Highly Pathogenic Avian Influenza A Virus in Wild Migratory Birds, Qinghai Lake, China, 2022.

In July 2022, an outbreak of highly pathogenic avian influenza A(H5N1) virus clade 2.3.4.

Fusion Protein Cleavage Site Containing Three Basic Amino Acids Attenuates Newcastle Disease Virus in Chicken Embryos: Use as an Vaccine.

vaccination is an attractive immunization strategy for the poultry industry. However, although most live Newcastle disease virus (NDV) vaccine strains, such as LaSota and V4, can be used after hatching, they are pathogenic to chicken embryos when administered . We have previously reported that NDV strain TS09-C is a safe vaccine in specific-pathogen-free and commercial chicken embryos because it is attenuated in chicken embryos.

In-ovo Newcastle disease virus vaccine strain TS09-C protects commercial chickens against Newcastle disease in the presence of maternally derived antibodies.

Maternally derived antibodies (MDA) substantially interfere with active immunity in post-hatch vaccination, although they provide early protection against disease through passive immunity in young chickens. Previously, Newcastle disease virus (NDV) strain TS09-C was demonstrated to be safe and immunogenic as in-ovo vaccine in specific-pathogen-free chickens. Here, we evaluated the safety, protective efficacy, and duration of clinical protection of the TS09-C virus as an in-ovo vaccine for commercial chickens in the presence of Maternally derived antibodies against NDV.