Persistence of infectious bronchitis virus (IBV) in farms with chickens immunized with Massachusetts vaccines alone or combined with 793B serotype.

Publication date: Aug 01, 2026

Infectious bronchitis virus (IBV) remains a major challenge for poultry production due to its genetic diversity and rapid evolution under vaccination pressure. This study evaluated how changes in vaccination strategy affect IBV lineage dynamics in commercial broiler farms using a sentinel-bird model. Six farms were monitored over 2 consecutive years. During the first survey (Y1), broilers were vaccinated with a combination of Massachusetts (GI-1) and 793B (GI-13) strains, whereas during the second survey (Y2) vaccination was restricted to Massachusetts alone. Non-vaccinated sentinel birds placed within vaccinated flocks were sampled at different time-points for IBV detection, genotyping, and serology. Overall IBV detection reached 65%, with GI-1, GI-13, and GI-16 lineages identified. In Y2, after withdrawal of the 793B vaccine, a significant expansion of the field strain GI-16 was observed (P

Concepts Keywords
Animals
Antibodies, Viral
Antibodies, Viral
broiler farm
Chickens
co-circulation
Coronavirus Infections
Genotype
Infectious bronchitis virus
Infectious bronchitis virus
Massachusetts
Poultry Diseases
sentinel chickens
Serogroup
Vaccination
vaccination
viral lineage dynamics
Viral Vaccines
Viral Vaccines
virus persistence

Semantics

Type Source Name
disease MESH bronchitis
disease MESH strains
disease MESH Mixed infections
disease MESH Coronavirus Infections
disease MESH Poultry Diseases

Original Article

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