Friday, January 24, 2014

Aliens among us!

A little departure from my usual blogs this week - It seems like I am surrounded by people with all manner of viruses! - I have become a compulsive hand washer.  So let me remind you, that if you haven't done it yet - its not too late to get a flu shot to protect your self!

So If you will humor me -  the biology teacher in me feels a need to remind you all about viruses.    I keep running into people with incorrect ideas about what viruses are and how they operate... so here goes...

Virus particles are like something out of science fiction. They come in all configurations; some look like lunar landing modules, others like spikey balls, or three dimensioned geometric forms.  The virus particles are not technically "alive" - but contain only a protein coat and on the inside carry one strand of genetic information. 

A phage style virus

Once inside the body they attach to the outside surface of their target cells and release a protein enzyme to create an opening in the cell membrane through which they are able to pass a single strand of genetic material  (usually DNA, but some viruses are designed to use RNA instead).  This strand of genetic information  carries instructions  to stop the normal operations of the cell and take command of the cells resources.  Another portion of the DNA strand now begins to organize the production of component parts for thousands of duplicate virus particles.  The DNA strand has information then for assembly of the component parts. 

Stages in the cycle of virus production in a host cell

The final action of the DNA is the production of an enzyme that causes the invaded cell to burst open releasing the virus particles - each one ready to attack another cell and continue the invasion of the body.  There are some variations on this theme that cause a slow production of virus particles by the invaded cells and do not involve the breaking open of the cell under attack.  These cells can recover after the illness.

A human sneeze is an ideal mechanism for spreading viruses - Imagine one good sneeze can contaminate an entire room... Yuck!

Colds, flu, HIV, rabies, polio, measles, mumps, herpes, hepatitis, chicken pox/shingles are all caused by virus infections.   Plants are also victims of virus diseases.  When you get a virus what does the doctor tell you - "Get plenty of rest, drink lots of fluids, and let your body recover.  A wag commented that if you keep working with a cold it may take seven days to recover, however if you stop and take it easy you will recover in a week".  The recovery is easier if you rest...and you won't share the virus with all of your colleagues.  I hate to tell you this - but medicine or medical treatments are not normally used in treating our virus diseases - that is left up to our bodies to do on their own.  

Electron Microscope image
 Viruses are incredibly smaller than even bacteria

Your body's natural response to a virus is to activate an immune response. Our bodies use the invaders to create shape specific antibodies molecules for each different virus disease. Antibodies are like a lock and key that, when matched with the virus particles can "lock" or neutralize the viruses so they can no longer enter or damage our cells. To neutralize each different strain of organism, the antibodies must have the right pattern to match the characteristics of each virus.

A typical cold virus - recreation based on electron micrograph images

 The antibodies collected in our body remember each virus pattern that has caused an immune response in the past.  We fool the body into making antibodies by injecting weakened or dead virus particles into the body (an inoculation) - your body will respond by making antibodies without actually getting sick. in some cases similar viruses can stimulate the production of antibodies similar enough to casue protection.  

When the first inoculations against small pox were offered, many refused to take them- even to avoid that dread disease... The refusal then reminds me of people today who say that they dont believe in getting flu shots

The classic case if the small pox inoculation that gives us one "cow pox" on our arm and ever after we are protected from the much more severe small pox disease.   If this virus invades you in the future your antibodies will protect you from disease.  The inoculation causes us to quickly make up a lot of the antibodies.   If it is a new invading virus (or a disease for which you do not have a shot),  usually our body can make antibodies that can match just right in a week to ten days.... but you feel the symptoms of the disease until this happens.  Most antibodies stay in your body for years.  But in some cases you may need a "booster shot" to maintain an adequate number.

Another vector host that we all know way too well - Mosquitos are responsible for many times more human deaths than all the sharks and rattlesnakes in the worlds

Colds and flu are highly adaptable and keep evolving new patterns.  So each year a new blend of the expected flu strains are used in creating a flue vaccine for those varieties - hence a new shot is recommended every year.  Imagine what a soup of antibodies you carry in your blood.  But viruses come in such a variety that its possible to get sick from something for which you do not have antibodies.

If you get a cold and go to the doctor saying, "Please doctor give me an antibiotic so that I can get better faster!" Forget it.  Doctors know that antibiotics only work against bacteria. They have absolutely no effect on viruses.  All you can do is treat the symptoms to feel better.  It all comes down to chicken soup and aspirin!

The relative size of particles, bacteria, viruses