Patents are designed to protect creations and designs, but how long a patent lasts for is dependent on a number of factors. The length of time that a patent offers protection, depends largely on what type of patent is issued and whether required maintenance fees are paid to keep the patent active. slide 1 of 6.
A viral infection is a disease that can be caused by different kinds of viruses, of which the influenza-virus is best known.
The basic process of viral infection and virus replication occurs in 6 main steps. 1  Adsorption-virus binds to the host cell. 2  Penetration-virus injects its genome into host cell. 3  Viral Genome Replication-viral genome replicates using the host's cellular machinery.iruses may infect any type of cell including animal cells, plant cells and bacterial cells. To view an example of the process of viral infection and virus replication, see Virus Replication: Bacteriophage.