(The Biochemical Kind)
What is a Virus?
A virus is basically DNA or RNA, either single or double-stranded,
enclosed in a protein capsule (capsid). Viruses are not technically alive
because scientists define the basic unit of life as the cell, and viruses
are not cellular. Viruses vary widely in structure and function, and some
may even have a lipid envelope (like a cell membrane) around their protein
capsid, but viruses lack cellular organelles ("mini-organs") and viruses
cannot reproduce on their own. Viruses reproduce by entering the host cell
(like one of your cells) and hijacking the cell's reproductive machinery
so that the cell starts replicating the virus' DNA or RNA and making virus
sub-components (like an assembly line) that get put together to make more
viruses. Often, the viruses become so numerous that eventually they lyse
the cell (make the cell explode) and are released into the host's system
where they travel to other cells and repeat the process. Sometimes newly-made
viruses can escape the cell by just "budding" out of the cell, and the
host cell may survive.
||This Digitized Electron Micrograph
shows AIDS daughter virus particles leaving a cell.
The actual virus is HIV (The Human
Immunodeficiency Virus). AIDS is Acquired Immune Deficiency Syndrome, the
disease caused by HIV.
What is a Bacteriophage?
A bacteriophage is a virus that infects a bacteria. The term "phage"
refers to a virus.
Do Antibiotics Work on Viruses?
No! Antibiotics only work on bacteria. Doctors will sometimes prescribe
antiobiotics when you have a virus to combat secondary bacterial infection,
but the antibiotics will have no direct effect on the virus itself.
How Are Viruses Treated? Can We Cure Viruses? What are
Viruses are generally not curable. They replicate fast and often have
high mutation rates, which is why there are so many different strains of
the flu virus. The body's own immune response has to work to rid the body
of the viral infection, if it can. The best medicine for viruses is preventative
medicine in the form of vaccines. Vaccines exist for some, but not all,
viruses. Vaccines are basically portions of the virus' protein coat, but
the virus itself has been deactivated by removing the genes that cause
the virus to enter cells and replicate. The immune system encounters the
"foreign" protein coat of the virus, tags it, records it, and stores it
in memory (so to speak). Later, if the immune system ever encounters that
specific viral protein, it recognizes it and launches an immediate immune
response. This is where antibodies and antigens come into play. Antigens
are proteins on the viral coat and antibodies are the host's counteractive
proteins that interact with the foreign antigens and stimulate an immune
Back to Main
Virus names and classifications, host ranges, plant viruses, etc.
for Molecular Virology
Comprehensive virology resource includes news, images and maps of viruses.
National Virus Reference Laboratory
The Virus Reference Laboratory provides a national diagnostic virology
service for Ireland, employing a wide range of methodologies for the identification
of viral infection in man and the determination of anti-viral immune status.
The VRL also provides information about viruses and the infections they
cause in Ireland and throughout the world. The VRL produces a regular bulletin,
Virus Alert and a weekly communicable disease report. The VRL will also
identify links to other WWW resources of virology, infectious disease and
epidemiology interest together with WWW resources of medical interest in
Ireland and throughout the world.
Virus Links on the Web