The Pathology and Pathogenesis of Bluetongue

Bluetongue vaccination in Europe

“…Adverse responses to MLV vaccination can include depressed milk production in lactating sheep, and abortion/embryonic death and teratogenesis in offspring when these vaccines are used in pregnant females [2,16,21,101]. Another risk associated with the use of MLVs derived from their potential of infecting vectors with possible reversion to virulence and/or reassortment of MLV genes with those of wild-type virus strains.…”

“…Although instances of reassortment have been documented in Europe [22], the frequency and significance of these events remain uncertain. Natural dissemination of MLV strains of BTV is also probably responsible for the sporadic incidence of teratogenic defects in unvaccinated cattle in South Africa and North America [2]. Finally, as MLV-vaccinated animals are not sero logically discernible from naturally infected animals, the use of MLVs precludes the possibility of developing a DIVA strategy [10,16].…”

“…Bluetongue virus (BTV) is the cause of bluetongue (BT), an insect-transmitted disease of domestic and wild ruminants [1,2]. BTV infection occurs throughout many of the temperate and tropical regions of the world, coincident with the distribution of specific species of Culicoides biting midges that act as biological vectors of the virus [3,4].…”

Retrospective Analysis of the Bluetongue Outbreak in Serbia

“…Bluetongue (Febris catarrhalis ovium) is a noncontiguous vector-borne viral disease of domestic and wild ruminants with a wide distribution and considerable impact on the health status and production (1,2). The disease is caused by the Bluetongue Virus (BTV), a double stranded RNA virus of the Orbivirus genus in the Reoviridae family (3,4).…”

“…In endemic regions the disease displays a seasonal pattern, with highest incidence in late summer when the vector population reaches its peak (8). The severity of clinical symptoms depends mainly on the infected host, the virulence of the BTV strain and the immunological status of the affected animals (2,3). The clinical form of bluetongue is most commonly observed in domestic sheep, and it is characterised by fever, excessive salivation, hyperaemia of the nasal and labial mucous membranes, oedema and swelling of the face, severe dyspnoea, asphyxia, oedemas and a blue swollen tongue partly hanging out of the mouth (9,10,11).…”