[Brain teratology as a result of transplacental virus infection in ruminants].

Various viruses relating to congenital brain teratology in ruminants are discussed. These include: bluetongue which may be responsible for porencephaly and hydranencephaly; Akabane disease, Rift Valley fever (mouse brain attenuated virus) and Wesselsbron disease (wild-type and mouse brain attenuated viruses) which can give rise to porencephaly, hydranencephaly, micrencephaly and cerebellar hypoplasia, and bovine viral diarrhoea-mucosal disease which results only in cerebellar hypoplasia. Certain foetal, maternal and virological factors that might have an effect on the pathogenesis of viral teratogenesis are briefly reviewed. Mention is also made of the different diagnostic procedures that can be used such as, gross and histopathological examination, virus isolation and serology.