What is a virus?

28 July 2004

Viruses are distinct biological entities with the following properties:

1. A virus is an infectious, obligate intracellular parasite.

2. The genetic material of a virus is either DNA or RNA.

3. The genetic material of a virus enters a host cell and directs the production of the building blocks of new virus particles (called virions).

4. New virions are made in the host cell by assembly of these building blocks.

5. The new virions produced in a host cell then transport the viral genetic material to another host cell or organism to carry out another round of infection.

Viruses are easy to understand when we reduce their properties to simple descriptions such as those listed above. The confounding issues lie in the details – and with viruses, there are many, many details.

  • Slopez

    The word virus comes from the Latin for a poisonous liquid. Virus are vesicles produced by a cell capable of carrying genetic codes and cellular material to other cells. The absorption of this material into a recipient is commonly called infection although it is not necessarily harmful. Virus produced by healthy cells are called passenger virus. Virus produced by poisonous cells are called pathogenic virus.There is strong evidence that polio was not eradicated by vaccination but by banning the use of DDT.

  • Slopez

    The word virus comes from the Latin for a poisonous liquid. Virus are vesicles produced by a cell capable of carrying genetic codes and cellular material to other cells. The absorption of this material into a recipient is commonly called infection although it is not necessarily harmful. Virus produced by healthy cells are called passenger virus. Virus produced by poisonous cells are called pathogenic virus.There is strong evidence that polio was not eradicated by vaccination but by banning the use of DDT.

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  • Mbeaving

    Baning DDT? That's completely nonsensical and does not explain historical and current instances of polio without DDT. Sound quite pseudosciency.

  • JRobertson

    I have to agree with Mbeaving. Simply imposing a ban on DDT is hardly the answer for polio eradication. Most likely it is due to the vaccines that were prescribed to children during the mid- twentieth century. If anyone is interested, I have posted some information relating to the virology of the common adenovirus infection here: http://adenovirus.com/adenovirus-virology.html

  • Roberta R

    There is nothing pseudosciency about environmental contaminants such as arsenic or DDT  turning the polio virus into a paralytic agent.  What is pseudosciency is the claim that polio spread as a consequence of increased sanitation,  a claim still made by  some in the medical establishment.