Plaque Size and Virulence of Attenuated Venezuelan Equine Encephalomyelitis Virus After Passage in Various Hosts
FORT DETRICK FREDERICK MD
Pagination or Media Count:
The virulence and plaque properties of a new, small plaque attenuated 20t strain of Venezuelan equine encephalomyelitis VEE virus were characterized and compared with those of the moderately attenuated small plaque 9t and the virulent, large plaque parent egg seed strains in a variety of hosts. At large plaque, attenuated viral type was isolated from the small plaque 20t strain by passage in embryonated eggs and a small plaque, virulent strain was isolated by passage in mice. Thus, while plaque size and virulence were shown not to be irrevocably linked for VEE virus, the data provide evidence that deliberate selection and passage in specific laboratory host systems can produce stable viral types whose plaque size and virulence characteristics are correlated.