How Do Type A Viruses Cause A Pandemic?
Type A viruses are further classified into strains. These strains can continuously evolve into different strains. Their ability to exchange genetic material with other viruses and create new influenza viruses makes them unpredictable and difficult to fight with. Humans have to develop new immunity (antibodies) every time new strains are created. Viruses cannot repair genetic damage, small changes known as “Antigen Drift”, are continuously creating new strains of viruses. However when genetic material from Type A viruses from different species – say a bird and a human, comes together and merges, an entirely new strain is created. This is known as “Antigen Shift” Humans have no immunity to such a strain and the strain can spread rapidly causing a Pandemic.
