Influenza is a viral infection that include 4 categories of illnesses there is Influenza A, B, C, and D. Influenza A and B are the types that typically pose a threat, while C is a less threatening type and D primarily affects cattle and isn't known to inflict sickness upon humans. Influenza A viruses are classified depending upon the proteins they have on the surface of the virus. The proteins are hemagglutinin and neuraminidase.
Influenza typically attacks the elderly that have weak immune systems newborns from 6-59 months of age, pregnant women, and health care workers.
The goal of Influenza is to spread itself and pass on its genes to survive. The influenza virus attaches to the host cell and inserts the DNA from the virus to the cell so when the cell reproduces the infected DNA spreads with it.
Credits:
Created with images by Sellers Patton - "Sneezy" • PhotoLizM - "injection medical shot" • Rusty Clark ~ 100K Photos - "FLU" • JeepersMedia - "Flu Shots"