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→Vaccination
===Vaccination===
===Vaccination===
Vaccines against bluetongue are available. Vaccination typically is used to prevent outbreaks of BT, and has also been used in an effort to control incursions of BTV. Only modified live BTV vaccines are in widespread use, particularly in Africa, the United States and, most recently, southern Europe. These vaccines have proven very useful in preventing losses attributable to BT, but they also suffer from a number of serious potential deficiencies that include: the introduction of novel virus strains into the environment, perhaps leading to infection of vector insects; quasispecies evolution with possible reversion to virulence or creation of new strains of BTV; reassortment of gene segments with indigenous viruses to generate potentially novel recombinants; fetal infection and teratogenesis. In fact, it is increasingly clear that only strains of BTV that have been modified by growth in cell culture, such as MLV vaccine strains, have the capacity to cross the ruminant placenta. Once MLV BTV strains cross the placenta they cause embryonic or fetal death, and cerebral malformations after infection of older fetuses that survive congenital infection [4,19,24]. New generation vaccines, such as the virus-like particles produced by baculovirus expression of different viral proteins [27], have not yet been used extensively perhaps because of their cost.
===Vector Control===
===Vector Control===