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Project Background
Despite intensive efforts, it has been proved that it was not possible
to eradicate CSF from Europe. The disease is still a major cause of
economic loss to member states of the EU. In 1993 and 1994, 10.7 and
21.4 million Euros respectively were spent on outbreaks in Belgium
and Germany, with a further 130 million Euros of market support in
1994. In 1997, an epizootic centered on The Netherlands resulted in
the compulsory slaughter and disposal of 10 million pigs, with costs
estimated at over one billion Euros. An estimation of the overall economic
loss results in several times these amounts. Currently a non-vaccination
policy is implemented in the EU, but due to the problems in wild boar
some field trials are ongoing using the live C-strain vaccine since
a live vaccine is necessary for oral vaccination. The disadvantage
of this vaccine is that no differentiation between vaccinated and infected
animals can be made. Therefore there is a need for a live maker vaccine.
The recurrence of CSF in domestic pigs in Europe is facilitated by a
wild boar reservoir of the disease, and by sporadic reintroduction to
domestic pigs through contacts with infected wild boar and also by illegal
swill feeding practices. The clinical picture has also changed in recent
decades, shifting to a more sub acute or even sub clinical disease appearance,
which is even more pronounced in wild boar. This makes early recognition
of new outbreaks more difficult. At the same time, changes in farm production
resulting in greater geographical concentration of pig numbers and increased
movements of pigs and potentially contaminated pig products have exacerbated
the consequences for reintroduction of the disease within the domestic
pig population. Taking into consideration that about 80% of the first
outbreaks of CSF in domestic pigs occurred in regions where CSF is endemic
in wild boar, controlling CSF in wild boar is an indispensable prerequisite
for keeping domestic pigs free of CSF.
Wild boars are an indigenous species in Europe and they should be managed
as a part of our natural environment.
A better understanding of the transmission of CSF in wildlife and from wild
life to farmed animals will be possible due to the epidemiological analyses
and the application of the model outputs. Models will also support new strategies
to avoid CSF transmission. Since the development of a new vaccine takes several
years before it is registered we will start to modify the baits with a C-strain
in order to increase their intake rate by piglets; current vaccination program
fail in reaching young wild boars and thus leaving them susceptible. If young
animals are not well vaccinated, CSFV can be maintained in the population.
In parallel a marker vaccine will be developed. This new live attenuated marker
vaccine for oral administration in wild boar, based on an already available
infectious clone of an a virulent CSFV-strain (P3 and P6), in combination with
an epidemiological and economic model, will improve strategies to prevent introduction
and spread of exotic agents and its transmission between species. It will also
reduce interventions such as whole scale slaughter of affected populations.
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The problem affects different countries within Europe, and decisions
on CSF control policy are taken at a community rather than at national
level. Before decisions are taken it is important to have scientific
tools available to estimate the risks, the benefits and the costs of
a possible intervention.
Socially, large-scale outbreaks of CSF have a disastrous economic effect
on local farming communities, and public opinion perceives mass killings
of animals as unethical. Animal welfare implications of CSF outbreaks
are also serious. Research into ways of preventing such outbreaks will
mitigate such disruptions.
Therefore a multinational and multidisciplinary research effort is appropriate
and will contribute to realise the objectives of the priority thematic
area.
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