Vaccination for fowl plague.

Area of Science:

• Veterinary Virology
• Avian Pathology
• Immunology

Background:

• Avian influenza viruses pose significant threats to poultry health and global food security.
• Fowl plague virus (FPV) is a highly virulent avian influenza strain.
• Understanding the pathogenicity and immunogenicity of different avian influenza strains is crucial for disease control.

Purpose of the Study:

• To investigate the pathogenicity and immunogenicity of Influenza A/turkey/Oregon/71 virus in chickens.
• To determine the transmission dynamics and host range of this avirulent strain.
• To assess if repeated passages in chickens alter the virus's virulence.

Main Methods:

• Intratracheal inoculation of chickens with Influenza A/turkey/Oregon/71 virus at various doses.
• Monitoring for clinical signs, antibody production, and viral shedding via tracheal swabs.
• Transmission studies involving contact controls.
• Serial passage of the virus in chickens for 10 generations.

Main Results:

• The virus was avirulent for chickens despite having antigenic characteristics of FPV.
• Inoculated chickens developed antibodies and immunity against fowl plague.
• Viral replication occurred, with recovery from tracheal swabs up to 4 days post-inoculation.
• Transmission to contact controls was observed only when cagemates were inoculated simultaneously, not 24 hours prior.
• The virus remained avirulent for chickens and turkeys after 10 serial passages.

Conclusions:

• Influenza A/turkey/Oregon/71 represents a potentially valuable tool for inducing immunity against fowl plague in chickens without causing disease.
• Early post-inoculation transmission is possible, highlighting the need for biosecurity measures.
• The virus's avirulence is stable through multiple passages in chickens, suggesting its suitability for vaccine development or experimental studies.