[Morphological study of a mixed alphavirus infection].

In combined paired cultivation of 8 Venezuelan equine encephalomyelitis virus, multiploid virions formed in 17.8% of cases. Five clones with this effect were used in mixed infections with clones of Semliki Forest and Sindbis viruses. In these infections changes in virions of the virus progeny were observed in 20% and 16.6%, respectively. Mixed cultivation of pairs of Sindbis and Semliki Forest viruses resulted in formation of multiploid virions in 42.8%. Besides, in two mixed populations formed upon combined multiplication of the latter viruses virions of unusual shapes were found: rounded, oval, elongated, and triangular designated as polymorphic.