Search results
Results From The WOW.Com Content Network
Influenza A virus structure. The influenzavirus virion is pleomorphic; the viral envelope can occur in spherical and filamentous forms. In general, the virus's morphology is ellipsoidal with particles 100–120 nm in diameter, or filamentous with particles 80–100 nm in diameter and up to 20 μm long. [5]
The subtypes of influenza A virus are estimated to have diverged 2,000 years ago. Influenza viruses A and B are estimated to have diverged from a single ancestor around 4,000 years ago, while the ancestor of influenza viruses A and B and the ancestor of influenza virus C are estimated to have diverged from a common ancestor around 8,000 years ago.
Two key processes that influenza viruses evolve through are antigenic drift and antigenic shift. Antigenic drift is when an influenza virus' antigens change due to the gradual accumulation of mutations in the antigen's (HA or NA) gene. [19] This can occur in response to evolutionary pressure exerted by the host immune response. Antigenic drift ...
To unambiguously describe a specific isolate of virus, researchers use the Influenza virus nomenclature, [21] which describes, among other things, the subtype, year, and place of collection. Some examples include: [22] A/Rio de Janeiro/62434/2021 (H3N2). [22] The starting A indicates that the virus is an influenza A virus.
The G4 virus, also known as the "G4 swine flu virus" (G4) and "G4 EA H1N1", is a swine influenza virus strain discovered in China. [68] The virus is a variant genotype 4 (G4) Eurasian avian-like (EA) H1N1 virus that mainly affects pigs, but there is some evidence of it infecting people. [ 68 ]
Influenza viruses are members of the family Orthomyxoviridae. [2] Influenza viruses A, B, C, and D represent the four antigenic types of influenza viruses. [3] Of the four antigenic types, influenza A virus is the most severe, influenza B virus is less severe but can still cause outbreaks, and influenza C virus is usually only associated with minor symptoms.
Influenza viruses: You’re likely familiar with the seasonal flu, but in the last century there have also been four influenza pandemics: the infamous Spanish Flu pandemic in 1918, the H2N2 flu ...
The ancestor of influenza viruses A and B and the ancestor of influenza virus C are estimated to have diverged from a common ancestor around 8,000 years ago. Influenza viruses A and B are estimated to have diverged from a single ancestor around 4,000 years ago, while the subtypes of influenza A virus are estimated to have diverged 2,000 years ...