Abstract: Disclosed is a temperature - sensitive (ts) mutant of bovine viral diarrhoea (BVD) virus which shows a considerably limited replication ability at the animal body temperature. The mutant is prepared by reacting wild-type BVD with a chemical mutagen such as nitrous acid. The mutant virous is advantageously used in vaccine compositions because it is capable of inducing immunity in bovines without causing serious side effects.

Abstract: A live bovine viral diarrhoea (BVD) virus vaccine capable of producing immunity in bovines without causing significant side effects comprising a temperature sensitive (ts) mutant of BVD virus which is obtained by mutating a strain of BVD virus with nitrous acid. The temperature sensitive mutants show a replication ability considerably limited at the animal body temperature of 39.5.degree. C. The vaccine may be combined with other live bovine vaccines such as respiratory virus vaccines and then administered to bovines.

Abstract: The invention relates to a novel influenza virus strain and to the influenza virus vaccine containing said strain.The new strain, which is the CNCM N.degree. I-099 strain, is prepared by recombination of the influenza A/PR/8/34 virus strain with the influenza A/California/10/78 (CNCM N.degree. I-098) virus strain.The vaccine is prepared by allowing the CNCM N.degree. I-099 strain to grow in the allantoic cavity of fertile hen's eggs, harvesting and freeze-drying the yielded virus material.The strain and the vaccine deriving therefrom are valuable for the immunization against influenza caused by influenza type A (H.sub.1 N.sub.1) virus strains.

Abstract: The invention relates to a novel influenza virus strain and to the influenza virus vaccine containing said strain.The new strain, which is the CNCM I-062 strain, is prepared by recombination of the influenza A/PR/8/34 virus strain with the influenza A/Alaska/5/77 virus strain.The vaccine is prepared by allowing the CNCM I-062 strain to grow in the allantoic cavity of fertile hen's eggs, harvesting and freeze-drying the yielded virus material.The strain and the vaccine deriving therefrom are valuable for the immunization against influenza caused by influenza type A (H.sub.3 N.sub.2) virus strains.

Abstract: The invention relates to a novel influenza virus strain and to the influenza virus vaccine containing said strain.The new strain, which is the DNCM No. I-099 strain, is prepared by recombination of the influenza A/PR/8/34 virus strain with the influenza A/California/10/78 (CNCM No. I-098) virus strain.The vaccine is prepared by allowing the CNCM No. I-099 strain to grow in the allantoic cavity of fertile hen's eggs, harvesting and freeze-drying the yielded virus material.The strain and the vaccine deriving therefrom are valuable for the immunization against influenza caused by influenza type A (H.sub.1 N.sub.1) virus strains.

Abstract: Attenuated stable influenza type B virus strains are obtained by recombining a vaccinal and previously attenuated influenza type B virus strain with an influenza type B virus isolate having the desired serotype and isolating a recombinant having at least one marker property of the attenuated parent strain which is not shared by the other parent strain and the antigenic composition of the other parent strain. The obtained strains are useful for the production of nasal influenza vaccines.