1. Schmallenberg virus in
Europe
Tarlinton, R., Daly, J., Dunham, S., Kydd, J.
School of Veterinary Medicine and Science
2. 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 affects ruminants (sheep, goats and cattle in
particular)
• Tests and monitoring therefore developed
• More than 6,000 farms in Northern Europe reported
deformed lambs or calves in spring/summer 2012
• http://www.youtube.com/watch?
v=jtZ7kDTQWMM&feature=player_embedded#!
School of Veterinary Medicine and Science
3. How the virus works
• Generally causes 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
School of Veterinary Medicine and Science
4. 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
Photo: culicoides.net
• This leads to large-scale
outbreaks of foetal
deformities
School of Veterinary Medicine and Science
5. What we know now
• The virus has been found in
Culicoides 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 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
School of Veterinary Medicine and Science
6. 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 Ireland
• Vets who have been sending bulk milk samples from dairy
herds to BioBest laboratories to test for antibodies are
reporting almost all herds have been exposed
• Anecdotal reports of large numbers of ewes scanning
empty
• Data from our own indoor herd would indicate we have a
lower percentage of animals exposed (25%) compared with
the 70-100% reported in Belgium and the Netherlands
School of Veterinary Medicine and Science
7. 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
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)
School of Veterinary Medicine and Science
