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Information about Paramyxovirus

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Paramyxoviruses
Virus classification
Group:Group V ((-)ssRNA)
Order:Mononegavirales
Family:Paramyxoviridae
Genera
Subfamily Paramyxovirinae
   Avulavirus
   Henipavirus
   Morbillivirus
   Respirovirus
   Rubulavirus
Subfamily Pneumovirinae
   Pneumovirus
   Metapneumovirus
Paramyxoviruses are viruses of the Paramyxoviridae family of the Mononegavirales order; they are negative-sense single-stranded RNA viruses responsible for a number of human and animal diseases.

Genera

Physical structure

Virions are enveloped and can be spherical, filamentous or pleomorphic. Fusion proteins and attachment proteins appear as spikes on the virion surface. Matrix proteins inside the envelope stabilise virus structure. The nucleocapsid core is composed of the genomic RNA, nucleocapsid proteins, phosphoproteins and polymerase proteins.

Genome structure

The genome consists of a single segment of negative-sense RNA, 15-19 kilobases in length and containing 6-10 genes. Extracistronic (non-coding) regions include:
  • A 3’ leader sequence, 50 nucleotides in length which acts as a transcriptional promoter.
  • A 5’ trailer sequence, 50-161 nucleotides long
  • Intergenomic regions between each gene which are three nucleotides long for morbillivirus, respirovirus and henipavirus, variable length (1-56 nucleotides) for rubulavirus and pneumovirinae.
Each gene contains transcription start/stop signals at the beginning and end which are transcribed as part of the gene.

Gene sequence within the genome is conserved across the family due to a phenomenon known as transcriptional polarity (see Mononegavirales) in which genes closest to the 3’ end of the genome are transcribed in greater abundance than those towards the 5’ end. This mechanism acts as a form of transcriptional regulation.

The gene sequence is:
  • Nucleocapsid – Phosphoprotein – Matrix – Fusion – Attachment – Large (polymerase)

Proteins

  • N – the nucleocapsid protein associates with genomic RNA (one molecule per hexamer) and protects the RNA from nuclease digestion
  • P – the phosphoprotein binds to the N and L proteins and forms part of the RNA polymerase complex
  • M – the matrix protein assembles between the envelope and the nucleocapsid core, it organises and maintains virion structure
  • F – the fusion protein projects from the envelope surface as a trimer, and mediates cell entry by inducing fusion between the viral envelope and the cell membrane by class I fusion. One of the defining characteristics of members of the paramyxoviridae family is the requirement for a neutral pH for fusogenic activity.
  • H/HN/G – the cell attachment proteins span the viral envelope and project from the surface as spikes. They bind to sialic acid on the cell surface and facilitate cell entry. Note that the receptor for measles virus is unknown. Proteins are designated H for morbilliviruses and henipaviruses as they possess haemagglutination activity, observed as an ability to cause red blood cells to clump. HN attachment proteins occur in respiroviruses and rubulaviruses. These possess both haemagglutination and neuraminidase activity which cleaves sialic acid on the cell surface, preventing viral particles from reattaching to previously infected cells. Attachment proteins with neither haemagglutination nor neuraminidase activity are designated G (glycoprotein). These occur in members of pneumovirinae.
  • L – the large protein is the catalytic subunit of RNA dependent RNA polymerase (RDRP)
  • Accessory proteins – a mechanism known as RNA editing (see Mononegavirales) allows multiple proteins to be produced from the P gene. These are not essential for replication but may aid in survival in vitro or may be involved in regulating the switch from mRNA synthesis to antigenome synthesis.

Pathogenic paramyxoviruses

A number of important human diseases are caused by paramyxoviruses. These include mumps, measles, which caused 745,000 deaths in 2001 and respiratory syncytial virus (RSV) which is the major cause of bronchiolitis and pneumonia in infants and children.

The parainfluenza viruses are the second most common causes of respiratory tract disease in infants and children. They can cause pneumonia, bronchitis and croup in children and the elderly.

Human metapneumovirus, initially described in about 2001, is also implicated in bronchitis, especially in children.

Paramyxoviruses are also responsible for a range of diseases in other animal species, for example canine distemper virus (dogs), phocine distemper virus (seals), cetacean morbillivirus (dolphins and porpoises) Newcastle disease virus (birds) and rinderpest virus (cattle). Some paramyxoviruses such as the henipaviruses are zoonotic pathogens, occurring naturally in an animal host, but also able to infect humans.

Hendra virus (HeV) and Nipah virus (NiV) in the genus Henipavirus have emerged in humans and livestock in Australia and Southeast Asia. Both viruses are contagious, highly virulent, and capable of infecting a number of mammalian species and causing potentially fatal disease. Due to the lack of a licensed vaccine or antiviral therapies, HeV and NiV are designated as biosafety level (BSL) 4 agents. The genomic structure of both viruses is that of a typical paramyxovirus.[1]

See also

External links

References

1. ^ Sawatsky et al (2008). "Hendra and Nipah Virus", Animal Viruses: Molecular Biology. Caister Academic Press. ISBN 978-1-904455-22-6. 
Virus classification involves naming and placing viruses into a taxonomic system. Like the relatively consistent classification systems seen for cellular organisms, virus classification is the subject of ongoing debate and proposals.
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Mononegavirales

Families
Paramyxoviridae
Rhabdoviridae
Filoviridae
Bornaviridae
The Mononegavirales are an order of viruses comprising species that have a non-segmented, negative sense RNA genome.
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The genus Avulavirus is one of eight genera in the family Paramyxoviridae and contains viruses that used to be classified in the genus Rubulavirus, but which infect birds (hence the name avian rubulavirus) and translate protein V from an edited RNA transcript.
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Henipavirus is a genus of the family Paramyxoviridae, order Mononegavirales containing two members, Hendravirus and Nipahvirus. The henipaviruses are naturally harboured by Pteropid fruit bats (flying foxes) and are characterised by a large genome,
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Morbillivirus is a genus belonging to the Paramyxoviridae family of viruses in the order Mononegavirales. Many members of the genus cause diseases, such as rinderpest and measles, and are highly infectious.
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Human metapneumovirus (hMPV) was isolated for the first time in 2001 in the Netherlands by using the RAP-PCR technique for identification of unknown viruses growing in cultured cells.
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Mononegavirales

Families
Paramyxoviridae
Rhabdoviridae
Filoviridae
Bornaviridae
The Mononegavirales are an order of viruses comprising species that have a non-segmented, negative sense RNA genome.
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An RNA virus is a virus which belongs to either Group III, Group IV or Group V of the Baltimore classification system of classifying viruses. As such, they possess ribonucleic acid (RNA) as their genetic material and do not replicate using a DNA
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Left: An RNA strand, with its nitrogenous bases. Right: Double-stranded DNA.]] Ribonucleic acid or RNA is a nucleic acid polymer consisting of nucleotide monomers, which plays several important roles in the processes of translating genetic information from
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disease is an abnormal condition of an organism that impairs bodily functions. In human beings, "disease" is often used more broadly to refer to any condition that causes discomfort, dysfunction, distress, social problems, and/or death to the person afflicted, or similar problems
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The genus Avulavirus is one of eight genera in the family Paramyxoviridae and contains viruses that used to be classified in the genus Rubulavirus, but which infect birds (hence the name avian rubulavirus) and translate protein V from an edited RNA transcript.
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Newcastle disease is a highly contagious zoonotic bird disease affecting many domestic and wild avian species. Its effects are most notable in domestic poultry due to their high susceptibility and the potential for severe impacts of an epidemic on the poultry industries.
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Henipavirus is a genus of the family Paramyxoviridae, order Mononegavirales containing two members, Hendravirus and Nipahvirus. The henipaviruses are naturally harboured by Pteropid fruit bats (flying foxes) and are characterised by a large genome,
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Henipavirus is a genus of the family Paramyxoviridae, order Mononegavirales containing two members, Hendravirus and Nipahvirus. The henipaviruses are naturally harboured by Pteropid fruit bats (flying foxes) and are characterised by a large genome,
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Henipavirus is a genus of the family Paramyxoviridae, order Mononegavirales containing two members, Hendravirus and Nipahvirus. The henipaviruses are naturally harboured by Pteropid fruit bats (flying foxes) and are characterised by a large genome,
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Morbillivirus is a genus belonging to the Paramyxoviridae family of viruses in the order Mononegavirales. Many members of the genus cause diseases, such as rinderpest and measles, and are highly infectious.
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Measles
Classification & external resources

How Measles affects the skin.
ICD-10 B 05. .-
ICD-9 055

DiseasesDB 7890
MedlinePlus 001569
eMedicine derm/259   emerg/389
Measles virus


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Rinderpest virus

Rinderpest is an infectious viral disease of cattle, domestic buffalo, and some species of wildlife. It is commonly referred to as cattle plague or steppe murrain.
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Canine distemper is a viral disease affecting animals in the families Canidae, Mustelidae, Mephitidae, Procyonidae, Pinnipedia and possibly Felidae (though not domestic cats; feline distemper or panleukopenia is a virus exclusive to cats).
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'Phocine distemper virus

Phocine distemper virus (PDV) is a paramyxovirus of the genus morbillivirus that is pathogenic for pinniped species, particularly seals.[1] Clinical signs include laboured breathing, fever and nervous symptoms.
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Sendai virus

Sendai virus (SeV), also known as murine parainfluenza virus type 1, is a negative sense, single-stranded RNA virus of the Paramyxoviridae family[1], a group of viruses featuring, notably, the Morbillivirus
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Human parainfluenza viruses (HPIVs) are a group of four distinct serotypes of single-stranded RNA viruses belonging to the paramyxovirus family. They are the second most common cause of lower respiratory tract infection in younger children.
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Acute nasopharyngitis
Classification & external resources

ICD-10 J 00.0
ICD-9 460

DiseasesDB 31088
MedlinePlus 000678
eMedicine med/2339  
MeSH D003139 Acute viral nasopharyngitis, or acute coryza
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Mumps virus

For other uses of the word MUMPS, see .


Mumps or epidemic parotitis is a viral disease of humans.
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Menangle virus is a virus that infects pigs, humans and bats. It was first identified in 1997 after a piggery in Menangle near Sydney, NSW, Australia was struck with a high number of still born births and deformities during farrowing.
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Tioman virus is a paramyxovirus first isolated from the urine of island fruit bats (Pteropus hypomelanus) on Tioman Island, Malaysia in 2000. The virus was discovered during efforts to identify the natural host of Nipah virus which was responsible for a large outbreak of
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Human respiratory syncytial virus
Classification & external resources

ICD-10 B 97.4
ICD-9 079.6

DiseasesDB 11387
MedlinePlus 001564
eMedicine ped/2706  
MeSH D018357

Human respiratory syncytial virus
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Human metapneumovirus (hMPV) was isolated for the first time in 2001 in the Netherlands by using the RAP-PCR technique for identification of unknown viruses growing in cultured cells.
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In biology the genome of an organism is its whole hereditary information and is encoded in the DNA (or, for some viruses, RNA). This includes both the genes and the non-coding sequences of the DNA.
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