Search results
Results from the WOW.Com Content Network
It is now known that this was caused by an immunologically novel H1N1 subtype of influenza A. [43] The next pandemic took place in 1957, the "Asian flu", which was caused by a H2N2 subtype of the virus in which the genome segments coding for HA and NA appeared to have derived from avian influenza strains by reassortment, while the remainder of ...
Influenza A viruses are further classified, based on the viral surface proteins hemagglutinin (HA or H) and neuraminidase (NA or N). 18 HA subtypes (or serotypes) and 11 NA subtypes of influenza A virus have been isolated in nature. Among these, the HA subtype 1-16 and NA subtype 1-9 are found in wild waterfowl and shorebirds and the HA ...
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.
Influenza viruses have a negative-sense, single-stranded RNA genome that is segmented. The negative sense of the genome means it can be used as a template to synthesize messenger RNA (mRNA). [10] Influenza A virus and influenza B virus have eight genome segments that encode 10 major proteins.
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 ]
Further analysis of HA has shown it to have a very small effective population size relative to the census size of the virus population, as expected for a gene undergoing strong positive selection. [44] However, across the influenza genome, there is surprisingly little variation in effective population size; all genes are nearly equally low. [45]
Influenza A virus subtype H5N1 (A/H5N1) is a subtype of the influenza A virus, which causes the disease avian influenza (often referred to as "bird flu"). It is enzootic (maintained in the population) in many bird populations, and also panzootic (affecting animals of many species over a wide area). [ 1 ]
Influenza A viruses differ by comprising multiple ribonucleoproteins, the viral NP protein organizes the RNA into a helical structure. The size is also different; the tobacco mosaic virus has a 16.33 protein subunits per helical turn, [22] while the influenza A virus has a 28 amino acid tail loop. [25]