Human-to-human flu virus transmission

How are influenza viruses transmited from human to human? Seasonal and pandemic influenza are highly contagious diseases and are spread primarily by coughing and sneezing. When they sneeze, people release tiny droplets of fluid into the air. Those tiny droplets can fly up to 1 metre and infect persons nearby by reaching susceptible cells of […]

Virus replication

In humans, the primary targets for influenza viruses are the epithelial cells in the airways and lungs. The viral HA binds to sialic acid residues on glycoproteins or glycolipids on the cell surface. The act of binding draws the virus into the cell membrane. The virus shell fuses with the cell membrane and moves through […]

Hosts of H5N1

Wild birds are the natural hosts of influenza A viruses. In principle, all subtypes of influenza A viruses can be found in them. Typically, little or no disease is caused by infection of wild birds with these avian influenza viruses, which are therefore called low pathogenic avian influenza (LPAI) viruses. However, when LPAI viruses of […]


Morphology and structure The influenza virus belongs to the RNA viruses and comes from the family of Orthomyxoviridae. It is usually spherical in shape with a diameter of 80-120 nm. There are 3 distinct types of influenza virus: A, B and C. The genome consists of 8 (type A and B viruses) or 7 (type […]