Tense farmers are preparing for the worst this lambing season after what appears to be an outbreak of the deadly Schmallenberg virus.

Schmallenberg is carried in midges and causes deformities and death in lambs if the ewe is infected during pregnancy.

A common deformity is the conjoining of limbs.

Cases of Schmallenberg have been confirmed at 74 farms across the UK, as well as many more across northern Europe, France, Germany and the Netherlands.

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A mother sheep sniffs her Schmallenberg virus-infected offspring (Kreisverwaltung)

As well as sheep, the virus can infect other livestock such as cattle and goats, and can cause fever and diarrhoea.

The first victims were discovered at the end of January on farms in Norfolk, Suffolk, Kent, and East Sussex.

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A dead lamb's contorted shape reveals the horrific nature of the Schmallenberg virus (Diatribes of a Veterinarian)

No cases of Schmallenberg have transferred to humans, though the European Centre for Disease Prevention and Control said the risk of human infection could not be excluded.

"The apparent increase in geographical area in the UK from which cases are being detected is still within our expectations based on the risk zones," said an assessment by the Department for the Environment and Rural Affairs (Defra).

"We continue to urge farmers to report to their vets about signs of congenital deformities in newborn animals."

"The new cases are in areas with greater livestock densities, so we may expect more cases to be reported in time."