Semi-quantitative risk assessment by expert elicitation of potential introduction routes of African swine fever from wild reservoir to domestic pig industry and subsequent spread during the Belgian outbreak (2018-2019).

Since the introduction in Georgia in 2007 of an African swine fever (ASF) genotype 2 virus strain, the virus has rapidly spread to both Western European and Asian countries. It now constitutes a major threat for the global swine industry. The ongoing European transmission cycle has been related to the 'wild boar habitat' with closed transmission events between wild boar populations and incidental spillovers to commercial and non-commercial (backyard) pig holdings. During the epidemic in Belgium, only wild boar were infected and although the introduction route has not yet been elucidated, the 'human factor' is highly suspected. While ASF was successfully contained in a small region in the Southern part of Belgium without affecting domestic pigs, the risk of spillover at the wild/domestic interface remains poorly assessed. In this study, we used a semi-quantitative method, involving national and international experts, to assess the risk associated with different transmission routes for ASF introduction from wild boar to domestic pig holdings and subsequent dissemination between holdings in the Belgian epidemiological context. Qualitative responses obtained by our questionnaire were numerically transformed and statistically processed to provide a semi-quantitative assessment of the occurrence of the hazard and a ranking of all transmission routes. 'Farmer', 'bedding material', 'veterinarian' and 'professionals from the pig sector' were considered as the most important transmission routes for ASF introduction from the wild reservoir to pig holdings. 'Animal movements', 'farmer', 'veterinarian', 'iatrogenic', 'animal transport truck' and 'animal care equipment' were considered as the most important transmission routes posing a risk of ASF spread between pig holdings. Combined with specific biosecurity checks in the holdings, this assessment helps in prioritizing risk mitigation measures against ASF introduction and further spread in the domestic pig industry, particularly while the ASF situation in Western Europe is worsening.

Measuring general animal health status: Development of an animal health barometer.

The development of an animal health barometer, an instrument to measure the general health of the Belgian livestock population on a yearly basis and to monitor its evolution over time, is described. The elaboration of a set of 13 animal health indicators (AHIs) as the basis for the animal health barometer is discussed. These indicators were weighted by experts - including scientists, policy makers and agro-industrial representatives - to determine their relative weight in the barometer. The result of the barometer is expressed as a comparison with a previous year. Based on the results of the 13 AHIs, it is concluded that general animal health in Belgium shows a positive evolution since 2008. The animal health barometer provides a composite view of the status of livestock health in Belgium and is a tool to communicate in an intelligible, comprehensible manner on aspects of animal health to consumers and professional stakeholders in the animal production and food chain. Together with the food safety barometer (Baert et al., 2011. Food Res. Int. 44, 940) and the plant health barometer (Wilmart et al., 2014. Eur. J. Plant Pathol. doi: 10.1007/s10658-014-0547-x), the animal health barometer is one of the three instruments to provide a holistic view on the overall status of the safety of the food chain in Belgium.