfolk farmer Roger Long, who is a member of the National Farmers' Union's regional livestock board, had been informed earlier today. 'We don't known how it has been caused. We don't know the extent of the infection,' he added.