Submitted to: Virus Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/8/2002
Publication Date: 2/25/2003
Citation: Njenga, K.M., Lwamba, H.M., Seal, B.S. 2003. Metapneumoviruses in birds and humans: a review. Virus Research. Interpretive Summary: Prior to 1997 avian pneumoviruses were considered exotic to North America and during that year these viruses emerged in United States commercial turkeys. The virus caused upper respiratory disease in turkeys and was not detected using diagnostic reagents for avian pneumoviruses created in Europe available at that time. Subsequently, it was demonstrated that these viruses were genetically distinct from European viruses and were designated a unique avian pneumovirus sub-type. Since appearance of the Untied States avian pneumovirus a similar human pneumovirus was reported among people during 2001. Diagnostic evidence utilizing sera from humans lead to the thought that the human virus has been in the human population since 1950. Genetically the newly identified human pneumovirus is most closely related to the avian pneumovirus isolated among turkeys in the United States. Because the avian and new human pneumoviruses are generically distinct from other mammalian pneumoviruses they have been designated metapneumoviruses.
Technical Abstract: Avian pneumovirus (APV) and human metapneumovirus (hMPV) are newly emergent pathogens of turkeys and humans, respectively, that are associated with upper respiratory tract infections. Based on their different genomic organization and low level of nucleotide (nt) and amino acid (aa) identity with paramyxoviruses in the genus Pneumovirus, APV and hMPV have been classified into a new genus referred to as Metapneumovirus. First isolated during the1970s, APV strains have since been isolated in Europe, Africa, the Middle East, and United States. These viruses have been classified into four subgroups, APV/A, APV/B, APV/C, and APV/D based on nt and predicted aa sequence identity. Although it was first isolated in 2001, serological evidence indicates that hMPV may have been present in human population from as early as 1950s. There is only one subgroup of hMPV so far recognized, whose nt and aa sequence identity, indicates that it more closely related to APV/C isolates from the United States.