The Use of Risk Assessment to Decide the Control Strategy for Bluetongue in Italian Ruminant Populations

Abstract

The affiliation, assessment and management of risks is a traditional part of veterinary medicine. In the past, veterinary services involved in this type of activity usually assessed risks qualitatively. However, since the 1990s, quantitative methods have become increasingly important. The establishment of the World Trade Organization in 1994, and the promulgation of its Agreement on the Application of Sanitary and Phytosanitary Measures (the "SPS Agreement") led to an increased application of import risk analysis and to significant improvements in the methodology of risk analysis as applied to international trade policy for animals and animal products. However, there was very little development of risk analysis in veterinary fields other than international trade and management of health risks to consumers of animal products and little has been published on its use in the choice and definition of control or prophylaxis strategies for animal diseases. This article describes a quantitative risk assessment, which was undertaken in Italy to help choose an appropriate national response strategy following an incursion of bluetongue, an infectious disease of sheep and goats. The results obtained in this study support the use of risk analysis as a tool to assist in choosing an appropriate animal disease management strategy. The use of risk analysis in the evaluation of disease management strategies also offers advantages in international trade. It makes easier the comparison of different strategies applied in the various countries, and thus facilitates the assessment of equivalence of the guarantees provided by different strategies.

Bluetongue control strategy, including recourse to vaccine: a critical review

“…As an example, the spread of BTV-4 in an unvaccinated ruminant population in 2003 in Sardinia closely resembled the pattern and rapidity of spread of BTV-2 in the same population in 2000 [32]. The sole exception was BTV-16 the spread of which modified after entering Italy after the use of a modified live virus (MLV) vaccine that was eventually demonstrated to be inadequately attenuated.…”

“…Europe was not fully prepared to face a vector-borne epidemic of the magnitude of the bluetongue epidemic that started in 2000 in the Balkans and in central and western Mediterranean [32].…”

“…An intensive surveillance and research effort had been launched since 2000 in the individual affected EU member states to identify vector presence, abundance and dynamics as well as establish BTV epidemiology in the European context [4,30,32,38,56,63]. While these studies were able to describe the epidemiological evolution of bluetongue in Europe, they also demonstrated the existence of other competent Culicoides spp.…”

“…The 20 km, protection and surveillance zones were merged and standstill measures limited in southern Europe only after the implementation of surveillance systems and the mass vaccination of susceptible species. Changes to the restrictive levels between territories in southern Europe were based on a risk analysis that evaluated the effects of vaccination [36], sensitivity of sentinel systems [9] and probability of BTV spread by animal movements [33].…”

“…The intra-European transboundary spread of bluetongue, until 2006, has only been documented from Sardinia to Corsica [59] and suspected from Greece to Italy [32,33], probably because the effort made by affected individual countries had limited the spread of infection within each country. The need to harmonise national information systems and the implementation of an integrated bluetongue information system was not considered necessary to be compulsory by neither the EU or by the member states until BTV-8 spread to northern Europe.…”