In today’s times how do we still have the flu? The flu, or influenza, is a very complex virus. We cannot just give you a shot, and you will never get the flu again. Many other diseases can be cured or prevented via vaccination, but not the flu. Why? If the flu cannot be cured then what do flu shots do?
The Flu is not one strain of a virus; instead there are many strains of the Influenza virus. These strains are broken up into categories such as Influenza A, B, C. Influenza A is carried mostly by wild aquatic birds (Influenza). Influenza B usually only infects humans, and Influenza C infects pigs, dogs, and humans (Influenza). Influenza A is the most common category that crosses over. This means it moves from one species to another species. A few people contract the virus from the source animals, and then it is spread from human to human.
If humans can contract Influenza from animals, can animals catch influenza from humans? The answer is yes. Pigs are normally the animals that can catch the human influenza, but this is where things get interesting (Diseases). If a pig is infected with Avian Influenza A and Human Influenza A at the same weird things can happen (Influenza (disease)). The viruses like to trade their genetic information, and then they create a new strain of human susceptible Avian Influenza. No human would have immunity to this because this is a new strain entirely. According to the CDC this is what caused the Bird Flu epidemic.
Influenza A is the most complex of the categories of the Influenza virus because Influenza A can be categorized into something called serotypes. These are categories based on the antibody response to the virus. The known serotypes that have infected humans are: H1N1 (Spanish and Swine Flu), H2N2 (Asian Flu), H7N3, H3N2 (Hong Kong Flu), H7N7, H1N2 (endemic in pigs, birds, and humans), H7N2, H5N1 (Bird Flu), H9N2, H10N7, and H7N9 (Influenza). The serotypes are named by H (number) and N (number); this is because the virus has two surface antigens one of the 18 types of Hemagglutinin “H” and one of the 11 types of Neuraminidase “N” (Types). There can be any combination of the two antigens, so this is why there are many pandemics associated with Influenza A. Influenza B and C are not near as complex as Influenza A; they are not subdivided, and are less common.
According to human pathology, when humans are infected with a virus they produce antibodies. These antibodies attack off the invading virus or viruses. Once your body produces antibodies for one virus you build up immunity to that virus. The Influenza virus has a very interesting approach at overcoming this obstacle. Influenza cannot replicate unless it is in a living cell; it delivers its genetic material into the nucleus so when the cell divides it will reproduce the genes of the virus. However there can be errors in the replication phase. Errors in the replication phase are called mutations. This helps the virus change and overcome the...