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Herpesviridae
The Herpesviridae are a large family of DNA viruses that cause diseases in animals, including humans.[1] [2] [3] The family name is derived from the Greek word herpein ("to creep"), referring to the latent, re-occurring infections typical of this group of viruses. Herpesviridae can cause latent or lytic infections.
Viral structureHerpes viruses all share a common structure—all herpes viruses are composed of relatively large double-stranded, linear DNA genomes encoding 100-200 genes encased within an icosahedral protein cage called the capsid which is itself wrapped in a lipid bilayer membrane called the envelope. This particle is known as the virion. Herpes virus life-cycleAll Herpes viruses are nuclear-replicating—the viral DNA is transcribed to RNA within the infected cell's nucleus. Infection is initiated when a viral particle contacts a cell with specific types of receptor molecules on the cell surface. Following binding of viral envelope glycoproteins to cell membrane receptors, the virion is internalized and dismantled, allowing viral DNA to migrate to the cell nucleus. Within the nucleus, replication of viral DNA and transcription of viral genes occurs. During symptomatic infection, infected cells transcribe lytic viral genes. In some host cells, a small number of viral genes termed latency associated transcript (LAT) accumulate instead. In this fashion the virus can persist in the cell (and thus the host) indefinitely. While primary infection is often accompanied by a self-limited period of clinical illness, long-term latency is symptom-free. Reactivation of latent viruses has been implicated in a number of diseases (e.g. Shingles). Following activation, transcription of viral genes transitions from latency-associated LAT to multiple lytic genes; these lead to enhanced replication and virus production. Often, lytic activation leads to cell death. Clinically, lytic activation is often accompanied by emergence of non-specific symptoms such as low grade fever, headache, sore throat, malaise, and rash as well as clinical signs such as swollen or tender lymph nodes and immunological findings such as reduced levels of natural killer cells. Human herpesviridae infectionsThere are eight distinct viruses in this family known to cause disease in humans.[4]
Zoonotic infectionsIn addition to the Herpes viruses considered endemic in humans, some viruses associated primarily with animals may infect humans. These are zoonotic infections:
Animal herpesviridaeIn animal virology the most important herpesviruses belong to the Alphaherpesvirinae. Research on pseudorabies virus (PrV), the causative agent of Aujeszky's disease in pigs, has pioneered animal disease control with genetically modified vaccines. PrV is now extensively studied as a model for basic processes during lytic herpesvirus infection, and for unravelling molecular mechanisms of herpesvirus neurotropism, whereas bovine herpesvirus 1, the causative agent of bovine infectious rhinotracheitis and pustular vulvovaginitis, is analyzed to elucidate molecular mechanisms of latency. The avian infectious laryngotracheitis virus is phylogenetically distant from these two viruses and serves to underline similarity and diversity within the Alphaherpesvirinae.[2] [3]
TaxonomyThe following genera are included here:
See alsoReferencesExternal links
cs:Herpes viry da:Herpesviridae de:Herpesviridae el:????????? es:Herpesviridae fr:Herpesviridae it:Herpesviridae nl:Herpesvirussen ja:????????? pl:Herpeswirusy pt:Herpes-vírus ro:Herpesviridae ru:???????????? sl:Herpesvirusi fi:Herpesvirukset sv:Herpesvirus zh:????? Source: Wikipedia | The above article is available under the GNU FDL. | Edit this article
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