Metapneumovirus
Encyclopedia
Human metapneumovirus (hMPV) is a negative single-stranded RNA
virus
of the family Paramyxoviridae and is closely related to the avian metapneumovirus (AMPV) subgroup C. It was isolated for the first time in 2001 in the Netherlands by using the RAP-PCR (RNA arbitrarily primed PCR) technique for identification of unknown viruses growing in cultured cells. It may be the second most common cause (after the respiratory syncytial virus) of lower respiratory infection in young children.
Compared with respiratory syncytial virus, infection with human metapneumovirus tends to occur in slightly older children and to produce disease that is less severe. Co-infection with both viruses can occur, and is generally associated with worse disease.
viruses during winter. Serologic studies have shown that by the age of five, virtually all children have been exposed to the virus and reinfections appear to be common. Human metapneumovirus may cause mild respiratory tract infection. However, small children, elderly and immunocompromised individuals are at risk of severe disease and hospitalization.
, NS1 and NS2, and the hMPV antisense RNA genome contains eight open reading frames in slightly different gene order than RSV (viz. 3’-N-P-M-F-M2-SH-G-L-5’). hMPV is genetically similar to the avian pneumoviruses A, B and in particular type C. Phylogenetic analysis of hMPV has demonstrated the existence of two main genetic lineages termed subtype A and B containing within them the subgroups A1/A2 and B1/B2 respectively.
-based approaches have been employed and these include:
has shown effectiveness in an animal model.
RNA
Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....
virus
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
of the family Paramyxoviridae and is closely related to the avian metapneumovirus (AMPV) subgroup C. It was isolated for the first time in 2001 in the Netherlands by using the RAP-PCR (RNA arbitrarily primed PCR) technique for identification of unknown viruses growing in cultured cells. It may be the second most common cause (after the respiratory syncytial virus) of lower respiratory infection in young children.
Compared with respiratory syncytial virus, infection with human metapneumovirus tends to occur in slightly older children and to produce disease that is less severe. Co-infection with both viruses can occur, and is generally associated with worse disease.
Epidemiology
Human metapneumovirus accounts for approximately 10% of respiratory tract infections that are not related to previously known etiologic agents. The virus seems to be distributed worldwide and to have a seasonal distribution with its incidence comparable to that for the influenzaInfluenza
Influenza, commonly referred to as the flu, is an infectious disease caused by RNA viruses of the family Orthomyxoviridae , that affects birds and mammals...
viruses during winter. Serologic studies have shown that by the age of five, virtually all children have been exposed to the virus and reinfections appear to be common. Human metapneumovirus may cause mild respiratory tract infection. However, small children, elderly and immunocompromised individuals are at risk of severe disease and hospitalization.
Genome
The genomic organisation of hMPV is analogous to RSV, however hMPV lacks the non-structural genesGênes
Gênes is the name of a département of the First French Empire in present Italy, named after the city of Genoa. It was formed in 1805, when Napoleon Bonaparte occupied the Republic of Genoa. Its capital was Genoa, and it was divided in the arrondissements of Genoa, Bobbio, Novi Ligure, Tortona and...
, NS1 and NS2, and the hMPV antisense RNA genome contains eight open reading frames in slightly different gene order than RSV (viz. 3’-N-P-M-F-M2-SH-G-L-5’). hMPV is genetically similar to the avian pneumoviruses A, B and in particular type C. Phylogenetic analysis of hMPV has demonstrated the existence of two main genetic lineages termed subtype A and B containing within them the subgroups A1/A2 and B1/B2 respectively.
Identification
The identification of hMPV has predominantly relied on reverse-transcriptase polymerase chain reaction (RT-PCR) technology to amplify directly from RNA extracted from respiratory specimens. Alternative more cost effective approaches to the detection of hMPV by nucleic acidNucleic acid
Nucleic acids are biological molecules essential for life, and include DNA and RNA . Together with proteins, nucleic acids make up the most important macromolecules; each is found in abundance in all living things, where they function in encoding, transmitting and expressing genetic information...
-based approaches have been employed and these include:
- 1) detection of hMPV antigens in nasopharyngeal secretions by immunofluorescent-antibody test
- 2) the use of immunofluorescence staining with monoclonal antibodiesMonoclonal antibodiesMonoclonal antibodies are monospecific antibodies that are the same because they are made by identical immune cells that are all clones of a unique parent cell....
to detect hMPV in nasopharyngeal secretions and shell vial cultures - 3) immunofluorescence assays for detection of hMPV-specific antibodies
- 4) the use of polyclonal antibodies and direct isolation in cultured cells.
Treatment
No treatment is yet known, but ribavirinRibavirin
Ribavirin is an anti-viral drug indicated for severe RSV infection , hepatitis C infection and other viral infections. Ribavirin is a prodrug, which when metabolised resembles purine RNA nucleotides...
has shown effectiveness in an animal model.