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Betaherpesviruses
''Betaherpesvirinae'' is a subfamily of viruses in the order '' Herpesvirales'' and in the family '' Herpesviridae''. Mammals serve as natural hosts. There are 26 species in this subfamily, divided among 5 genera. Diseases associated with this subfamily include: human cytomegalovirus (HHV-5): congenital CMV infection; HHV-6: 'sixth disease' (also known as ''roseola infantum'' or ''exanthem subitum''); HHV-7: symptoms analogous to the 'sixth disease'. Genera ''Betaherpesvirinae'' consists of the following five genera: * ''Cytomegalovirus'' * '' Muromegalovirus'' * ''Proboscivirus'' * ''Quwivirus'' * ''Roseolovirus'' Structure Viruses in ''Betaherpesvirinae'' are enveloped, with icosahedral, spherical to pleomorphic, and Round geometries, and T=16 symmetry. The diameter is around 150-200 nm. Genomes are linear and non-segmented, around 140-240kb in length. Life cycle Viral replication is nuclear, and is lysogenic. Entry into the host cell is achieved by attachment ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Herpesvirus 6
Human herpesvirus 6 (HHV-6) is the common collective name for ''human betaherpesvirus 6A'' (HHV-6A) and ''human betaherpesvirus 6B'' (HHV-6B). These closely related viruses are two of the nine known herpesviruses that have humans as their primary host. HHV-6A and HHV-6B are double-stranded DNA viruses within the ''Betaherpesvirinae'' subfamily and of the genus ''Roseolovirus''. HHV-6A and HHV-6B infect almost all of the human populations that have been tested. HHV-6A has been described as more neurovirulent, and as such is more frequently found in patients with neuroinflammatory diseases such as multiple sclerosis. HHV-6 (and HHV-7) levels in the brain are also elevated in people with Alzheimer's disease. HHV-6B primary infection is the cause of the common childhood illness exanthema subitum (also known as roseola infantum or sixth disease). It is passed on from child to child. It is uncommon for adults to contract this disease as most people have had it by kindergarten, and on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Herpesvirus 7
''Human betaherpesvirus 7'' (HHV-7) is one of nine known members of the ''Herpesviridae'' family that infects humans. HHV-7 is a member of ''Betaherpesvirinae'', a subfamily of the ''Herpesviridae'' that also includes HHV-6 and ''Cytomegalovirus'' (HHV-5 or HCMV). HHV-7 often acts together with HHV-6, and the viruses together are sometimes referred to by their genus, ''Roseolovirus''. HHV-7 was first isolated in 1990 from CD4+ T cells taken from peripheral blood lymphocytes. Signs and symptoms Both HHV-6B and HHV-7, as well as other viruses, can cause a skin condition in infants known as exanthema subitum, although HHV-7 causes the disease less frequently than HHV-6B. HHV-7 infection also leads to or is associated with a number of other symptoms, including acute febrile respiratory disease, fever, rash, vomiting, diarrhea, low lymphocyte counts, and febrile seizures, though most often no symptoms present at all. There are indications that HHV-7 can contribute to the developm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viruses
A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Since Dmitri Ivanovsky's 1892 article describing a non-bacterial pathogen infecting tobacco plants and the discovery of the tobacco mosaic virus by Martinus Beijerinck in 1898,Dimmock p. 4 more than 9,000 virus species have been described in detail of the millions of types of viruses in the environment. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. The study of viruses is known as virology, a subspeciality of microbiology. When infected, a host cell is often forced to rapidly produce thousands of copies of the original virus. When not inside an infected cell or in the process of infecting a cell, viruses exist in the form of independent particles, or ''virions'', consisting of (i) the genetic material, i.e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neuron
A neuron, neurone, or nerve cell is an electrically excitable cell that communicates with other cells via specialized connections called synapses. The neuron is the main component of nervous tissue in all animals except sponges and placozoa. Non-animals like plants and fungi do not have nerve cells. Neurons are typically classified into three types based on their function. Sensory neurons respond to stimuli such as touch, sound, or light that affect the cells of the sensory organs, and they send signals to the spinal cord or brain. Motor neurons receive signals from the brain and spinal cord to control everything from muscle contractions to glandular output. Interneurons connect neurons to other neurons within the same region of the brain or spinal cord. When multiple neurons are connected together, they form what is called a neural circuit. A typical neuron consists of a cell body (soma), dendrites, and a single axon. The soma is a compact structure, and the axon and dend ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exanthema Subitum
Roseola, also known as sixth disease, is an infectious disease caused by certain types of human herpes viruses. Most infections occur before the age of three. Symptoms vary from absent to the classic presentation of a fever of rapid onset followed by a rash. The fever generally lasts for three to five days, while the rash is generally pink and lasts for less than three days. Complications may include febrile seizures, with serious complications being rare. It is caused by ''human herpesvirus 6'' (HHV-6A, HHV-6B) or ''human herpesvirus 7'' (HHV-7). Spread is usually through the saliva of those who are otherwise healthy. However, it may also spread from the mother to baby during pregnancy. Diagnosis is typically based on symptoms and does not need to be confirmed with blood tests (PCR or antigen). Low numbers of white blood cells may also be present. Treatment includes sufficient fluids and medications to treat the fever. Nearly all people are infected at some point in time. Ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multiple Sclerosis
Multiple (cerebral) sclerosis (MS), also known as encephalomyelitis disseminata or disseminated sclerosis, is the most common demyelinating disease, in which the insulating covers of nerve cells in the brain and spinal cord are damaged. This damage disrupts the ability of parts of the nervous system to transmit signals, resulting in a range of signs and symptoms, including physical, mental, and sometimes psychiatric problems. Specific symptoms can include double vision, blindness in one eye, muscle weakness, and trouble with sensation or coordination. MS takes several forms, with new symptoms either occurring in isolated attacks (relapsing forms) or building up over time (progressive forms). In the relapsing forms of MS, between attacks, symptoms may disappear completely, although some permanent neurological problems often remain, especially as the disease advances. While the cause is unclear, the underlying mechanism is thought to be either destruction by the immune system ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Cytomegalovirus
''Human betaherpesvirus 5'', also called human cytomegalovirus (HCMV), is species of virus in the genus ''Cytomegalovirus'', which in turn is a member of the viral family known as ''Herpesviridae'' or herpesviruses. It is also commonly called CMV. Within ''Herpesviridae'', HCMV belongs to the ''Betaherpesvirinae'' subfamily, which also includes cytomegaloviruses from other mammals. CMV is a double-stranded DNA virus. Although they may be found throughout the body, HCMV infections are frequently associated with the salivary glands. HCMV infection is typically unnoticed in healthy people, but can be life-threatening for the immunocompromised, such as HIV-infected persons, organ transplant recipients, or newborn infants. Congenital cytomegalovirus infection can lead to significant morbidity and even death. After infection, HCMV remains latent within the body throughout life and can be reactivated at any time. Eventually, it may cause mucoepidermoid carcinoma and possibly other m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
B-cell
B cells, also known as B lymphocytes, are a type of white blood cell of the lymphocyte subtype. They function in the humoral immunity component of the adaptive immune system. B cells produce antibody molecules which may be either secreted or inserted into the plasma membrane where they serve as a part of B-cell receptors. When a naïve or memory B cell is activated by an antigen, it proliferates and differentiates into an antibody-secreting effector cell, known as a plasmablast or plasma cell. Additionally, B cells present antigens (they are also classified as professional antigen-presenting cells (APCs)) and secrete cytokines. In mammals, B cells mature in the bone marrow, which is at the core of most bones. In birds, B cells mature in the bursa of Fabricius, a lymphoid organ where they were first discovered by Chang and Glick, which is why the 'B' stands for bursa and not bone marrow as commonly believed. B cells, unlike the other two classes of lymphocytes, T cells a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Immune System
The immune system is a network of biological processes that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as cancer cells and objects such as wood splinters, distinguishing them from the organism's own healthy tissue. Many species have two major subsystems of the immune system. The innate immune system provides a preconfigured response to broad groups of situations and stimuli. The adaptive immune system provides a tailored response to each stimulus by learning to recognize molecules it has previously encountered. Both use molecules and cells to perform their functions. Nearly all organisms have some kind of immune system. Bacteria have a rudimentary immune system in the form of enzymes that protect against virus infections. Other basic immune mechanisms evolved in ancient plants and animals and remain in their modern descendants. These mechanisms include phagocytosis, antimicrobial pe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gammaherpesvirinae
''Gammaherpesvirinae'' is a subfamily of viruses in the order ''Herpesvirales'' and in the family ''Herpesviridae''. Viruses in ''Gammaherpesvirinae'' are distinguished by reproducing at a more variable rate than other subfamilies of ''Herpesviridae''. Mammals serve as natural hosts. There are 43 species in this subfamily, divided among 7 genera with three species unassigned to a genus. Diseases associated with this subfamily include: HHV-4: infectious mononucleosis. HHV-8: Kaposi's sarcoma. Taxonomy Herpesviruses represent a group of double-stranded DNA viruses distributed widely within the animal kingdom. The family ''Herpesviridae'', which contains eight viruses that infect humans, is the most extensively studied group within this order and comprises three subfamilies, namely ''Alphaherpesvirinae'', ''Betaherpesvirinae'' and ''Gammaherpesvirinae''. Within the ''Gammaherpesvirinae'' there are a number of unclassified viruses including ''Cynomys herpesvirus 1'' (CynGHV-1)Nag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alphaherpesvirinae
''Alphaherpesvirinae'' is a subfamily of viruses in the family ''Herpesviridae'', primarily distinguished by reproducing more quickly than other subfamilies in the ''Herpesviridae''. In animal virology the most important herpesviruses belong to the Alphaherpesvirinae. Pseudorabies virus is the causative agent of Aujeszky's disease in pigs and ''Bovine herpesvirus 1'' is the causative agent of bovine infectious rhinotracheitis and pustular vulvovaginitis. Mammals serve as natural hosts. There are currently 45 species in this subfamily, divided among 5 genera with one species unassigned to a genus. Diseases associated with this subfamily include: HHV-1 and HHV-2: skin vesicles or mucosal ulcers, rarely encephalitis and meningitis, HHV-3: chickenpox (varicella) and shingles, GaHV-2: Marek's disease. Genera ''Alphaherpesvirinae'' consists of the following five genera: * ''Iltovirus'' * ''Mardivirus'' * ''Scutavirus'' * ''Simplexvirus'' * ''Varicellovirus'' The species ''Chelo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Herpesvirales
The ''Herpesvirales'' is an order of dsDNA viruses (Baltimore group I) with animal hosts, characterised by a common morphology consisting of an icosahedral capsid enclosed in a glycoprotein-containing lipid envelope. Common infections in humans caused by members of this order include cold sores, genital herpes, chickenpox, shingles, and glandular fever. ''Herpesvirales'' is the sole order in the class ''Herviviricetes'', which is the sole class in the phylum ''Peploviricota''. Virology Morphology All members of the order have a virion structure that consists of a DNA core surrounded by an icosahedral capsid composed of 12 pentavalent and 150 hexavalent capsomeres (T = 16). The capsid has a diameter of ~110 nanometers (nm) and is embedded in a proteinaceous matrix called the tegument, which in its turn is enclosed by a glycoprotein-containing lipid envelope with a diameter of about 200 nm. The DNA genome is linear and double stranded, with sizes in the range 125–290 kb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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