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

For the longest time, virologists were fairly certain that there was nothing on Earth comparable to viruses. Then, in 1964, Dr. Theodore Diener made an amazing discovery, which questioned these old theories. Diener had accidentally stumbled upon a new and exotic infecting agent. This new microorganism had the same devastating effects as viruses, but lacked many of the properties that define viruses. Viroids are found only in plants and are believed to be a more primitive version of the ordinary virus. In fact, viroids may be living fossils of the genetic messengers (see The Evolutionary History of Viruses) which existed before animal cells were created. Viroids are naked strings of amino acids with absolutely no covering of their genetic material. They are free-floating, single stranded RNA. Viroids are known for their simplicity. Once thought to be the smallest infectious agents, Viruses are now considered larger and more complex than viroids. There was great skepticism concerning his discovery, but Diener was eventually able to prove the existence of the viroid, the lethal younger brother of the virus.


Everyday, virologists study harmful viruses trying to understand exactly what these mysterious beings are, and how they behave. The goal of their research is simple. They want to find ways to prevent control and ultimately cure many of the deadly viruses that plague life on Earth. Already their work has been able to prevent several epidemics and wipe out the threats of many viruses. In fact, many vaccines can already control viruses such as smallpox, yellow fever, polio and influenza. The most dangerous viruses, including AIDS and certain brain-destroying viruses are of the highest priority right now. An incredible amount of time and money is being poured into the search for medications and vaccines to help solve their devastating effects. A drug called AZT is one important result of these studies. AZT blocks virus replication in cells and has helped many AIDS patients to resist infections. Further studies are also being done to try and connect viruses with cancer.

By studying viruses directly, scientists have been able to learn a lot about ourselves in the process. We have discovered an incredible amount of information about the actual DNA, RNA and genes of living beings. Once they are able to identify the life controlling functions of specific genes, they may be able to design special drugs to target virus vulnerabilities.

Unfortunately, development of drugs cost biotech companies millions of dollars of research and testing. This limits the types of disease that are being studied. Diseases that predominately affect the poor are often ignored because they are not "profitable" to look at. However, diseases that affect the poor are the ones that are of the greatest concern. These are the diseases that affect the majority of the human population. Thus, the irony of the whole situation.

We've come a long way since Jenner and Pasteur. With our new technology and methods of experimentation, scientists aim to ultimately strip viruses of their mystery, and learn how to prevent the disaster they cause.

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