Viruses are one of the main causes for illnesses in the world. It is vital that everybody knows the basic information about how to prevent spreading them and how vaccines work. This is so that more and more people will end up going and taking the vaccines and so less people will end up dying from the diseases.
Viruses are living/non-living (there is a heated debate on this!) organisms that take control of host cells and then use them to their own advantage.
After taking the host, the virus will reproduce and consequently kill the cell it inhabited, bursting it, and releasing the many new viruses which go on to infest even more cells.
Their structure is far simpler than that of a bacteria.
The Simple Virus Structure
All About Viruses
Viruses cause many of the illnesses that we commonly face. Measles, chicken pox, cold sores and the flu are caused by viruses. Plant diseases such as tobacco mosaic virus, as the name suggests causes the mosaic disease in tobacco plants.
Viruses (and bacteria) that cause disease are called pathogens. Pathogens can affect both animals and plants.
They are simply a strand of nucleic acids, either DNA or RNA. This strand is enclosed in a protein coat. This DNA can be either a single or a double strand of DNA.
Sometimes viruses are found with what are known as ‘outer envelopes’. They makes this outer layer by using the membrane of the cell that they infest. HIV is an example of a virus which makes one of these envelopes for itself.
It is important to know that viruses cannot reproduce by themselves. They lack the vital organelles necessary to do so. As a result, a virus has to infest a host cell in order to replicate, using the host cell’s metabolic processes instead of it’s own . Once a virus attaches to the host cell, it injects it’s nucleic acid into it, which then replicate and form their own protein coats.
The nucleic acids have now become the same as the original virus cell that attached to the cell in the first place and when the cell dies (cell lysis) they release and infest other host cells. Repeating the process.
A Diagram of Viruses at Work.
How A Virus Actually Works
A virus is a very simple thing with a very simple purpose.
- It attaches to the membrane (outer part) of a host cell
- It injects it's own DNA/RNA into the cell, leaving behind it's protein coat
- The host cell's nutrients are used by the viral DNA/RNA to produce more DNA/RNA
- All of the new DNA/RNA takes nutrients from the cell to make new protein coats inside of the host cell
- The host (usually) dies, releasing the countless amounts of progeny that were produced within it
- Each virus then goes on to find a new host cell and processes 1-6 repeat.
As a result of it's relatively small size & simple structure (which means only a small amount of nutrients will suffice to reproduce) and fast reproduction rate, viruses evolve very quickly to their environments.
The flu virus for example has no permanent vaccine because the virus changes so rapidly that the vaccine soon becomes obsolete. This is said to happen when the antigens that the virus used to have (which the vaccine targeted) are no longer recognisable. The antigens become so different that they are no longer recognisable by a body which knew the old antigens from the old vaccine.
As a result of this we are advised to take a new flu vaccine every year.
Doing this will slowly reduce some forms of flu and reduce the amounts of flu available to mutate and evolve. Thus, slowly, the flu virus may be eradicated from the planet.
Preventing them from spreading
Here are the common ways in which viruses spread:
- Coughs and sneezes
- Touching (handshakes, high fives etc.)
- People eating infectious food (e.g. food touched by dirty hands)
- Exchange of body fluids (blood, semen, saliva)
Ways in which we can help prevent the spread of viruses in respect to the above points:
- Coughing and sneezing into tissues and binning them, actively avoiding other people whilst doing so
- Washing our hands frequently with antibacterial hand wash and taking notice of other people's hygiene habits (although be careful about not shaking your boss' hand on the premise that you think it might be dirty, perhaps just wash your hands afterwards)
- Making sure we know where our food has been before eating it and not eating food that we know has been touched by other people who's hands were not clean.
- Not having unprotected sex, stopping the transmission of diseases through semen (and blood!) This is particularly important in the prevention of sexually transmitted infections (STI's) such as the HIV virus.
- Using insect repellants such as sprays, bug zappers and high frequency sound tools will reduce the risks of contracting and subsequent spreading of insect borne diseases. Putting up anti-insect nets such as mosquito nets will prevent them from reaching us whilst we sleep, resulting in less chances of mosquito's surviving and so less mosquito's to spread the disease.
- Vaccines work for all of points 1-5 too because they prevent the actual damage of viruses occurring, letting the body kill the virus and ending the cycle by which viruses spread, reproduce and spread again.
More on Vaccination
- Vaccines most commonly contain inactive forms of pathogens.
- They can however contain weakened forms of active pathogens.
- Some even use small parts of the pathogen in the vaccine - so that antigens on the surface of the parts will enter the bloodstream and provoke the primary immune response.
We have had success in eradicating viruses from many countries who have had the resources to do so. Naturally, the eradication of viruses is in everyone's interest as it means that less people will die, less medical costs will be present and more work can be done.
The two main ways of eradicating a virus are:
- Vector Control (killing the organism by which a pathogen is spread) - In many countries, using tools such as insecticides (anti insect chemicals) in the form of sprays, bug zappers and mosquito nets has resulted in the reduction and death of mosquito's. Thus a significant or total reduction of the diseases mosquito's carry were reduced. These diseases include: Malaria (not a virus but a protist), Yellow Fever, Dengue Fever, Japanese B encephalitis and West Nile Virus.
The USA is one country which has eradicated malaria using vector control.
- Vaccines - vaccination is the process of injecting an organism (for example a human) with an inactive or weak form of a pathogen (disease causing microorganism, for example a virus), so when that organism is attacked by an active version, it will already have antibodies (defense against the disease) to fight off the disease quickly. Without a vaccine, it can take 10-17 days to produce the necessary antibodies, which by that time, damage will most likely already have been done (if not death). Thus, vaccinating large populations means that the virus is quickly handled and killed off before it is able to spread to even more people. It doesn't have the chance to reproduce in us and spread to those around us.
Interesting Fact: Babies are born with over 100 million different antibodies already in their bodies so that they can fight off a wide variety of different diseases efficiently.
For More information about how the HIV spreads and how to stop it
- How does HIV spread?
Vital information about how to stop the rapid spread HIV, a deadly and serious threat to humanity.
For information about the other main type of disease causing organism: Bacteria. As well as it's uses - Read
- The Uses Of Bacteria
Important information about what makes a bacteria, what use they have in the world and the dangers of them.
DK (author) from London on December 13, 2012:
Thanks for the input Phriot, I'll research and make the amendments you provided :)
Viruses I know have been disputed concerning their status as a living organism - but I felt that since they were capable of evolving (even if it is with the help of host cells) they should be classified as living?
Thanks by the way,
phriot on December 13, 2012:
Hi Philanthropy! I liked your overview on viruses, but have a few suggestions. First, you classify viruses as an "organism," which is defined as something that carries out all the processes of life. There is some debate of whether or not viruses are "alive," so this might cause some confusion to your readers. Second, not all vaccines use inactivated microorganisms, some use just pieces that can be recognized by the immune system and others even use intact, but weakened forms of the virus or microorganism.
Thanks for writing this Hub!
DK (author) from London on June 14, 2012:
Thank you very much! :)) Glad people are learning from it!
C E Clark from North Texas on June 14, 2012:
Lots of good information here that everyone should know. Remember learning about this in one of my science classes, but it was good to review again here. Your explanations were very clear, which is what they need to be if you hope to reach non-science people and actually instruct us. I do love science. Voted you interesting and useful. Excellent hub!
HSAdvocate from Home on June 09, 2012:
Good hub very informative. Just two criticisms from a biology teacher. The picture you have is of a T4 bacteriophage which only infects bacterial cells not eukaryotic cells like in humans, and malaria while transmitted by mosquitoes is not a virus, it is a protist. There are some very cool animations of viruses here-http://www.hhmi.org/biointeractive/disease/animati...
Rhys Baker from Peterborough, UK on December 27, 2011:
Fabulous hub. Scientific, concise, with real-world implications. You didn't dumb it down either. Thanks for sharing