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Bluetongue serotype 8 vaccination policy
for England and Wales.
Dr Ruth Watkins
Sheep Hill Farmer, Wales
Formerly, Consultant Clinical Virologist, St Mary's Hospital, London
Filed 03 Nov 07
©Ruth Watkins
This article
should be read in conjunction with
the author's article on vaccination policy (1).
.
The goals are:
1. Damp down and confine the re-emergence of BTV
disease in 2008.
2. Protect our East and South coasts from new
plumes of infected midges.
3. Allow trading to proceed during 2008, as near
normal as possible, bearing in mind new infections of bovines will
be infrequent before June 2008, after the first season of infection
ends in January 2008.
4. The main sheep trade is from September when
sheep from the East go to grazing in the West and rams are traded.
5. To prevent any circulation of the virus in
2009.
Scotland is further from the restriction zone
and will produce a separate policy
Actions to be taken
Order BTV-8 vaccine sufficient million doses as
set out below NOW.
Relicense Merial at Pirbright to manufacture
BTV-8 vaccine only (this is no longer a containment level 3 veterinary
virus in the British Isles)
Do not wait to see which way different countries
in Europe will jump- they will be vaccinating and our nearest neighbours
have a hyperendemic BTV-8 infection this summer and should follow
a plan close to that set out in my vaccination policy for zone A.
Prepare our own policy for BTV-8 vaccination
with veterinary surgeons - private or SVS, supervising farmers doing
the vaccinating, so government vaccine is properly given. (farmers
can form bands and so help each other in the parish)
Expect first millions of vaccine doses (at least
20 million) to be delivered in June 2008.
Vaccinate all cattle (domestic bovines) throughout
England and Wales. This is set out in my policy and every single
one should receive the doses (2) of the vaccine to produce primary
immunity. (If any cattle have a prior positive test demonstrating
infection with BTV-8 then they would be the only exceptions as nothing
is to be gained vaccinating them, the vaccine is wasted, and they
will never need vaccination). Free trading in England and Wales
60 days after vaccination completed (or before the beginning of
June 2008 regardless of vaccination).
Vaccinate all the other domestic ruminants in
the control zone as it has been applied in January 2008 when all
new cases can be expected to cease for at least 4 months. This means
vaccinating all sheep, goats, camelids and domestic deer. This is
because it is here the virus will re-emerge next spring in earnest
and the disease will become hyperendemic without vaccination, as
has happened in Europe during the summer of 2007. If this vaccination
is completed (adults as well as young) by the end of July they can
be moved 60 days later to the West if required for grazing etc,
thus freely traded to unvaccinated as yet areas of England and Wales
after the end of September.
Vaccinate all designated
breeding rams, camelids and domestic stags intended for breeding
stock- 2009 in the case of sheep - the 2008 rut for deer and - ?year
for camelids before July if possible. There appear to be problems
with long term fertility even in the case of unapparent infection
in males, quite apart from infectivity of semen.
Expect further delivery of vaccine by the end
of July 2008, the next millions (10 million at least).
Vaccinate in August all the other domestic ruminants
within 50 miles of the East coast and South coast where midge plumes
may land in 2008. (Unfortunately unless our neighbours vaccinate
all their young non-immune ruminants there will be considerable
infection again in NW Europe)
Vaccinate in August all the other domestic ruminants
in the restriction zone as drawn up in January 2008, see above.
Surveillance by bloods for virus RNA by RT-PCR
should be done on the flocks as vaccination is proceeding to see
if there is infection other than that investigated because of illness.
If no infection is unearthed in these areas then
the sheep can be traded. If an area has an infection the control
zone should perhaps wait 60 days before trading can begin. Or this
could be reduced to 21 days (the usual length of time that infectiousness
can be documented experimentally by midge or blood inoculation transmission
in sheep) because further vaccine is coming on line to vaccinate
the remaining other ruminant flocks of sheep, herds of goats, and
camelids that autumn and winter throughout the rest of England and
Wales. The trading can begin by the end of September from the new
control zones. There is no panic if infection and disease is diagnosed
because vaccine can be applied in the flock and the neighbouring
flocks.
Winter 2008 / 2009 vaccinate all the other ruminants
as above in England (the North-West and South-West) and Wales.
The summer of 2009 all young ruminants
will have to be vaccinated, see my policy about keeping up with
the young-stock. A year after initial vaccination a booster will
be due. Susceptible ruminants will be at risk of infection, so the
need is to keep these as low in number as possible (see my policy
for the reasons).
The purpose of the policy
The whole point of the policy is to allow
trade to resume to near normality in a controlled way without introducing
the BTV-8 virus chaotically to areas of the SW and NW of England
and Wales where it is unlikely to be established during 2007. Otherwise
the whole livestock business and all the other subsidiary businesses
will grind to a halt.
The vaccine order should be something like:
40 million doses (20 million courses) by June
2008
20 million doses (10 million courses) by the end
of July 2008
sufficient to vaccinate the rest of the national
flock autumn winter of 2008 / 2009
sufficient to vaccinate all young-stock by summer
2009
sufficient to re-vaccinate
all adult stock (one dose per ruminant) in 2009.
Who pays?
The vaccines will be funded by the EU as this
is a policy to control BTV-8 in England and Wales, and should eradication
be possible this will be achieved as well in 2009. The EU will also
fund half the cost of vaccination.
(Bankrupt DEFRA is saved and so are the livestock
farmers of England and Wales)
©Ruth Watkins
References
1. Watkins, Ruth (2007).
Vaccination against Bluetongue serotype 8: a proposal for discussion.
See ANIMAL HEALTH - GENERAL Homepage, filed 01 Nov 07,
www.land-care.org.uk Click
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