 The incorrect assumption that the virus was isolated from human infectious material is still reported by Encyclopædia Britannica and by ATCC in the description of the history of the viral isolate Sendai/52.It was also believed that the virus could cause disease not only in humans but also in pigs, because antibodies to the virus were often found in their organisms during the swine epidemic in Japan in 1953–1956.High incidence of seropositivity to the virus was observed in pigs in 15 districts of Japan.