The emergence and nature of different strains of infectious bronchitis virus (IBV) in Europe are described. Infectious bronchitis (IB) is the most important endemic viral respiratory disease where highly pathogenic Newcastle disease and avian influenza are not present. IB was first described in the UK in 1948 and identified as Massachusetts type. In the 1970s and 80s new serotypes were reported in Holland and elsewhere and new vaccines were developed. The 1990s saw the emergence of the major variant commonly called 793B, again needing a new vaccine. Two novel types have been recognised since 2000, Italy 02 and QX. Italy 02 appears to be well controlled by the use of two different live vaccines (H120 and the 793B-related 4/91) while for QX, associated with nephritis in young birds and silent layers, new vaccines are in development. The use of two vaccines as above is a widely used protocol and is capable of protecting against a wide range of different types. Alternative approaches to IB vaccination are discussed. The importance of constant surveillance for prevalent and novel IBV types is emphasised and the value of experimental infections in chickens to determine the pathogenesis and pathology of new types in addition to testing efficacy of vaccines is outlined.
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