# FK's field
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> [name=Furkan Kıvanç]

> [time=Thu, May 20 2021 12:45 PM]

**Orthomyxoviruses: [Recent Advances in Animal Virology](https://www.springer.com/gp/book/9789811390722)**
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Here is some brief information about Orthomyxoviruses

{%youtube J2lIwwn1o4E%}
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- [ ] Preamble
- [ ] History
- [ ] Virus Properties
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Orthomyxoviridae is a family of RNA viruses. The family includes 7 genera, namely Influenzavirus A, Influenzavirus B, Influenzavirus C, Influenzavirus D, Isavirus, Thogotovirus, and Quaranjavirus.

Source: [Orthomyxoviridae](https://veteriankey.com/orthomyxoviridae/)
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Virions are spherical or pleomorphic with helical symmetry with a size range of 80–120 nm in diameter.
source: [Properties of Orthomyxoviruses](https://microbeonline.com/properties-orthomyxoviruses-paramyxoviruses-family/)
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Orthomyxoviruses possess 6–8 negative-sense, single-stranded RNA segments. Influenza virus types A and B and Isavirus contain eight RNA segments; influenza C and influenza D, seven RNA segments. 8 segments coding for 11 proteins.
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## Proteins ##
source: [Influenza A virus structure](https://www.mdpi.com/1999-4915/10/9/497/html)
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# Viral Replication

The viral hemagglutinin is activated in permissive tissues
by cleavage into two constituents, HA1 and HA2, linked to each other by disulfide bonds. Virions attach to cells via the binding of activated hemagglutinin to sialic acid receptors on the plasma membrane, with different orthomyxoviruses using sialic acid molecules with different carbohydrate side chains as receptors.
Entry is via receptor-mediated endocytosis; transcription complexes (nucleocapsids with associated RNA polymerase) are released into the cytoplasm after fusion between the viral envelope and the endosomal membrane. This fusion is triggered by low pH within the endosome, the result being a further conformational change in hemagglutinin structure.
Transcriptional complexes are transported into the nucleus where transcription and RNA replication take place.
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# Infection and replication of the influenza virus.

Replication cycle of influenza virus. ER, endoplasmic reticulum; M1, M2, matrix proteins; NP, nucleoprotein; NS1, NS2, non-structural proteins; Pa, PB1, PB2, proteins of the viral RNA polymerase complex; PB1-F2, non-essential strain-dependent protein linked to virulence.
source: [Fenner and White's Medical Virology](https://www.sciencedirect.com/book/9780123751560/fenner-and-whites-medical-virology)
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