The Nature of Viruses and Their Contribution to Virusogenesis

For more than 100 years, the scientific community has been debating over what viruses are. First recognized as mindless life-formals, then as mere poisons, viruses today are often considered to be in a grey area between purely living and non-living: they are neither life-form nor non-life-form but may only effect other living things. They are, however, important to the ecosystem as they provide an important service – replicating themselves. This service serves many purposes, including the prevention of disease and the spread of disease-causing organisms. Furthermore, some viruses do their damage by damaging vital protein structures within living cells such as the ribosome in the cell’s protein engine. These protein structures are essential to life and without them, the cell cannot function properly.

Because some viruses may have a viral origin, there are various types which exist and the way in which they spread is dependent on the type and their specific characteristics. There are well known and well documented instances in which the virus itself may spread from one organism to another. These include retroviruses which are responsible for some forms of cancer. Some viruses may even act like normal molecules or cells for a brief period before exploding off into their own microscopic world and spreading infection.

The majority of viruses that infect living organisms either use one of their genetic materials ( RNA or DNA) to divide into larger and more dangerous organisms or use the DNA as a template for creating more copies of themselves (strands) by replicating themselves within the host’s genome. While some viruses may use only one method of duplication, others (such as the bacteria tobacco mosaic virus or the Epstein-Barr virus) use all three. Additionally, some viruses may use just one type of DNA but use an entirely different method of replication to spread their genetic material.

Since the methods by which a virus replicates and spreads can vary, it is often difficult to determine whether a virus is infectious or not. Viruses can infect living organisms by means of bacteria, fungi and other microorganisms which require a living host. A virus that causes a disease, such as the herpes simplex virus or the Epstein-Barr virus, spreads by the introduction of the virus into a host’s body, but since the exact mechanism by which this occurs is unknown, it is not certain whether the disease is caused by the virus or the spread of the virus. It should be noted that any disease caused by a virus is considered to be potentially infectious even if the disease was not introduced by a living host. For instance, the hepatitis B virus, which is responsible for the majority of cases of chronic hepatitis in the developed world, can easily spread between individuals through blood transfusions and infected injection needles, but it is unclear whether transmission via these methods is actually necessary.

To better illustrate how important it is to distinguish between the different types of viruses infecting different host cells, let’s consider a relatively simple example: bacteria. A bacterium known as pseudomonas aeruginosa, for example, infects bacteria which are present in our bodies (monocytes) and later causes a reaction within those monocytes which causes them to multiply into inflammatory cells which are commonly found in inflamed gingivitis. However, it is still not clear whether the bacterium actually causes an infection or whether it simply reacts with the body’s immune defenses. If, for instance, we were to observe that Pseudomonas was able to multiply and attach itself to a blood vessel, we would then have strong evidence that Pseudomonas is an agent that causes an infection – and therefore, strong evidence that it is infectious.

Similarly, with respect to viruses, it is difficult to distinguish between small viral particles which are not yet identified as viruses, and larger, unidentified particles which may be viruses. The fact is that these larger particles are capable of multiplying into infectious agents, and they can be identified through laboratory tests. However, because the structure of DNA and its coding is such that it is very difficult to decipher, even by experts, many scientists agree that a virus which utilizes a genetic material to code can be considered to be “self-replicating” in nature. It is possible that this is the case with all viruses.