Surveillance of influenza A viruses in wild birds in Slovenia from 2006 to 2010.

Within the framework of the surveillance program for the early detection of H5 and H7 subtypes of avian influenza (AI) viruses, samples from 2547 wild birds of different species that were collected between 2006 and 2010 were examined by PCR-based methods. AI viruses of various subtypes were detected in 4.4% of birds from four different orders: Anseriformes, Ciconiiformes, Charadriiformes, and Pelecaniformes. Highly pathogenic avian influenza (HPAI) H5N1 viruses were detected only in 2006. HPAI H5N1 virus was confirmed in 1.9% of birds from four different species. Comparison of nucleotide sequences of the H5N1 hemagglutinin gene indicated that two different HPAI H5N1 viruses from the European-Middle Eastern-African clade 1 had been introduced into Slovenia, despite the relatively short duration of the HPAI outbreak. Low pathogenic avian influenza (LPAI) viruses were detected in 2.5% of birds during a 5-yr period. The subtypes H1, H2, H3, H4, H5, H7N7, H8, H10, H11, and H13N6 were determined in 18 out of 64 cases. The highest prevalence (81%) of LPAI viruses, including the H5 subtype, were found in birds sampled as a part of the "active" surveillance system.