04-12-2008 - Risk of bluetongue spread through animal transit
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Risk of bluetongue spread through animal transit
MORE data are required before a precise estimate can be calculated
for the risk of bluetongue being transmitted by the transit
of animals from or through restricted zones in European member
states, according to the European Food Safety Authority (EFSA
The EFSA's Animal Health and Welfare Panel was asked for an opinion on the matter by the European Commission. It was also asked to study the impact of different control measures in reducing the spread of bluetongue virus (BTV).
In the opinion, which was published on November 18, the panel concluded that BTV could be introduced into a zone that was not under bluetongue restrictions either by infectious Culicoides species midges travelling with animals being transported, or by the transportation of viraemic animals. A lack of data meant it was not possible to assess the risk of introducing BTV into a non-restricted zone by the release of infectious Culicoides travelling with animals. However, the panel suggested that treatment of animals and vehicles with repellents or insecticides before loading might help to reduce the risk of transporting infectious midges, although more research was needed.
With regard to the risk posed by transporting infectious animals, the panel said that currently available data were insufficient to provide a precise estimate of the actual risk posed by moving a single animal. However, it considered several scenarios in which different risk mitigation options were applied.
The risk posed by moving animals during a 'vector-free period' was 'substantially lower' than that of moving them during other periods, the panel said, although it was not possible to assess the effect precisely. Also, vaccination might be more effective than pre-transport testing in reducing the risk of transmission when moving animals.
The panel also concluded that it was difficult to assess the risk of BTV transmission to naive animals moved through restricted zones because of the difficulty of estimating parameters associated with vector biology.