When a BTV-infected midge takes a blood meal from a ruminant host, innoculated virus spreads from the skin to the regional lymph nodes. After initial replication in the lymph nodes, a cell-associated viraemia carries the virus to many tissues where further replication occurs in macrophages and endothelial cells. In the process of reproducing, bluetongue virus causes endothelial cell injury and necrosis<sup>9</sup>. In turn, an increase in vascular permeability causes oedema, and thrombosis can arise which may lead to tissue infarction. A consumptive coagulopathy can occure sheep and deer<sup>2</sup>. | When a BTV-infected midge takes a blood meal from a ruminant host, innoculated virus spreads from the skin to the regional lymph nodes. After initial replication in the lymph nodes, a cell-associated viraemia carries the virus to many tissues where further replication occurs in macrophages and endothelial cells. In the process of reproducing, bluetongue virus causes endothelial cell injury and necrosis<sup>9</sup>. In turn, an increase in vascular permeability causes oedema, and thrombosis can arise which may lead to tissue infarction. A consumptive coagulopathy can occure sheep and deer<sup>2</sup>. |