Table Of Contents

  Characteristics of a Virus
    - Evolutionary History
    - Vaccines
    - Discovery of the Virus
Viral Infections
    - The Host
    - How Viruses Infect
    - Types of Infections
    - What's an Infection?
  Beyond Viruses: Viriods
  Virus Research
  Infection Prevention

Most people relate viruses with 'the cold' and 'the flu,' viral infections that bring out a familiar set of symptoms, and then leave as quickly as they show up. These are examples of acute infections. Acute infections cause many of the minor illnesses that humans have experience with. This type of viral infection is, on the most part, rather harmless causing discomfort and minor indications of cell damage. Acute infections, however, can become much worse if they are recurring and do less damage to host cells. In this case acute infections become chronic infections. Chronic infections can be dangerous and sometimes deadly. In cases of chronic infection host cells may not be damaged at all, but their functions may be disturbed. This can cause serious recurring illness and disease. In many cases, chronic infections can be monitored and the viruses that cause them can be cultured in labs. However, scientists can not culture the types of viruses that cause latent infections. Latent infections come from viruses that can manage to evade attacks of the host's immune system. Latent viruses are persistent and frequently cause deadly diseases.


In normal cells, nucleic acids make up the all the genetic material found in the nuclei. Bundles of nucleic acids are collectively called genes, and they sting together to for chromosomes. There are a total of 46 chromosomes in every normal human cell nucleus. The smaller packets of nucleic acids make it possible for normal cells to manufacture proteins, enzymes, energy and heat. They also allow cells to carry out the everyday functions of life and pass on their characteristic to their offspring. If we take the time to inspect these nucleic acids more closely, we would see that they are specialized molecules known as DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). These molecules are the basic building blocks of all life and act as the master plans for all the cells in a body.

While DNA can be considered the director of operations, RNA specializes in carrying 'messages' from the nucleus to different parts of the cell. DNA is made up of many separate fragments that each contains different coded messages. In a process called transcription, a rough copy of the DNA's gene is decoded and written onto a strand of RNA. The result is a form of messenger RNA, which travels to each part of the cell carrying specific instructions and commands. This process is vital for the survival of cells in a body, and if something hampers its completion or alters the instructions, the results can be deadly.

Viruses are tiny packages of genetic material without a living cell enveloping them. The key to their power is the nucleic acid they possess. When a virus attacks and infects a vulnerable living cell, it pours its own DNA and/or RNA inside. Once inside, the hereditary material begins a virtual Coup d'état. It attaches itself to the cell's existing DNA and sets up a new command system. Now, instead of producing substances the cell needs to survive, it is forced to produce viral nucleic acid. One cell can be used to create thousands of new, mature viruses. The fastest virus only needs 24 minutes to explode a cell and release new virus particles. Cells are damaged and destroyed with each new birth, and chaos is all that is left in the wake.

.. Next Page