Molecular epidemiology of avian pneumovirus strains in Italy

Avian Pneumovirus (APV) infection in Italy is reported from its first appearance in 1987 to present day. The B type virus has been found in different geographical regions but more recently, A type virus has also been detected. To establish the identity and heterogeneity among the APV strains that circulated in Italy, the nucleotide sequences of the Fusion (F) gene were determined and compared with European APV field strains and commonly available vaccine strains. Six B type and one A type Avian Pneumovirus strains isolated in Italy from 1987 to 2004, were grown in chicken embryo tracheal organ cultures (TOC). RNA was extracted from TOC medium and three overlapping RT-PCRs, covering the entire F gene, were performed for further sequencing of the strains. Phylograms for the ~1600 bp sequence were constructed with the MEGA package, version 3.1. As expected, the 6 B type isolates were clustered with the previously published European APV B sequences. Within the group, significant sub clustering was apparent, as the more recent isolates (2001-2004) formed one cluster clearly separated from viruses isolated in the former decade (100% bootstrap).