Scientists are calling for more research into the effects on wildlife of a livestock virus which has spread throughout much of Western and Northern Europe.

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Schmallenberg virus, which was first discovered in autumn 2011, expanded its spread over summer 2012 when midges which transmit the disease became most active; the Virus now covers an area of Europe stretching from Spain and Italy in the South to Norway and Finland in the North.  As Schmallenberg is not a notifiable disease and has been detected in most regions of the worst hit countries, many veterinary agencies have ceased reporting and advanced surveillance activities.

However, systematic serological testing has revealed that the majority of adult cattle, sheep and goats in affected regions have been exposed to SBV. In addition to this, populations of wild animals including deer are known to have been exposed, if not affected. Although its rapid spread is cause for concern, animals exposed to the disease are thought to develop resistance.

Even so, livestock groups across Europe have expressed eagerness for a vaccine. Industry leaders gathered at the Welsh National Sheep Association's annual meeting this week called on government and research institutes to expedite the licensing of an SBV vaccine, which could be available later this year. SBV was detected in Wales for the first time in 2012.

Meanwhile, researchers in Belgium have called on European institutions to increase the study of the virus' effects on wildlife. Veterinarians from the Université de Liège told the BBC on Wednesday that surveillance should be expanded to include wild animals.

In 2012, Belgian veterinary scientists led by Dr Annick Linden examined blood samples taken from 524 red deer and roe deer shot in the 2010 and 2011 hunting seasons. The team discovered evidence of exposure to Schmallenberg in 43 percent of deer from 2011, but 0 percent of animals from 2010, illustrating in Linden's words, "that SBV had quickly spread since its emergence [around] 250 km northeast during late summer 2011."

The researchers found no evidence of aborted or deformed foetuses associated with Schmallenberg infection in cattle and sheep, they said that "newborn fawns are almost impossible to collect in the wild [as they are] quickly eaten by scavengers, and the absence of SBV-specific genetic material or morphologic alterations… are not evidence of noninfection," meaning the virus' effects on deer remains unclear.  

While roe deers' gestation period and breeding habits may protect foetuses from the effects of Schmallenberg, which can cause foetal abnormalities or stillbirth if contracted during early pregnancy, Linden and her team suggested red deer may be more at risk.

In addition to its effects on foetuses, SBV can cause sickness and milk drop in cows, though the effects on sheep at the time of infection appear to be minimal. Although Defra has requested all farmers observing abnormalities inform their vet, the department also advised in late 2012 that farmers "discuss with their vets… the cost benefit of vaccinating against a disease which spreads so rapidly among a naive population and causes only a low impact."

Although Defra is treating the disease as 'low impact,' its effects may have been felt most severely by farms with early lambing flocks, which reported higher than anticipated losses in December and January.

Similar effects were seen last year, although AHVLA Told Farming Online in January there are currently "no definitive figures" to support the observed pattern, with investigation made especially problematic by the fact SBV remains a novel and non-notifiable disease. An AHVLA spokesperson said this is "something we are looking into."

The latest AHVLA testing results, released in January showed a marked rise in the number of cases from December, as lambing progressed in the UK. SBV cases in England and Wales rose by 24 percent over the period, though by mid-month there had been no cases reported in Scottish animals.

Also in January, NFU said that the cost for individual businesses of SBV infection can run into thousands of pounds, and, calling for the rapid development and deployment of a vaccine, that the issue is especially serious as the outbreak has coincided with a three year low for lamb prices and rising input costs.