Fri | Jul 21, 2017

What is a virus?

Published:Tuesday | October 7, 2014 | 10:00 AM
This photo provided by the Centres for Disease Control shows an Ebola virus.

A VIRUS is a tiny infectious agent that only multiplies inside the living cells of other creatures. The experts still debate whether viruses are really living and have described them as "organisms at the edge of life". Viruses are everywhere. For example, a single teaspoon of sea water contains about one million viruses and they are vital to the health of the marine environment.

The word itself comes from the Latin 'virus', referring to a poison or harmful substance. Viruses are found wherever there is life and have probably existed from when living cells appeared. The study of viruses is called virology, and is a science important to the understanding of how cells function. However, because of their minute size, scientists were only able to see them after the invention of the electron microscope. Viruses are about a thousand times smaller than bacteria and it could take up to three quarters of a million viruses lying side by side to stretch to one centimetre.

Unlike the cells in the human body, viruses do not have the chemicals (enzymes) necessary for life. Instead, a virus must have a host cell in which to live. When a virus infects a cell, the virus forces it to make thousands more viruses. But outside of a host cell, viruses cannot function.

Viruses can infect all types of life forms including animals, plants and bacteria. An infection with a virus can cause disease. Examples of common human diseases caused by viruses include warts, the common cold, influenza, chickenpox, and cold sores as well as dengue and the currently infamous chikungunya. Many other more serious diseases like Ebola, AIDS, bird flu, and SARS are also caused by viruses. Viruses are also known to cause cancers in humans, like cervical, liver and blood cancers.

Prevention and treatment

Because viruses make use of host cells to reproduce, they are difficult to kill without using drugs that have toxic effects on the host cells as well. The most effective conventional medical approaches to viral diseases have been public health strategies. These include lifestyle and behavioural changes to control transmission of the virus and vaccinations to create immunity to infection.

In my opinion, basic public health measures have played a more useful role than modern technology. Like all of nature, viruses are smart and have an amazing ability to change their structure (mutate) to make vaccines ineffective. The common cold and flu viruses, for example, are constantly changing into new strains so that each season, new cold and flu 'shots' are needed.

Vaccines were used to prevent viral infections long before the discovery of the actual viruses. Their use has resulted in a dramatic decline in illness and death associated with certain viral infections such as polio, measles, mumps, rubella and smallpox. Vaccines are currently used to prevent viral infections in humans and animals.

Many unconventional physicians, like myself, consider vaccines to be a potentially dangerous two-edged sword that should not be used with the current wild disregard to their dangers.

Vaccines can consist of live or dead viruses or viral parts. Live vaccines contain weakened forms of the virus, which should not cause the disease, but only confer immunity. But live vaccines can be dangerous when given to people with a weak immunity because the weakened virus can actually cause the original disease. By their very nature, vaccines have powerful effects on the immune system that are not all good.

The immune system

The body's first line of defence against viruses is the immune system. The immune system is a network of cells, tissues, and organs that work together to defend the body against attack. You can think of the immune system as the body's security force. The healthy immune system recognises and responds to foreign substances and agents, including viruses, by destroying or deactivating them. The immune defences normally coexist peacefully with the body's healthy cells. When functioning well, the immune system has a remarkable ability to distinguish between the body's own cells, recognised as 'self' and abnormal cells, germs and substances, or 'nonself'.

The organs of the immune system include white blood cells, the lymph nodes, the bone marrow, thymus gland and spleen. Lymphoid tissue are also found in the linings of the digestive and respiratory tracts and include familiar structures like the tonsils, adenoids, and the appendix.

Anything that triggers the immune system to response is called an antigen. An antigen can be a germ, such as a virus, a cancer cell or an alien chemical like a vaccine. In response to an antigen, the immune system produces special substances to neutralise or destroy offending antigens. These are called antibodies.

When an individual's immune system is underactive, his defences are low and he becomes prone to diseases like infections and cancers. HIV/AIDS is a classic example of a hypoactive immune system disorder because this virus suppressed immune function.

Allergic disorders occur when the immune system responds to a false alarm. In an allergic person, normally harmless material such as grass pollen, food particles, mould, or house dust mites is mistaken for a threat and attacked. Here, the immune system produces antibodies to these relatively benign things. When the immune system mistakes its own healthy tissues (self) for the enemy (nonself) and launches an attack against itself, autoimmune diseases occur like lupus, rheumatoid arthritis, thyroid disorders, type one diabetes or scleroderma, to name just a few. Their conditions can be very challenging for doctors to treat, but, fortunately, there are many things that we can do to keep the immune system healthy and functional.

It is interesting and, in my opinion, certainly not coincidental that the alarming increase in immune system disorders in modern societies has mirrored the increase in viral disorders and the ongoing promotion of more and more vaccines for more and more conditions.

You may email Dr Vendryes at or listen to An Ounce of Prevention on POWER106FM on Fridays at 8:15 pm. Go to for information on his new book.