In Spain, the Infectious Bronchitis Virus (IBV) has always been the major respiratory concern in broilers. However, more and more frequently, circulation of Avian Metapneumoviurs (aMPV) is also seen on broiler farms in Spain, irrespective of whether they are located in risky areas (multi-age poultry areas) or areas where aMPV circulation is not suspected (absence of turkeys or long cycle birds.

The objective of this study was to evaluate the synergy between IBV and aMPV in different areas and seasons on broiler farms in Spain with different vaccination programmes.