A new animal disease which causes birth defects and miscarriages in livestock has now been found on 74 farms in England.

The Schmallenberg virus first emerged in the Netherlands and Germany last year, causing mild to moderate symptoms in adult cattle, including reduced milk yield and diarrhoea, and late abortions and birth deformities in newborn sheep, goats and cattle.

It is thought the virus is spread by midges, and has crossed the Channel from the Continent. Adult animals that contract the virus usually recover, but the young born with birth defects have to be destroyed.

The Animal Health and Veterinary Laboratories Agency (AHVLA) said the infection had now been identified on 74 farms.

Five of the positive cases have been diagnosed in cattle, 69 in sheep, and none to date in other species. So far, none of the affected farms have reported importing animals during 2011 from the affected areas in mainland Europe.

Positive cases have been identified on the Isle of Wight and in Wiltshire, West Berkshire and Gloucestershire. This is in addition to the counties in the east and south of England which have previously had cases identified, namely Norfolk, Suffolk, Essex, Kent, East and West Sussex, Hertfordshire, Surrey, Hampshire and Cornwall.

A spokesman for the Department for Environment, Food and Rural Affairs said: "As everyone connected with the livestock industry has been expecting, the number of cases of Schmallenberg has increased as lambing and calving begin to gather pace.

"Schmallenberg has been identified in the south, south west and east of England, and we suspect livestock got the virus from infected midges blown across the Channel from affected areas in Europe.

"As farmers, vets, and governments continue to gather information about the progress and effects of this disease, it's vital that farmers continue to report any suspicions they have as soon as possible
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"The European Centre for Disease Prevention and Control says it is unlikely Schmallenberg virus would cause disease in humans."