A surveillance network for viral disease
BT and AHS are viral diseases transmitted by vector insects (Culicoides genus) and affect horses, and domestic and wild ruminants. Disease outbreaks over the past decade in northern Europe are a serious cause for alert and present a significant health hazard for livestock. To make matters worse, novel virus serotypes have emerged from Asia and their cross-boundary transport causes major concern due to the lack of appropriate vaccines. As a result, it is now accepted that countries ought to implement surveillance networks for detecting and managing these viral diseases. To this end, the EU-funded MED_REO_NET project was designed to develop surveillance mechanisms and expand our knowledge of the epidemiology of BT, AHS and epizootic haemorrhagic disease in the Mediterranean Basin and Europe. After assessing the protocols in place for surveillance, virus strain identification and vaccination strategies, project partners devised a series of improvement recommendations. They tested various insecticides and different devices for sampling insects under different climatic conditions, and developed molecular assays for correct insect identification and taxonomy classification. A web-based collection of morphological features also contributed to the correct insect identification. Regional studies on insect distribution and abundance in relation to the climatic variables in Europe helped establish risk models of infection. By reviewing the vector breeding sites in Europe, it was also possible for researchers to estimate the probability of vector occurrence in a particular region and, thereby, risk of disease transmission. Furthermore, a database with sequencing information of BT virus strains also contributed to virus identification during screening. The MED_REO_NET initiative provided important insight into the epidemiology of BT and AHS diseases, providing a framework for interactions between research institutions and national veterinary services. Implementation of the project recommendations and screening assays is expected to constrain disease transmission in Europe.
