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The first case ever of Bluetongue in the UK
James Irvine
Teviot Scientific, Cultybraggan Farm, Comrie,
Perthshire
Filed 23 Sep 07
©www.land-care.org.uk
It was virtually inevitable that Bluetongue virus
would find its way from Northern Europe, where it is currently rampant,
to reach the UK. After all, there is plenty of traffic going to
and fro between the two areas. Even a suitable wind might be enough
to transport the midges, that are the carriers of the virus, across
the English Channel or even the more southerly parts of the North
Sea. All the midges need in order to be active is a temperature
above 15 deg C and some cattle, sheep, goats or deer (as well as
people, of course) to feed on.
It is therefore surprising that Bluetongue has
not reached at least the south of England before now. Its presence
in a Highland cow at Baylham House Rare Breeds Farm, near Ipswich,
Suffolk was established yesterday, 22nd September 2007.
Culicoides impunctatus
An electron micrograph of
the prominent biting midge of Scotland
Photograph kindly provided by
Dr Alison Blackwell, Advanced Pest Solutions Ltd,
University of Edinburgh.
Baylham House Farm is a small rare breeds farm
on the River Gipping with sheep, cattle, poultry, pigs and goats.
It is near Ipswich and close to England's south east coast. It runs
a holiday enterprise in a self-contained unit in an old listed farmhouse,
Baylham House Farm Annexe. Among the facilities listed, is a working
farm. The facility, also listed, that French is spoken may be relevant
in so far that tourist from Northern Europe, including France, may
be attracted to the Farm and its diversification into tourism.
The location close to the sea, with sea ports
nearby, is likely to be highly relevant. Midges carrying BT may
have been brought into the area on visitors clothes, vehicles or
miscellaneous goods. Also advertised in the Farm's tourist promotion
are walks in the country, presumably including walks on the working
farm. This would make it all the easier for Bluetongue virus carrier
midges to make the short step from the garments of a tourist to
a cow, sheep or goat , where it can get its meal.
Or it could have been blown across the North Sea.
Or it could have come across from Northern Europe aboard a boat
that moored in a local harbour.
The strain of Bluetongue virus detected at Baylham
Rare Breeds Farm in Suffolk is, not surprisingly, the same (BT8)
as that causing so much trouble in Northern Europe since August
2006.
Presumably the infected cow was spotted because
it was showing clinical signs. That would mean that the unfortunate
beast could have infected hosts of other midges in the viraemic
preclinical stage of the disease. It would be remarkable if the
single cow so far identified to have Bluetongue will turn out to
be a one-off case.
Midges are only active at temperatures of 15 degC
or above. The forecast is for the temperature to fall, but not until
Tuesday. And it may not fall far enough. A lot of damage in terms
of spread of disease could happen before then.
The statements from Defra keep talking about
"tests being done to confirm ..".
What we are not told is whether or not Defra,
through its Animal Health Division, is using on-site real-time RT-PCR
machines, and whether these machines are being used to detect viraemia
in the preclinical stage of the disease that is likely to be affecting
the other cattle, sheep and goats on the index farm and on neighbouring
farms. These results are capable of being available in a mater of
an hour or so. The suspicion is that Defra has not invested in the
purchase of such equipment, and that all sample are required to
go to Pirbright in Surrey.
The pronouncement by Deputy Chief Veterinary Officer
Fred Lan berg, that
"it was possible that some infected midges
had been blown over from mainland Europe and the disease could
be localised to the area"
seems overlay optimistic.
He went on to say that
"The case was not being treated as an outbreak,
although if further cases emerge, contingency plans to prevent
its spread such as animal movement restrictions would be put in
place."
So the index beast was slaughtered and animal
movements in the area are allowed to continue. although beasts in
the preclinical phase may be viraemic. Somehow this does not make
sense.
But there is very little that can be done about
midges spreading the disease among themselves and then on to other
livestock, according to how the wind blows, what tourists can carry
on their clothes and, of course, whether the temperature remains
above 15 dg C for the midges to be active. The only chance is that
the type of midges that got on to the farm from the continent cannot
spread it to the type of midges that are local. Allegedly, not all
types of midge are capable of carrying the virus. Those of us in
Scotland would, for example, dearly like to know whether the common
biting midge that plauques our land is suceptible or not. It would
be an extraordinary piece of luck if the local midges in Suffolk
were of a type that did not pick up the BT8 virus, and if it turns
out that the Northern European midges cannot survive in Southern
England.
Seemingly, the amount of research that has been
funded in this area has been small, so we are unlikely to have the
answer in as much detail as we would like.
According to Defra
"There are no bluetongue vaccines suitable
against the outbreak of bluetongue in northern Europe".
Is that because they do not exist, or because
they are not licence? Could it be that not having a licence might
reflect the Government's anti-vaccination policy? Or id the government
never order VT vaccine that matched the type of BT that has been
infecting Northern Europe for over a year, and many part of the
globe long before that. Or is it because what vaccines are available
are directed toward different strains of BT virus? For some reason,
it always seems so difficult to find out exactly what the facts
are.
The problem highlights the unsatisfactory situation
in terms of vaccine production throughout the world. The appears
to be a serious lack of integration between commercial vaccine manufacturers
and the numerous governments that they have to deal with. There
are obvious funding issues. Production schedules, which are likely
to be on a massive scale, may get disrupted by a rapidly changing
disease situation.
BT8 has been a major problem in Northern Europe
since August 2006 and elsewhere in the world for much longer than
that. A number of European Member States are now crying out for
vaccination against BT8. The European Commission makes noises about
the problem, but somehow the whole business of creating a EU policy
on the matter and EU funding takes far too long. Meantime EU trade
rules, as with other disease outbreaks, stymie trade, in the absence
of the prompt application of accurate, rapid on site tests for viraemia
and antibody production distinguishing between those arising from
infection from those arising through vaccination - should we ever
get round to it)
The upshot is that while the risk of BT8 reaching
the UK has been high for the past year, when the virus does arrive
we are told that there is no appropriate vaccine available.
And so we are told that no suitable vaccines
are available to try and nip this first outbreak in the UK of bluetongue
(in this case, BT8) in the bud. WE are just told to be "vigilant".
Movement restriction remains the only weapon.
Sadly, on this basis Bluetongue in UK livestock
and wildlife will be set to become endemic. Trying to eradicate
it with vaccination would then be a much more difficult task.
©www.land-care.org.uk
References
1. Irvine, James (2007). The Bluetongue
virus threat to UK livestock this summer
See ANIMAL HEALTH - General Homepage, filed 12 Apr 07,
www.land-care.org.uk Click
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