| antigenic and s-1 genomic characterization of the delaware variant serotype of infectious bronchitis virus. | a previously unrecognized infectious bronchitis virus (ibv) serotype, referred to hereafter as the delaware variant (de var), was isolated from commercial broiler chickens during a severe, widespread respiratory disease epornitic in the delmarva peninsula region of the united states in january-march 1992. the de var serotype was found to be antigenically unrelated by virus-neutralization (vn) test to nine reference ibv serotypes from north america. additional vn tests indicated that the de var i ... | 1997 | 9356713 |