Sequence analysis of the nucleocapsid and phosphoprotein genes of avian pneumoviruses circulating in the US

Avian pneumovirus (APV) has recently been described as the cause of a new r espiratory syndrome in turkey flocks in the United States. We here describe the complete sequence of the nucleocapsid (N) and phosphoprotein (P) genes of this emerging APV (APV/US). Our results show 59 and 61% nucleotide sequ ence identity of the APV/US N gene with N genes of previously described Eur opean APV subgroups A and B, respectively. The P gene of APV/US showed only 53% nucleotide sequence identity with the ortholog from APV subgroup A. Ph ylogenetic analyses of both N and P genes clearly demonstrate that the APV/ US lineage is evolutionarily related but distinct from European APVs. Moreo ver, sequence analysis of the N and P genes from two laboratory adapted iso lates of APV/US (APV/MN-1a and APV/MN-1b) and from ten clinical samples fro m APV-infected turkeys suggests only modest level of amino acid divergence in the N (0-0.3%) and P (0-1.4%) proteins. Taken together, the results of t his study indicate that APV/US represents a new subgroup (subgroup Q of APV and show that there is limited heterogeneity in the N and P genes of APV/U S isolates. (C) 2001 Elsevier Science B.V. All rights reserved.