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Pathogenic Viruses
A viral disease (or viral infection) occurs when an organism's body is invaded by pathogenic viruses, and infectious virus particles (virions) attach to and enter susceptible cells. Examples include the common cold, gastroenteritis, COVID-19, the flu, and rabies. Structural characteristics Basic structural characteristics, such as genome type, virion shape and replication site, generally share the same features among virus species within the same family. * Double-stranded DNA families: three are non-enveloped (''Adenoviridae'', ''Papillomaviridae'' and ''Polyomaviridae'') and two are enveloped (''Herpesviridae'' and ''Poxviridae''). All of the non-enveloped families have icosahedral capsids. * Partly double-stranded DNA viruses: ''Hepadnaviridae''. These viruses are enveloped. * One family of single-stranded DNA viruses infects humans: ''Parvoviridae''. These viruses are non-enveloped. * Positive single-stranded RNA families: three non-enveloped ('' Astroviridae'', ''Calicivi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infectious Disease (medical Specialty)
Infectious diseases (ID), also known as infectiology, is a medical specialty dealing with the diagnosis and treatment of infections. An infectious diseases specialist's practice consists of managing nosocomial (Hospital-acquired infection, healthcare-acquired) infections or community-acquired infections. An ID specialist investigates and determines the cause of a disease (bacteria, virus, parasite, fungus or prions). Once the cause is known, an ID specialist can then run various tests to determine the best drug to treat the disease. While infectious diseases have always been around, the infectious disease specialty did not exist until the late 1900s after scientists and physicians in the 19th century paved the way with research on the sources of infectious disease and the development of vaccines. Scope Infectious diseases specialists typically serve as consultants to other physicians in cases of complex infections, and often manage patients with HIV/AIDS and other forms of immuno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Capsids
A capsid is the protein shell of a virus, enclosing its genetic material. It consists of several oligomeric (repeating) structural subunits made of protein called Protomer (structural biology), protomers. The observable 3-dimensional morphological subunits, which may or may not correspond to individual proteins, are called capsomeres. The proteins making up the capsid are called capsid proteins or viral coat proteins (VCP). The virus genomic component inside the capsid, along with occasionally present virus core protein, is called the virus core. The capsid and core together are referred to as a nucleocapsid (cf. also virion). Capsids are broadly classified according to their structure. The majority of the viruses have capsids with either Helix, helical or icosahedral structure. Some viruses, such as bacteriophages, have developed more complicated structures due to constraints of elasticity and electrostatics. The icosahedral shape, which has 20 equilateral triangular faces, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Capsid
A capsid is the protein shell of a virus, enclosing its genetic material. It consists of several oligomeric (repeating) structural subunits made of protein called protomers. The observable 3-dimensional morphological subunits, which may or may not correspond to individual proteins, are called capsomeres. The proteins making up the capsid are called capsid proteins or viral coat proteins (VCP). The virus genomic component inside the capsid, along with occasionally present virus core protein, is called the virus core. The capsid and core together are referred to as a nucleocapsid (cf. also virion). Capsids are broadly classified according to their structure. The majority of the viruses have capsids with either helical or icosahedral structure. Some viruses, such as bacteriophages, have developed more complicated structures due to constraints of elasticity and electrostatics. The icosahedral shape, which has 20 equilateral triangular faces, approximates a sphere, while th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retroviridae
A retrovirus is a type of virus that inserts a DNA copy of its RNA genome into the DNA of a host cell that it invades, thus changing the genome of that cell. After invading a host cell's cytoplasm, the virus uses its own reverse transcriptase enzyme to produce DNA from its RNA genome, the reverse of the usual pattern, thus ''retro'' (backward). The new DNA is then incorporated into the host cell genome by an integrase enzyme, at which point the retroviral DNA is referred to as a provirus. The host cell then treats the viral DNA as part of its own genome, transcribing and translating the viral genes along with the cell's own genes, producing the proteins required to assemble new copies of the virus. Many retroviruses cause serious diseases in humans, other mammals, and birds. Retroviruses have many subfamilies in three basic groups. * Oncoretroviruses (cancer-causing retroviruses) include human T-lymphotropic virus (HTLV) causing a type of leukemia in humans, and murine le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flaviviridae
''Flaviviridae'' is a family of Viral envelope, enveloped positive-strand RNA viruses which mainly infect mammals and birds. They are primarily spread through arthropod vector (epidemiology), vectors (mainly ticks and mosquitoes). The family gets its name from the yellow fever virus; ''flavus'' is Latin for "yellow", and yellow fever in turn was named because of its propensity to cause jaundice in victims. There are 89 species in the family divided among four genera. Diseases associated with the group include: hepatitis (hepaciviruses), Bleeding, hemorrhagic syndromes, Bovine viral diarrhea, fatal mucosal disease (pestiviruses), Viral hemorrhagic fever, hemorrhagic fever, encephalitis, and the birth defect microcephaly (flaviviruses). Structure Virus particles are enveloped and spherical with icosahedral-like geometries that have pseudo T=3 symmetry. They are about 40–60 nanometer, nm in diameter. Genome Members of the family ''Flaviviridae'' have monopartite, linear, single ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coronaviridae
''Coronaviridae'' is a family (biology), family of Viral envelope, enveloped, positive-strand RNA viruses which infect fish, amphibians, birds, and mammals. The group includes the subfamilies ''Letovirinae,'' ''Orthocoronavirinae'', and ''Pitovirinae''. The members of the subfamily ''Orthocoronavirinae'' are known as Coronavirus, coronaviruses. The viral genome is 26–32 kilobases in length. The particles are typically decorated with large (~20 nm), club- or petal-shaped surface projections (the "peplomers" or "spikes"), which in electron micrographs of spherical particles create an image reminiscent of the solar corona. Virology The 5' and 3' ends of the genome have a Five-prime cap, cap and poly(A) tract, respectively. The viral envelope, obtained by budding through membranes of the endoplasmic reticulum (ER) or Golgi apparatus, invariably contains two virus-specified glycoprotein species, known as the spike (S) and membrane (M) proteins. The coronavirus spike protein, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Picornaviridae
Picornaviruses are a group of related nonenveloped RNA viruses which infect vertebrates including fish, mammals, and birds. They are viruses that represent a large family of small, positive-sense, single-stranded RNA viruses with a 30 nm icosahedral capsid. The viruses in this family can cause a range of diseases including the common cold, poliomyelitis, meningitis, hepatitis, and paralysis. Picornaviruses constitute the family ''Picornaviridae'', order '' Picornavirales'', and realm ''Riboviria''. There are 159 species in this family, assigned to 68 genera, most of which belong to 5 subfamilies. Notable examples are genera ''Enterovirus'' (including ''Rhinovirus'' and ''Poliovirus''), '' Aphthovirus'', '' Cardiovirus'', and '' Hepatovirus''. Etymology The name "picornavirus" has a dual etymology. Firstly, the name derives from ''picorna''- which is an acronym for "''p''oliovirus, ''i''nsensitivity to ether, ''c''oxsackievirus, ''o''rphan virus, ''r''hinovirus, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caliciviridae
The ''Caliciviridae'' are a family of "small round structured" viruses, members of Class IV of the Baltimore scheme. Caliciviridae bear resemblance to enlarged picornavirus and was formerly a separate genus within the picornaviridae. They are positive-sense, single-stranded RNA which is not segmented. Thirteen species are placed in this family, divided among eleven genera. Diseases associated with this family include feline calicivirus (respiratory disease), rabbit hemorrhagic disease virus (often fatal hepatitis), and Norwalk group of viruses (gastroenteritis). Caliciviruses naturally infect vertebrates, and have been found in a number of organisms such as humans, cattle, pigs, cats, chickens, reptiles, dolphins and amphibians. The caliciviruses have a simple construction and are not enveloped. The capsid appears hexagonal/ spherical and has icosahedral symmetry (T=1 or T=3) with a diameter of 35–39 nm. Caliciviruses are not very well studied because until 2010, they ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astroviridae
Astroviruses (''Astroviridae'') are a type of virus that was first discovered in 1975 using electron microscopes following an outbreak of diarrhea in humans. In addition to humans, astroviruses have now been isolated from numerous mammalian animal species (and are classified as genus '' Mamastrovirus'') and from avian species such as ducks, chickens, and turkey poults (classified as genus ''Avastrovirus''). Astroviruses are 28–35 nm diameter, icosahedral viruses that have a characteristic five- or six-pointed star-like surface structure when viewed by electron microscopy. Along with the Picornaviridae and the Caliciviridae, the Astroviridae comprise a third family of nonenveloped viruses whose genome is composed of plus-sense, single-stranded RNA. Astrovirus has a non-segmented, single stranded, positive sense RNA genome within a non-enveloped icosahedral capsid. Human astroviruses have been shown in numerous studies to be an important cause of gastroenteritis in young c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parvoviridae
Parvoviruses are a family of animal viruses that constitute the family ''Parvoviridae''. They have linear, single-stranded DNA (ssDNA) genomes that typically contain two genes encoding for a replication initiator protein, called NS1, and the protein the viral capsid is made of. The coding portion of the genome is flanked by telomeres at each end that form into Stem-loop, hairpin loops that are important during replication. Parvovirus virions are small compared to most viruses, at 23–28 nanometers in diameter, and contain the genome enclosed in an icosahedral capsid that has a rugged surface. Parvoviruses enter a host cell by endocytosis, travelling to the nucleus where they wait until the cell enters its replication stage. At that point, the genome is uncoated and the coding portion is replicated. Viral messenger RNA (mRNA) is then Transcription (biology), transcribed and Translation (biology), translated, resulting in NS1 initiating replication. During replication, the hairpi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
