Detection by reverse transcriptase-polymerase chain reaction and molecular characterization of subtype B avian metapneumovirus isolated in Brazil.

Abstract

Subtype B avian metapneumovirus (aMPV) was isolated and detected by reverse transcriptase-polymerase chain reaction (RT-PCR) in Brazilian commercial laying chicken flocks with no history of vaccination against aMPV and presenting respiratory signs and decreased egg production. RT-PCR results from samples from three affected flocks revealed that the three isolates were subtype B. Partial sequence analysis of the G glycoprotein gene confirmed that the samples belonged to subtype B and were not of the vaccine type. Comparison of nucleotide and amino acid sequences of the G gene of the three Brazilian aMPV samples with subtype B isolates from other countries revealed 95.1% to 96.1% identity. Nucleotide sequences showed 100% identity among the Brazilian subtype B samples and 95.6% identity with the subtype B vaccine strain used in Brazil. This work describes the circulation of subtype B aMPV in Brazil and discusses its importance in terms of disease epidemiology.