Note on Bluetongue

In the last 15 years the EU has experienced the appearance of vector-borne viruses never seen before in any MS. Events such as the recently introduced exotic serotype 8 of Bluetongue virus and the outbreaks in wild birds in Austria and Switzerland of the Flavivirus named Usutu virus (and other vector-borne diseases such as West Nile Fever in other EU countries) are indicators of possible emerging threats in the EU for which the harmful impact on animal health or public health may be difficult to assess. These introductions can represent complex challenges for risk managers at both the level of MS and the EU, who have to determine the extent of the problem and implement control measures to contain the spread. In addition, they have to manage many areas of uncertainty, such as, when the introduction occurred, how it occurred and how often and whether these vector-borne diseases will become endemic in the EU.

The route through which such vector-borne diseases have been introduced into EU is often not clear, and a multi-disciplinary approach is required to be able to identify the source, ranging from tracing of animal/product movements to more sophisticated knowledge of virus and vector biology.
Knowledge of vector biology and ecology is fundamental to the understanding of how these diseases behave and may become established in the EU. In this context, coordinated trans-border efforts are required not only when attempting to control the disease, but also in sharing the new knowledge that could become available about these exotic vector-borne viruses.

Moreover, scientific expertise and further studies are needed to understand whether the spread and possible persistence of these diseases are the results of environmental changes or a viral evolution which facilitated the role of other vectors.

These types of events have to be carefully monitored and analysed (perhaps including vector monitoring) to provide reassurance that the current surveillance systems will allow their detection at the earliest stage and provide the risk managers with sufficiently detailed data.

Bluetongue is a disease transmitted by flying vectors, consequently it is a trans-boundary disease. The epidemiological situation in one member state may therefore affect its neighbours and focussing purely on national control efforts tends not to be sufficient. Instead, an integrated and comprehensive approach is required including analysis of the distribution and competence of potential Culicoides vectors in the EU regions and around the EU. Data collection and analysis would benefit from increased networking among Member States and countries surrounding the EU. In particular, the implementation of international surveillance networks permits a continuous risk assessment of the Bluetongue situation with particular reference to the epidemiological and ecological aspects related to the presence and abundance of competent vectors.

In the present situation with ruminants being infected with Bluetongue virus of serotype 8, the following is necessary in order to be able to carry out meaningful risk analyses:

• To harmonize collection of epidemiological data.
• To harmonize the sampling procedures (blood for antibodies and PCR testing).
• To share these information as quickly as possible.
• To monitor and study the spatial and temporal pattern of potential and known vector occurrence
• To investigate the origin of the introduction of bluetongue serotype 8 to the EU which could be related to various factors such as, importation of infected live ruminants, introduction of infected vectors with non-susceptible live animals or insect introduction through plants

AHAW Scientific Panel Members
The Scientific AHAW Panel adopted the current Note on Blue tongue by written procedure on the 19th of September 2006.

Members of the AHAW Panel are :
Bo Algers, Harry Blokhuis, Donald Broom, Patrizia Costa, Mariano Domingo, Matthias Greiner, Daniel Guemene, Joerg Hartung, Trevor Hastings, Per Have, Frank Koenen, David Morton,, Christine Müller-Graf, Dirk Pfeiffer, Mo Salman, Moez Sanaa, Michael Sharp, Philippe Vannier, Martin Wierup and Marion Wooldridge.