The Immortal Virus: Influenza a H1N1

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  • Topic: Influenza, Influenza A virus subtype H1N1, Pandemic
  • Pages : 5 (1779 words )
  • Download(s) : 123
  • Published : June 29, 2011
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Viruses cause most of the disease that still plague the industrialized world. It ranges from the common cold, influenza, herpes, SARS, and AIDS. Although we have immunizations against many viral diseases and are adept at treating the symptoms of others, the ability of virus to replicate and mutate allow them almost impossible to stop an ongoing war for centuries. A virus is “a miniscule, acellular, infectious agent having one or several pieces of nucleic acid; either DNA or RNA, but never both” (Bauman 378). Influenza A H1N1 virus is a subtype of influenza virus A and the most cause of influenza/flu in humans.

Viruses are considered non-living because of their prodigious reproductive abilities. They cannot live on their own and must have a host cell to carry out their life-staining functions or reproduce. Since viruses lack ribosomes, they cannot synthesis proteins. Instead, they must use the ribosomes of their host cells to translate viral messenger RNA into viral proteins. Virus cannot generate or store energy in the form of adenosine triphosphate (ATP), but have to derive their energy, and all other metabolic functions, from the host cell (Virus Structure). All viruses contain nucleic acid. Somes viruses can be enclosed by an envelope of fat and proteins molecules. In its infective form, outside the cell, a virus particle is called a virion. Each virion contains at least one unique protein synthesized by specific genes in its nucleic acid. Viroids are disease-causing organism that contain only nucleic acid and have no structural proteins (Structure of Cells and Viruses). The classification of viruses is sorted by the organism they infect, animals, plants or bacteria. Viruses have tail fibers to attach their host by proteinaceous pin and it contracts to penetrate the cell wall and underlying membrane in order to inject viral nucleic acids in the cell (Virus Structure). Influenza A H1N1, also called swine flu, is any strain of the influenza family of viruses that is endemic in pigs. Influenza A causes the most serious and widespread human epidemics and pandemics. Influenza A infects approximately 10% of the population in the US each year and causes approximately 35,000 deaths annually (H1N1 (Swine Flu)). That's considered to be a good year considering Influenza A also makes a recurring appearance every 10 to 15 years as a highly virulent form that is responsible for epidemics. The reason Influenza A makes a top candidate for pandemics in its genomic layout. Two proteins , hemagglutinin and neuraminidase, in the coat of the influenza A virus allow it to infect cells and, once the virus has replicated, to break out and spread to other cells (How H1N1 Infects Human Cells). Hemagglutinin (H or HA) is a glycoprotein on the viral coat that binds to sialic acid receptors in the membranes of cells that line the host’s respiratory tract. After H binds to these receptors, the viral and cellular membranes fuse, and the virus is taken into the cell along with a small envelope of cellular membrane. Once inside the cell, the viral genome escapes from its covering, migrates to the cell’s nucleus, crosses the nuclear membrane, and disrupt the host cell’s machinery to make copies of itself (How H1N1 Infects Human Cells). Additional copies of H, N, and viral matrix proteins are made as well. These manufactured viral components migrate back to the cell membrane where they bud out from the cell, taking a wrapping of cellular membrane for their new coats. However, the new viral coats still contain sialic acid receptors from the host cell. These cellular receptors will bind with viral H proteins and prevent the viruses from exiting. It is the task of neuraminidase (N or NA) to enzymatically cleave the sialic acid receptors, thus allowing the virus to break free from the host cell. The virus is now able to bind to another respiratory cell and begin the process anew (How H1N1 Infects Human...
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