Abstract: The invention relates to a method for producing flu virus according to which: a) immunizing a hen by administering a flu vaccine to the hen, b) triggering embryogenesis in one or more eggs of the immunized hen, c) infecting the one or more embryonated eggs by inoculating a flu virus into the allantoic cavity of the eggs, d) incubating the one or more infected embryonated eggs under temperature and humidity conditions that allow replication of the virus, and e) harvesting the allantoic fluid of the one or more incubated eggs containing the virus.

Abstract: The live recombinant avian vaccine comprises, as vector, an avian herpesvirus comprising at least one nucleotide sequence coding for and expressing an antigenic polypeptide of an avian pathogenic agent, inserted into the region lying between the ATG of ORF UL55 and the junction of U.sub.L with the adjacent repeat region, under the control of the CMV immediate early promoter. The vector is preferably chosen from the group consisting of Marek's disease viruses (MDV and HVT), infectious laryngotracheitis virus ILTV and herpes of ducks. A polyvalent vaccine formula comprises at least two vaccines of this type, with different inserted sequences.

Abstract: The recombinant live avian vaccine comprises as vector an ILTV virus comprising and expressing at least one heterologous nucleotide sequence, this nucleotide sequence being inserted into the insertion locus formed by the intergenic region located between the stop codons of ORF B and ORF C of ILTV, which region, in a particular strain of ILTV, is defined between nucleotides 908 and 994 in SEQ ID NO:1.

Abstract: The live recombinant avian vaccine comprises, as vector, an avian herpesvirus comprising at least one nucleotide sequence coding for and expressing an antigenic polypeptide of an avian pathogenic agent, inserted into the region lying between the ATG of ORF UL55 and the junction of U.sub.L with the adjacent repeat region, under the control of the CMV immediate early promoter. The vector is preferably chosen from the group consisting of Marek's disease viruses (MDV and HVT), infectious laryngotracheitis virus ILTV and herpes of ducks. A polyvalent vaccine formula comprises at least two vaccines of this type, with different inserted sequences.

Abstract: The present invention relates to vaccines for avian use which are based on live recombinant avian herpesviruses, in particular the Marek's disease viruses including HVT virus (herpesvirus of turkey), in which has been inserted, by genetic recombination, at least one nucleotide sequence which encodes and expresses an antigenic polypeptide of an avian pathogen under conditions which ensure immunization leading to efficient protection of the vaccinated animal against the pathogen. In one embodiment, the antigenic polypeptide is inserted in the UL43 gene under the control of the CMV immediate early promoter. The vaccines of the present invention are advantageous over previously used vaccines in that they can be used to ensure total protection of animals against Gumboro disease and to immunize chicks as young as one-day old without secondary effects, and only require low doses.