Human bocavirus

All other viruses and strains in species:Human bocavirus (HBoV) is the name given to all viruses in the genus Bocaparvovirus of virus family Parvoviridae that are known to infect humans. HBoV1 and HBoV3 (and gorilla bocaparvovirus) are members of species Primate bocaparvovirus 1 whereas viruses HBoV2 and HBoV4 belong to species Primate bocaparvovirus 2. Some of these viruses cause human disease. HBoV1 is strongly implicated in causing some cases of lower respiratory tract infection, especially in young children, and several of the viruses have been linked to gastroenteritis, although the full clinical role of this emerging infectious disease remains to be elucidated. Human bocavirus (HBoV) is the name given to all viruses in the genus Bocaparvovirus of virus family Parvoviridae that are known to infect humans. HBoV1 and HBoV3 (and gorilla bocaparvovirus) are members of species Primate bocaparvovirus 1 whereas viruses HBoV2 and HBoV4 belong to species Primate bocaparvovirus 2. Some of these viruses cause human disease. HBoV1 is strongly implicated in causing some cases of lower respiratory tract infection, especially in young children, and several of the viruses have been linked to gastroenteritis, although the full clinical role of this emerging infectious disease remains to be elucidated. Allander and colleagues at the Karolinska Institutet in Stockholm, Sweden, first cloned the coding sequence of this new member of the family of Parvoviridae in 2005 from pooled nasopharyngeal aspirates (NPA, collection of aspirated fluid from the back of the nasal cavity). They used a novel technique called molecular virus screening, based on random cloning and bioinformatical analysis. This technique has led to the discovery of new viruses such as polyomavirus KI (Karolinska Institute) and WU (Washington University), which are closely related to each other and have been isolated from respiratory secretions. Several groups of scientists have since then found that HBoV is the fourth most common virus in respiratory samples, behind rhinoviruses, respiratory syncytial virus and adenoviruses. The name bocavirus is derived from bovine and canine, referring to the two known hosts for the founder members of this genus; bovine parvovirus which infects cattle, and minute virus of canines which infects dogs. Parvoviruses (Latin: small viruses) have a 5 kilobase long single-stranded DNA, and they use some of their host's replication proteins to copy their DNA. The virons are small (diameter 18–26 nanometers), icosahedral and non enveloped. The capsid has T = 1 symmetry and consists of 60 copies of coat protein. The coat proteins have a conserved, eight stranded beta barrel motif that forms the core of the capsid. There is also a conserved alpha helix. The HBoV capsid shares three characteristic features also found in the other vertebrate parvoviruses: (1) a dimple like depression at each icosahedral 2-fold axis; (2) a large trimeric protrusion at or surrounding each 3-fold axis; (3) a cylindrical projection surrounding each 5-fold axis that encloses a central channel which connects the inside of the particle with its exterior and serves as the entry and exit portal for viral DNA. This 5-fold cylinder is itself encircled by a wide canyon like depression. While the dimple is also found among the invertebrate parvoviruses, they typically lack the 3-fold protrusions and canyon around the 5-fold channel. The external diameter of the capsid ranges from ∼21.5 nanometers (nm) at the lowest points of the dimple and canyon to ∼28 nm at the top of the protrusion. The genome is a linear, single-stranded DNA 5.5 kilobases in length with disparate terminal hairpin structures at each end.