Submitted to: Virus Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 7, 1998
Publication Date: N/A
Interpretive Summary: Avian pneumoviruses cause a disease termed turkey rhinotracheitis. Before 1997 the U.S. was considered free of these viruses types which are found in Europe. However, during 1997 the USDA officially reported isolation of avian pneumoviruses from commercial turkeys in the U.S. Antibodies produced by infected turkeys in the U.S. did not react to diagnostic materials made from European avian pneumoviruses. This means the U.S. avian pneumoviruses are very different from their European counterparts. To further test this, a gene that encodes a highly conserved protein from the U.S. avian pneumovirus was analyzed. The gene from the two European avian pneumovirus subtypes was very closely related. However, the gene from the U.S. avian pneumovirus isolate was very different from the European viruses. This means avian pneumoviruses have emerged in the U.S. as a slightly different form compared to the European viruses. The genetic analysis agrees with the inability to initially detect presence of avian pneumovirus using antibodies from infected turkeys in the U.S.
Technical Abstract: Avian pneumovirus (APV) is the etiologic agent of turkey rhinotracheitis (TRT). In February, 1997 the National Veterinary Services Laboratory, Animal Plant Health Inspection Services of USDA reported the first official isolation of APV in the U.S. This is the first report of these virus types in the U.S. that was previously considered exotic to the U.S. and Canada. Degenerate oligonucleotide primers were used to amplify nucleotide sequences coding for the highly conserved matrix (M) protein gene. Although the type A and B European APV M genes share 75% identity in their coding sequences, they are only 60% similar to the U.S. APV/CO M protein gene. Predicted M proteins of European APV type A and B isolates share 89% identity in their amino acid sequence. However, the predicted M protein of APV/CO is only 78% similar to APV type A and 77% similar to APV type B protein sequences. Phylogenetically the U.S. APV/CO isolate separates as a unique virus relative to European APV type A and B strains that cluster together. Sequence information for the APV/CO M protein gene and predicted amino acids of the M protein confirm the unique nature of this isolate compared to its European counterparts. This correlates with the inability to serologically detect the U.S. APV/CO isolate using diagnostics based on European viruses.