Pathogenesis of Venezuelan Equine Encephalomyelitis Virus Infections in the Developing Chick Embryo.

Although the Venezuelan equine encephalomyelitis virus is readily cultivable in the developing chick embryo (Beck and Wyckoff, 1938; Kubes and Rios, 1939; Gallo and Vogelsang, 1939), no studies appear to have been made on the rate of propagation or distribution of this virus in the embryo, as has been done by Higbie and Howitt (1935) and by Bang (1943) for the Eastern and Western equine viruses. Since the Venezuelan virus, aside from being immunologically different from the other two (Beck and Wyckoff, 1938; Kubes and Rios, 1939), differs from them in being more virulent for rabbits (Lennette and Koprowski, 1943) and for mice (Lennette and Koprowski, 1943) on inoculation by the intraperitoneal route, the pathogenesis of the infection produced by the Venezuelan virus in chick embryos was investigated to ascertain whether other biologic differences exist among these viruses.