Scientific Opinion on African swine fever

The risk for endemicity of ASF in the eastern neighbouring countries of the EU and spread of ASFV to unaffected areas was updated until 31/01/2014. The assessment was based on a literature review and expert knowledge elicitation. The risk that ASF is endemic in Georgia, Armenia and the Russian Federation has increased from moderate to high, particularly due to challenges in outbreak control in the backyard production sector. The risk that ASFV will spread further into unaffected areas from these countries, mainly through movement of contaminated pork, infected pigs or contaminated vehicles, has remained high. In Ukraine and Belarus, the risk for ASF endemicity was considered moderate. Although only few outbreaks have been reported, which have been stamped out, only limited activities are ongoing to facilitate early detection of secondary spread. Further, there is a continuous risk of ASFV re-introduction from the Russian Federation, due to transboundary movements of people, pork or infected wild boar. The number of backyard farms is greatest in the west of Ukraine and westwards spread of ASFV could result in an infected area near the EU border, difficult to control. In Georgia, Armenia and the Russian Federation, the risk for endemicity of ASF in the wild boar population is considered moderate, mainly due to spill-over from the domestic pig population, whereas in Ukraine and Belarus this was considered to be low. In those areas in the Russian Federation where wild boar density is high, this risk may be higher. Intensive hunting pressure in affected wild boar populations may increase the risk for spread, possibly with severe implications across international borders. The risk for different matrices to be infected/contaminated and maintain infectious ASFV at the moment of transportation into the EU was assessed and ranged from very high for frozen meat, to very low for crops

Protection of European domestic pigs from virulent African isolates of African swine fever virus by experimental immunisation

African swine fever (ASF) is an acute haemorrhagic disease of domestic pigs for which there is currently no vaccine. We showed that experimental immunisation of pigs with the non-virulent OURT88/3 genotype I isolate from Portugal followed by the closely related virulent OURT88/1 genotype I isolate could confer protection against challenge with virulent isolates from Africa including the genotype I Benin 97/1 isolate and genotype X Uganda 1965 isolate. This immunisation strategy protected most pigs challenged with either Benin or Uganda from both disease and viraemia. Cross-protection was correlated with the ability of different ASFV isolates to stimulate immune lymphocytes from the OURT88/3 and OURT88/1 immunised pigs