The D1466 variant (also known as D212) of infectious bronchitis virus (IBV) has been only occasionally detected in Europe for more than 40 years since its first description in the late 1970s,. However, since 2006 increasing problems related to the D1466 genotype have been observed in most countries of western Europe. In Poland, major IBV epidemics recorded during the last 40 years have been caused by Mass, 793/B and recently QX types, whereas the viruses of the D1466 genotype have never been detected so far. Nevertheless, numerous clinical cases reported to the Department of Poultry Diseases at the National Veterinary Research Institute (Pulawy) from the field over a short recent period of time suggest that the epidemiological situation in the country has been changing rapidly. During seven months, between November 2011 and May 2012, eighteen outbreaks caused by D1466-like variants were identified in various chicken farms located far apart, in southwestern, northern and eastern Poland. Most cases concerned farms of layers and broiler breeders of different ages, in which production losses were recorded, but four cases were also detected in broiler farms. The nucleotide sequences of S1 spike gene fragments about 400 base pairs long of six Polish strains clustered together with the reference D1466 and V1397 variants, but they were different as their nucleotide identity was 86.2-99.5%, and they divided in two groups. This current epidemiological situation makes it necessary for veterinary services to consider new vaccination programmes to better protect susceptible poultry.
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