Coronavirus pathophysiology: Difference between revisions
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===Pathogenicity=== | |||
oronaviruses primarily infect the upper respiratory and [[gastrointestinal tract]] of mammals and birds. Four to five different currently known strains of coronaviruses infect humans. The most publicized human coronavirus, [[SARS coronavirus|SARS-CoV]] which causes [[Severe acute respiratory syndrome|SARS]], has a unique pathogenesis because it causes both upper and lower respiratory tract infections and can also cause [[gastroenteritis]]. Coronaviruses are believed to cause a significant percentage of all [[common cold]]s in human adults. Coronaviruses cause colds in humans primarily in the winter and early spring seasons. The significance and economic impact of coronaviruses as causative agents of the common cold are hard to assess because, unlike [[rhinovirus]]es (another common cold virus), human coronaviruses are difficult to grow in the laboratory. | |||
These viruses infect a variety of mammals and birds. The exact number of human isolates are not known as many cannot be grown in culture. In humans, they cause: | |||
* Respiratory infections (common), including Severe Acute Respiratory Syndrome (SARS) | |||
* Enteric infections (occasional - mostly in infants <12 months) | |||
* Neurological syndromes (rare) | |||
Coronaviruses also cause a range of diseases in farm animals and domesticated pets, some of which can be serious and are a threat to the farming industry. Economically significant coronaviruses of farm animals include [[porcine]] coronavirus (transmissible gastroenteritis, TGE) and [[bovine]] coronavirus, which both result in [[diarrhea]] in young animals. Feline enteric coronavirus is a pathogen of minor clinical significance, but spontaneous mutation of this virus can result in feline infectious [[peritonitis]] (FIP), a disease associated with high mortality. There are two types of [[canine coronavirus]] (CCoV), one that causes mild gastrointestinal disease and one that has been found to cause respiratory disease. [[Mouse hepatitis virus]] (MHV) is a coronavirus that causes an epidemic [[murine]] illness with high mortality, especially among colonies of laboratory mice. Prior to the discovery of SARS-CoV, MHV had been the best-studied coronavirus both ''in vivo'' and ''in vitro'' as well as at the molecular level. Some strains of MHV cause a progressive demyelinating encephalitis in mice which has been used as a murine model for [[multiple sclerosis]]. Significant research efforts have been focused on elucidating the [[viral pathogenesis]] of these animal coronaviruses, especially by virologists interested in veterinary and [[zoonotic]] diseases. | |||
HCoV-229E and HCoV-OC43 cause the common cold, a self-limiting upper respiratory tract infection. Infection can lead to a number of illnesses such as bronchitis, gastroenteritis, progressive demyelinating encephalitis, diarrhea, peritonitis, nasal obstruction, [[rhinorrhea]], sneezing, sore throat and cough. They can cause more severe lower respiratory tract infection, including pneumonia in infants, elderly and immunocompromised individuals. | |||
HCoV-229E is a common agent if coryza, whereas HCoV-OC43 is generally characterized by sore throats. | |||
HCoV-NL63 causes [[laryngotracheitis]] ([[croup]]) and nonfatal upper and [[lower respiratory tract infection]]s in children, elderly, and immunocompromised individuals. HCoV-HKU1 causes mild upper respiratory diseases, the [[common cold]], [[bronchiolitis]], and [[pneumonia]], with symptoms such as [[rhinorrhea]], [[fever]], [[cough]], [[febrile seizure]], and [[wheezing]]. More severe illness may occur in children, adults with underlying disease, the elderly, and may be associated with gastrointestinal illness | |||
==References== | ==References== | ||
Revision as of 03:39, 3 January 2013
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Aditya Govindavarjhulla, M.B.B.S. [2]
Pathophysiology
Structure
Coronaviruses are enveloped viruses with a positive-sense single-stranded RNA genome and a helical symmetry. The genomic size of coronaviruses ranges from approximately 16 to 31 kilobases, extraordinarily large for an RNA virus. The name coronavirus is derived from the greek (κορώνα, meaning crown) as the virus envelope appears under electron microscopy (E.M.) to be crowned by a characteristic ring of small bulbous structures. This morphology is actually formed by the viral spike (S) peplomers, which are proteins that populate the surface of the virus and determine host tropism. Coronaviruses are grouped in the order Nidovirales, named for the Latin (nidus, meaning nest) as all viruses in this order produce a 3' co-terminal nested set of subgenomic mRNA's during infection.
Proteins that contribute to the overall structure of all coronaviruses are the spike (S), envelope (E), membrane (M) and nucleocapsid (N). In the specific case of SARS, a defined receptor-binding domain on S mediates the attachment of the virus to its cellular receptor, angiotensin-converting enzyme 2 (ACE2).[1] Members of the group 2 coronaviruses also have a shorter spike-like protein called hemagglutinin esterase (HE) encoded in their genome, but for some reason this protein is not always brought to expression (produced) in the cell.[2]
Pathogenicity
oronaviruses primarily infect the upper respiratory and gastrointestinal tract of mammals and birds. Four to five different currently known strains of coronaviruses infect humans. The most publicized human coronavirus, SARS-CoV which causes SARS, has a unique pathogenesis because it causes both upper and lower respiratory tract infections and can also cause gastroenteritis. Coronaviruses are believed to cause a significant percentage of all common colds in human adults. Coronaviruses cause colds in humans primarily in the winter and early spring seasons. The significance and economic impact of coronaviruses as causative agents of the common cold are hard to assess because, unlike rhinoviruses (another common cold virus), human coronaviruses are difficult to grow in the laboratory.
These viruses infect a variety of mammals and birds. The exact number of human isolates are not known as many cannot be grown in culture. In humans, they cause:
- Respiratory infections (common), including Severe Acute Respiratory Syndrome (SARS)
- Enteric infections (occasional - mostly in infants <12 months)
- Neurological syndromes (rare)
Coronaviruses also cause a range of diseases in farm animals and domesticated pets, some of which can be serious and are a threat to the farming industry. Economically significant coronaviruses of farm animals include porcine coronavirus (transmissible gastroenteritis, TGE) and bovine coronavirus, which both result in diarrhea in young animals. Feline enteric coronavirus is a pathogen of minor clinical significance, but spontaneous mutation of this virus can result in feline infectious peritonitis (FIP), a disease associated with high mortality. There are two types of canine coronavirus (CCoV), one that causes mild gastrointestinal disease and one that has been found to cause respiratory disease. Mouse hepatitis virus (MHV) is a coronavirus that causes an epidemic murine illness with high mortality, especially among colonies of laboratory mice. Prior to the discovery of SARS-CoV, MHV had been the best-studied coronavirus both in vivo and in vitro as well as at the molecular level. Some strains of MHV cause a progressive demyelinating encephalitis in mice which has been used as a murine model for multiple sclerosis. Significant research efforts have been focused on elucidating the viral pathogenesis of these animal coronaviruses, especially by virologists interested in veterinary and zoonotic diseases.
HCoV-229E and HCoV-OC43 cause the common cold, a self-limiting upper respiratory tract infection. Infection can lead to a number of illnesses such as bronchitis, gastroenteritis, progressive demyelinating encephalitis, diarrhea, peritonitis, nasal obstruction, rhinorrhea, sneezing, sore throat and cough. They can cause more severe lower respiratory tract infection, including pneumonia in infants, elderly and immunocompromised individuals.
HCoV-229E is a common agent if coryza, whereas HCoV-OC43 is generally characterized by sore throats.
HCoV-NL63 causes laryngotracheitis (croup) and nonfatal upper and lower respiratory tract infections in children, elderly, and immunocompromised individuals. HCoV-HKU1 causes mild upper respiratory diseases, the common cold, bronchiolitis, and pneumonia, with symptoms such as rhinorrhea, fever, cough, febrile seizure, and wheezing. More severe illness may occur in children, adults with underlying disease, the elderly, and may be associated with gastrointestinal illness
References
- ↑ Li, Fang, et. al. (2005). "Structure of SARS Coronavirus Spike Receptor-Binding Domain Complexed with Receptor". Science. 309: 1864&ndash, 1868. doi:10.1126/science.1116480.
- ↑ de Haan CAM, Rottier PJM (2005). "Molecular Interactions in the Assembly of Coronaviruses". Advances in Virus Research. 64: 185&ndash, 186.