Viruses gain entry into host cells via several sites such as the skin, gastrointestinal tract, and respiratory tract. Once an infection has occurred, the virus may replicate in host cells at the site of infection or they may also spread to other locations. Animal viruses typically spread throughout the body mainly by way of the bloodstream, but can also be spread via the nervous system. Viruses have several methods to counter host immune system responses. Some viruses, like HIV, destroy immune system cells. Other viruses, such as influenza viruses, experience changes in their genes leading to antigenic drift or antigenic shift. In antigenic drift, viral genes mutate altering virus surface proteins. This results in the development of a new virus strain that may not be recognized by host antibodies. Antibodies connect to specific virus antigens to identify them as 'invaders' that must be destroyed. While antigenic drift happens gradually over time, antigenetic shift occurs rapidly. In antigenetic shift, a new virus subtype is produced through the combination of genes from different viral strains. Antigenetic shifts are associated with pandemics as host populations have no immunity to the new viral strain. Journals are the major source of knowledge for young and aspiring generations who are keen in pursuing their careers in science. This system provides easy access to networks of scientific journals. Authors who contribute their scholarly works to Open Access journals gain remarkable reputation as the research scholars explore these works extensively. This process assures considerable impact factor for the journal and good reputation to the authors that add value to their Academic Performance Index (API) Score. Because of the free access open access journals impact factors are improving.
Last date updated on July, 2014