Schmallenberg slide show

School of Veterinary Medicine and Science

Schmallenberg virus in Europe

Tarlinton, R., Daly, J., Dunham, S., Kydd, J.


Schmallenberg why the fuss?

• Discovered in cattle with diarrhoea in Germany and the Netherlands in Autumn 2011

• Genetically very similar to a group of viruses (Akabane virus) known to cause birth defects in calves and lambs in Australia and Japan

• Mostly affect ruminants (sheep, goats and cattle in particular)

• Tests and monitoring therefore developed• Over 6000 farms in Northern Europe reported deformed

lambs or calves in spring/summer 2012 • http://www.youtube.com/watch?

v=jtZ7kDTQWMM&feature=player_embedded#!


How the viruses work• Generally cause mild or no

disease in adult animals (diarrhoea in cattle)

• If a pregnant animal is infected the virus replicates in the nerve cells of the foetus

• This (depending on when the animal is infected) leads to:– abortion– abnormalities of the bones

and joints due to failure of normal muscle development

– neurological deficits due to failure of brain development

Photos courtesy of Amanda Straughton and Jennifer Price


How does Akabane behave in Australia and Japan?

• It is spread by biting midges• In endemic areas most

animals are infected pre-puberty and are immune

• Only sporadic abortions/deformities are seen

• If weather conditions change the range of the vector may extend resulting in large numbers of naive animals being infected

• This leads to large-scale outbreaks of foetal deformities

Photo: culicoides.net


What we know now• The virus has been found in

Culicoides sp midges and this is probably how it is spreading in Europe

• Unfortunately these midges are found all over Europe

• Most cattle and sheep in the area where the virus was first identified have had it. It is assumed that they are immune and won’t have another affected calf or lamb

• It is spreading throughout the UK and other parts of northern Europe that didn’t have it last year at the moment Map courtesy of Flu

trackers.com October 2012


The UK as of Jan 2013• The virus definitely circulated in the UK in summer/autumn

2012• 976 holdings across most of England and Wales have been

exposed to the virus (AHVLA Dec 2012).• Also first cases in Northern Island • Vets who have been sending bulk milk samples from diary

herds to BioBest laboratories to test for antibodies are reporting that almost all herds have been exposed

• Anecdotal reports of large numbers of ewes scanning empty

• Data from our own indoor herd would indicate that we have a lower percentage of animals exposed (25%) compared with the 70-100% reported in Belgium and the Netherlands


The likely impact• There are likely to be deformed lambs and calves

born in spring/summer 2013• Numbers will vary from farm to farm as the

deformities will depend on what stage of pregnancy the animals were at when infected.

• Data our students collected last year demonstrate that losses may be as high as 30% on some severely affected holdings

• The virus will most likely circulate in further years (we have the midges)

• Merial have announced vaccine trials but it’s not likely to be available till next year at the earliest

Schmallenberg slide show

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