Bluetongue in Northern Europe: an OIE Reference Laboratory makes a breakthrough in identifying the vector causing the disease
The OIE Reference Laboratory in Teramo , Italy established that an insect native to Northern Europe acted as the vector responsible for the recent bluetongue outbreaks in Northern Europe . The vector, a biting midge of the culicoides species was identified as Culicoides dewulfi while previously it was thought the biting midge responsible for the current spread of the disease might be Culicoides imicola which is commonly found in Africa .
“It is a new epidemiological event because previously all bluetongue outbreaks in Southern Europe were linked to the African vector. This suggests the disease could now become endemic in all the region with the risk of more cases occurring in spring and summer when the vector activity becomes very high”, Dr Bernard Vallat, Director General of the World Organisation for Animal Health said during a meeting of an OIE expert group on the disease.
Following outbreaks occurring for the first time in Belgium, The Netherlands and France the OIE called for best world veterinary experts on bluetongue to advise the OIE Specialist Commissions and Member Countries on reviewing and advising on the implementation of science based standards and guidelines for the containment and control of the disease as well as continuation of safe trade in live animals. Gathered at the OIE headquarters in Paris on Friday October 20 th 2006 , the scientists included Dr Rudi Meisswinkel responsible for the finding that a European vector was incriminated for the first time in the spread of bluetongue in the region.
They further established that due to the adaptability of this specific biting midge to European weather circumstances, the virus now has the potential to expand geographically within Europe , which could require from countries to reassess their control and surveillance measures for the disease.
Although the OIE has been reviewing and updating the existing international standards for the control of bluetongue before the crisis, the immediate need is to apply the exisiting OIE standards to contain the disease while ensuring the continuation of safe trade. Surveillance activities for the disease must be intensified even in those areas not previously been regarded threatened by the disease. Vaccination programs recommended by the OIE that would not inhibit trade in live animals between countries must be implemented.
Commenting on the experts’ recommendations, Dr Vallat also urged vaccine manufacturers to proceed in the development of inactivated and other more technology advanced vaccines that would have the potential not only to effectively control the disease but that would also facilitate trade thanks to the differentiation between vaccinated and infected animals.
During the meeting support was expressed for the development by the OIE of a worldwide surveillance network for increased knowledge of the zoosanitary situation of the disease. These initiatives will contribute to improving animal health control worldwide and preventing unjustified trade barriers.
The geographic distribution of the disease comprising the endemic areas of bluetongue, has traditionally been accepted to be between the latitudes of approximately 50°N and 35°S. There is now enough scientific evidence to accept its spread further north to 53°N.
No danger to humans
Bluetongue is an insect-borne viral disease to which all species of ruminants are susceptible. The disease poses no danger to human health.
It occurs mostly during periods of high temperature and rainfall and usually disappears with the first frost or cold weather, when midges stop their activity.
Globalisation, the change in weather patterns and the increase in speed and volume of international transport as well as passengers travel are known factors that could favour the spread of pathogens to new areas and the emergence of diseases.
Although the source of infection of this outbreak is still under investigation, the OIE highlights the importance of having effective Veterinary Services. The ability to early detect and respond rapidly to an unexpected event is dependent on the effectiveness of a national surveillance system and the transparency in reporting. In charge of this task in all countries worldwide, Veterinary Services are guarantors of animal health and animal welfare.