Bluetongue Virus in wild ruminants in Europe: Concerns and facts, with a brief reference to bluetongue in cervids in Greece during the 2014 outbreak

Bluetongue is a constant threat to ruminants, affecting primarily the sheep industry. Bluetongue Virus, the causative agent, has a worldwide distribution and a large number of antigenically different serotypes (at least 26), with vector-borne transmission. All these make effective control measures difficult to implement. Expansion of the virus to Northern Europe changed the epidemiology of the disease and highlighted the existence of hitherto unknown vectors and susceptible hosts. A possible epidemiological role of wildlife as hosts of the virus must be considered, complicating the control strategies. In this review, facts regarding the disease in Europe and its impact in wildlife are presented; concerns are also discussed regarding implication of wild ruminants in surveillance of the disease and formulation of novel control strategies. Further, preliminary results of a study into the presence of Bluetongue Virus in cervids in Greece, performed during the outbreak currently (2014–15) prevailing in the country, have indicated (by using molecular techniques) presence of the virus in 3 of 19 samples from roe deer in areas adjoining domestic ruminant farms. It is concluded that wild ruminants should be included in surveillance programs and in strategies for controlling Bluetongue Virus infections in a region.