Detection and molecular characterization of infectious bronchitis-like viruses in wild bird populations.

We examined 884 wild birds mainly from the Anseriformes, Charadriiformes and Galliformes orders for infectious bronchitis (IBV)-like coronavirus in Poland between 2008 and 2011. Coronavirus was detected in 31 (3.5%) of the tested birds, with detection rates of 3.5% in Anseriformes and 2.3% in Charadriiformes and as high as 17.6% in Galliformes. From the 31 positive samples, only 10 gave positive results in molecular tests aimed at various IBV genome fragments: five samples were positive for the RdRp gene, four for gene 3, eight for gene N and eight for the 3'-untranslated region fragment. All analysed genome fragments of the coronavirus strains shared different evolutionary branches, resulting in a different phylogenetic tree topology. Most detected fragment genes seem to be IBV-like genes of the most frequently detected lineages of IBV in this geographical region (i.e. Massachusetts, 793B and QX). Two waves of coronavirus infections were identified: one in spring (April and May) and another in late autumn (October to December). To our knowledge this is the first report of the detection of different fragment IBV-like genes in wild bird populations.