What do the H and N mean in flu?
Influenza A viruses are classified by subtypes based on the properties of their hemagglutinin (H) and neuraminidase (N) surface proteins.
There are 18 different HA subtypes and 11 different NA subtypes.
Subtypes are named by combining the H and N numbers – e.g., A(H1N1), A(H3N2)..
How does influenza infect a host?
The influenza virus enters the host cell by having its hemagglutinin bind to the sialic acid found on glycoproteins or glycolipid receptors of the host. The cell then endocytoses the virus. In the acidic environment of the endosomes, the virus changes shape and fuses its envelope with the endosomal membrane.
Can you infect someone with the flu?
Person to Person People with flu can spread it to others up to about 6 feet away. Most experts think that flu viruses spread mainly by droplets made when people with flu cough, sneeze or talk. These droplets can land in the mouths or noses of people who are nearby or possibly be inhaled into the lungs.
Is it safe to be around someone with the flu?
Be especially cautious for the first two to three days, and stay six feet away from the germy person during that time. People are much more likely to get infected with the flu from being around other sick people than they are from touching virus-laden surfaces.
Is Flu A or B worse?
Frequently asked questions about Influenza A and B Influenza type A and type B are similar, but type A is overall more prevalent, sometimes more severe, and can cause flu epidemics and pandemics.
Whats the difference between Flu A and Flu B?
Unlike type A flu viruses, type B flu is found only in humans. Type B flu may cause a less severe reaction than type A flu virus, but occasionally, type B flu can still be extremely harmful. Influenza type B viruses are not classified by subtype and do not cause pandemics.
What is the host for the flu?
Influenza A viruses infect a wide range of host species, whereas the main hosts for influenza B and C are humans, and influenza D virus has thus far been found to infect cattle, goats and pigs1 (Fig. 1). Influenza A virus is a paradigm for an emerging virus.
Does influenza kill cells?
However, in the case of severe influenza virus infection, dead cells can be observed on the airways and alveoli of the lungs of infected donors. Influenza virus targets mainly airway and alveolar epithelial cells in vivo [4,5].
What cells does the flu infect?
The main targets of the influenza virus are the columnar epithelial cells of the respiratory tract. These cells may be susceptible to infection if the viral receptor is present and functional.