The main purpose of all organisms is to reproduce and survive, this is also true for viruses. Virus is a word that community members have heard a lot for a while, but what exactly is virus? The evolutionary history of viruses is a fascinating, if vague, topic for virologists and cell biologists. From a biological point of view, viruses are small microorganisms made up of DNA or RNA, even smaller than bacteria. This means that the genetic material carried by the virus can cause a wide variety of illnesses, from the common cold to more serious and longer-lasting illnesses such as HIV and AIDS. When it enters an organism such as a human, it seizes the genetic material of the virus, cells, allowing it to damage or alter them to proliferate rapidly. If the immune system can’t fight it, viral illness can be fatal. This article will cover how viruses can spread and how people can protect themselves from infections.
Classification of Viruses
Viruses are infectious agents of a small size and simple composition that can only multiply in living cells of animals, plants or bacteria. The true infectious part of viruses is their nucleic acid. Viruses carry either DNA or RNA, but cannot contain both. Because of the great diversity between viruses, biologists have struggled with how to classify these beings and relate them to the traditional tree of life. Viruses occupy a special taxonomic position. Viruses should not be regarded as organisms in the strictest sense because they do not live freely, ie they cannot reproduce and sustain metabolic processes without a host cell. Viruses are classified according to their nucleic acid content, size, shape of the capsid, and the presence of a lipoprotein envelope. Therefore, it is first divided into two classes: RNA viruses and DNA viruses. It is still customary to further divide viruses into three categories: those that infect animals, plants or bacteria.
Almost all plant viruses are transmitted by insects that feed on plants or other organisms (vectors). Hosts of animal viruses range from protozoa (unicellular animal organisms) to humans. Many viruses infect either invertebrates or vertebrates, and some infect both. Some viruses that cause serious illness in animals and humans are carried by arthropods. These vector-borne viruses reproduce in both the invertebrate vector and the vertebrate host. Some viruses appear to have adapted to grow only in ectothermic vertebrates (often called cold-blooded animals such as fish and reptiles) because they can probably only reproduce at low temperatures. The hosts of some other viruses are confined to endothermic vertebrates (usually warm-blooded animals such as mammals).
Many plant and animal species have their own viruses. For example, cats have feline immunodeficiency virus or FIV, which is a version of the HIV virus that causes AIDS in humans. Bats contain a different type of coronavirus that causes Covid-19. In addition, bacteria have a type of virus called bacteriophage. Viruses can combine with each other and mutate. This sometimes means that there may be changes in species such as COVID-19, which has been tackled in recent months.
Basic Structures of Viruses
Viruses are microscopic in nature, ranging in diameter from about 20 to 400 nanometers. In contrast, the smallest bacteria are about 400 nanometers in size. A virus consists of a single or double stranded nucleic acid and at least one protein surrounded by a protein layer called a capsid. The protein capsid provides protection for the nucleic acid and may contain enzymes that allow the virus to enter the appropriate host cell. Some viruses also have an outer lipid envelope. Covid-19 is such a virus. The use of soap can dissolve the lipid (oil) outer envelope, so the virus can be destroyed. That’s why washing hands with soap is so effective. Nucleic acid encodes genetic information unique to each virus and can consist of deoxyribonucleic acid (DNA) or ribonucleic acid (RNA). Some viruses, such as the poliovirus, have RNA genomes, and some, such as the herpesvirus, have DNA genomes. Viruses can only reproduce within a host cell.
Are Viruses Alive?
In 1898, Friedrich Loeffler and Paul Frosch found evidence that foot-and-mouth disease in livestock was caused by an infectious particle smaller than any bacteria. This was the first clue to the nature of viruses, genetic entities, that lie somewhere in the gray area between living and non-living. In order to answer the question of whether viruses are alive or not, it is necessary to understand what is meant by “life”. Although specific definitions may vary, biologists generally agree that all living organisms exhibit several key properties (the ability to grow, reproduce, maintain an internal homeostasis, respond to stimuli, and perform various metabolic processes). Additionally, populations of living organisms evolve over time. Viruses both meet and do not meet these criteria. In a sense, viruses have both living and non-living properties. Viruses are known to reproduce somehow. You can be infected with a small number of virus particles, for example, when a person coughs, the particles that are expelled are inhaled and then the person becomes sick after a few days while the viruses multiply in the body. Likewise, viruses evolve over time. For example, the flu vaccine should be administered every year because the flu virus changes or develops from one year to the next.
Viruses do not have a metabolism. In order to reproduce, they need the cells of other organisms because they cannot generate or store energy themselves. This means that they cannot perform any function outside of living cells, which is why viruses are often considered “non-living”. In addition, no virus has an organelle called ribosome, which is found in normal cells and where protein synthesis takes place. Viruses must use the ribosomes of their host cells to convert viral mRNA into viral proteins. Because of these limitations, viruses can reproduce only within a living host cell, ie they are obligate intracellular parasites, dependent on the host cell for almost all life-sustaining functions. However, not everyone dealing with science necessarily agrees with this conclusion. Perhaps viruses represent a different type of organism on the tree of life.
Reproduction of Viruses
Viruses are small microorganisms. They cannot reproduce independently due to their size and simplicity. Viruses depend on the host cells they infect in order to reproduce. When located outside of host cells, viruses exist as dormant particles (virions). While the virus in this form is outside the cell, it is not metabolically active. The development cycle of the virus begins when the nucleic acid of the particle called the virion and in some cases its proteins enter a sensitive host cell. For example, bacterial viruses bind tightly to the surface of the bacteria and then penetrate the hard cell wall, delivering the viral nucleic acid to the host. Animal viruses enter host cells through a process called endocytosis. Plant viruses, in contrast, enter through wounds in the outer layers of the cell, for example through wind-borne abrasions or through holes made by insects. Once the viral genome is inside the host cell, it usually directs the production of new viral components, producing new viral protein and new viral nucleic acid. In other words, an infected cell produces more viral protein and genetic material than its normal products.
These components are then assembled into whole virions (all virus particles containing nucleic acid contained in a protein capsule) that are discharged from the host cell. Virion (virion) is an inactive extracellular form of a virus. Virions cannot survive for long in inanimate environments outside of cells. If they come into contact with a cell, they can import their own genetic material, reproduce and infect organisms. When a virion attaches to a suitable host cell, it can penetrate the cell. When the virus gets inside, it takes over the cell to produce more virions. Virions usually exit the cell in this process by destroying the cell and increasing in numbers, then they begin to infect other cells they enter or capture.
How to Minimize the Pandemic Threat?
For example, when an influenza pandemic starts, it usually cannot be stopped because the virus spreads rapidly through coughing and sneezing. In fact, infected people can pass the virus to others even before symptoms appear. Preventing people from coming into contact with other people is one way to keep the flu from spreading. Generally speaking, the best way to avoid a viral infection is to stay away from sick people (this may mean staying home away from school or work and staying home from family members or roommates), washing hands regularly (correctly), touching the nose, mouth and face is to avoid. Apart from these, other things that can be done to prevent transmission of the virus are:
– For hand disinfection, an alcohol-based hand sanitizer should be used when soap and water are not available.
-If you need to go out while you are patient, a mask should be worn.
– Surfaces of the house and frequently touched items (including mobile phones) should be properly cleaned with disinfectants.
– If it is necessary to cough or sneeze, it should be done towards the elbow.
– Paper handkerchiefs or napkins should not be left around, they should be thrown into a closed garbage can.
– Hands should be washed after the nose is wiped.
– If there is a blood-borne virus, needles should not be shared.
– If the virus is sexually transmitted, a protective device such as a condom should be used during sex.
– The presence of the virus should be disclosed to others so that they can take action.
Providing vaccines to reduce the likelihood of developing the disease or using an antidote to treat after symptoms occur are other control tools. In order to make the body stronger and better equipped to fight viruses, general health should also be maintained. You should stay healthy by eating a balanced diet, taking the right vitamins and getting enough sleep. As long as all necessary preventive measures are taken to protect against viruses, there is no need to panic.
Reactions Against Viruses
Viruses cause a range of diseases in eukaryotes. In humans, diseases such as smallpox, colds, chickenpox, flu, shingles, herpes, polio, rabies, ebola, hanta fever and AIDS are examples of viral diseases. Even some types of cancer have been associated with viruses. There are several different ways an animal or human can react to a viral infection.
– Fever is a general reaction; many viruses are inactivated at temperatures slightly above the normal body temperature of the host.
– Secretion of interferon by infected animal cells is another common response. Interferon stimulates infected cells and their neighbors to produce proteins that interfere with virus replication.
Humans and other vertebrates can also organize an immunological attack against a particular virus. The immune system produces specially produced antibodies and sensitized cells to inactivate the infecting virus. These immune defenders circulate throughout the body long after the virus has been inactivated, thus providing long-term protection against reinfection of this virus. This long-term immunity is the basis for active vaccination against viral diseases. In active immunization, a weakened or inactivated strain of an infectious virus is introduced into the body. This virus does not trigger an active disease state but stimulates the production of immune cells and antibodies, which then protect against infection by the virulent form of the virus. Active vaccines are now routinely applied for viral diseases such as measles, mumps, polio, and rubella.
In contrast, passive immunization is the injection of antibodies from the serum of an individual who has already been exposed to the virus. Passive vaccination is used to provide short-term protection to people who have been exposed to viral diseases such as measles and hepatitis. It is beneficial if it is provided immediately after exposure, before the virus has spread widely in the body.
Treatment of Viral Infections
Historical definitions of viral diseases date back to the 10th century BC. However, the concept of viruses was not established until the last decade of the 19th century, when many researchers gained evidence that agents much smaller than bacteria can cause infectious diseases. The existence of viruses was proven when bacteriophages were discovered independently by researchers in 1915 and 1917. Bacteriophages are a favorite research tool of molecular biologists, as their genomes are small and can be prepared in large quantities in the lab. Bacteriophage studies have helped to elucidate such basic biological processes such as genetic recombination, nucleic acid replication and protein synthesis.
Treatment of an established viral infection is generally limited to the relief of specific symptoms; For example, fluid therapy can be used to control dehydration, or aspirin may be given to relieve pain and reduce fever. There are several medications that can be used to directly fight an infected virus. This is because viruses use the mechanism of living cells for replication; Drugs that inhibit viral growth also inhibit host cell functions. However, few antiviral drugs are available for certain infections.
The most successful controls on viral diseases are epidemiological. For example, large-scale active vaccination programs can break the transmission chain of a viral disease. Worldwide, vaccination is recognized for the eradication of smallpox, once one of the most feared viral diseases. Because many viruses are carried from host to host by insects or contaminated food, insect control and hygienic food handling can help eradicate the virus from certain populations.