Vaccine should first be made available to livestock on the borders
of infected zones; this is the advice of Belgium, Suffolk sheep
breeder Jan Van Grinderachter, whose own sheep contracted the virus
in August 2007.
Jim Fleming, retiring chairman (left) and Van Grinderachter guest speaker at the annual meeting.
He warned that in Belgium they suffered just 60 cases in 2006
which escalated to 2,500 infected farms in 2007. It is likely he
claims that the same pattern will wreak havoc in the UK’s
livestock industry if the vaccine is not used quickly and wisely.
Speaking to some 80 members of he Suffolk Sheep Society at the
annual meeting in Derbyshire, last week (28.2.08) he described
the devastating affects the disease has had on Belgium livestock
Jan explained: “Bluetongue is a virus disease, but it needs
hosts and vectors – transmitters, the midge is the transmitter.
We have a lot to learn, but we can tell you there are 24 types
of bluetongue serotypes, we and the East of the UK have BTV8, which
has never been seen before in Europe, not even in North Africa.”
Bluetongue, which was previously recognised as a sub tropical virus,
did hit Cyprus in 1943 and then Portugal and Spain in 1956, where
they suffered 200,000 losses, before the virus disappeared three
“We believe the most likely route for the midge into Europe
this time was in flowers and fresh produce to air and sea ports,
and once here 2006 was exceptionally warm. The midge itself, culicoides,
is not new to Europe, but the fact that they carry the virus is.
“They are most active one hour before sunrise and one hour
before sunset – and on a dull day they could well be active
throughout. It is only the females that bite with activity influenced
by temperature – the optimum is 20 – 35 degrees centigrade.”
Jan said in Belgium monitor midge traps have demonstrated that
the midge does operate in sheds and not just outside. Once infected
by the saliva of the female midge it enters the body of the host
and replicates in the blood stream; it depends on whether they
make antibodies quickly as to whether they survive.
He said warning signs are not always obvious: “Some animals
you see and think will die, but they survive others look ok and
two days later they are dead. Symptoms include excessive saliva – forming
a white beard, blood in the mucus in the nose, inflammation of
the mouth, oedema – a lot of white eye visible, lameness
and stiffness, depression and doziness. Loss of appetite, reproductive
disorders and secondary infections are also symptomatic.”
The Belgium, who lost five of his own flock of some 60 ewes, says
regular inspection of stock – at least twice a day is imperative.
However treatment should not be started until symptoms are seen,
because fever is needed to start the immune system. New needles
for each case are imperative.
While a small number of whole flocks have been wiped out, many
have encountered massive problems with fertility; for Jan’s
own flock this means 25 of 48 ewes are not in lamb. In dairy cows
it has cost an average of £160 per cow on affected units.
He urged farmers to not get stock too fat and ensure they receive
adequate vitamins and minerals to keep the immune system strong: “If
they have a reserve of vitamin E and selenium it helps.”
To minimise risk of infection, housing before sunrise and sunset
does help, however Jan is sceptical that chemical sprays had been
little use, the use of garlic and citronella were not proven either.
He warned: “In 2006, the vector free season in Belgium did
not start until December 16, 2006, and it ended on March 30, 2007.
The first choice of the midge is cattle and certainly some breeds
of sheep are more susceptible than others, Texel being one breed
at greater risk.
“For this summer what UK farmers need is an inactive vaccine,
Europe has banned live vaccine. Furthermore the inactive vaccine
can be used at any stage.” However he warned that it will
only last six months, therefore it will be required every year.
Although once subjected to the disease animals build their own
immunity. “If a different serotype of Bluetongue were to
appear a different vaccine would be required,” he added.
For more information and a diary of Jan’s first hand experiences
in August 2007, visit www.suffolksheep.org
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Bluetongue Vaccine Needed to Extinguish Disease