Characterization of an Infectious Bronchitis Virus Isolated from Commercial Layers Suffering from False Layer...

Area of Science:

• Veterinary Virology
• Poultry Pathology
• Disease Epidemiology

Background:

• Infectious Bronchitis Virus (IBV) causes respiratory and reproductive issues in chickens.
• False Layer Syndrome (FLS) is a significant economic concern in commercial poultry, characterized by ovulation without egg laying.

Purpose of the Study:

• To characterize an IBV variant causing an FLS outbreak in Arizona.
• To evaluate the efficacy of a live-attenuated IBV vaccine protocol in reducing FLS incidence.
• To monitor the circulation of IBV strains in commercial flocks.

Main Methods:

• Isolation and characterization of a novel IBV variant (AZ/FLS/17).
• Challenge experiments comparing AZ/FLS/17 and M41 strains in SPF chicks.
• Implementation and monitoring of a live-attenuated IBV vaccine protocol.
• Molecular surveillance of IBV strains in different age groups.

Main Results:

• The novel IBV variant AZ/FLS/17 induced FLS.
• No significant differences in lesions or viral loads were observed between AZ/FLS/17 and M41 infections.
• The updated vaccine protocol led to a drastic reduction in FLS cases.
• IBV strain diversity increased with bird age.

Conclusions:

• The AZ/FLS/17 variant is associated with FLS in chickens.
• Live-attenuated IBV vaccines, including the Ma5 strain, are effective in controlling FLS.
• Ongoing molecular surveillance is crucial for managing IBV in commercial poultry populations.