Sometimes, when they get sick with ARVI or the flu, people rush to the pharmacy for an antibiotic, not realizing that they cannot cure a viral disease. After all, an antibiotic is a medicine aimed at suppressing pathogenic bacteria, but not viruses. Only antiviral drugs can help with the latter.
Bacteria and viruses are microscopic organisms that can cause disease in both humans and animals or plants. While bacteria and viruses may share some characteristics, they are also very different. Bacteria are usually much larger than viruses and can be viewed with a conventional microscope. Viruses are about 1000 times smaller than bacteria and are visible only under an electron microscope. Bacteria are single-celled organisms that reproduce independently of other organisms. Viruses need the help of a living cell to reproduce.
It is noteworthy that the virus is much smaller than bacteria. Therefore, they are able to pass through an antibacterial filter. The size of the virus varies from several tens to three hundred nanometers. They are not available for microscopic examination through light equipment. It was this for a long time that prevented them from being detected even when examining tissues of infected organisms.
Viruses penetrate into cells and begin their destructive activity. The human immune system produces antibodies that are sent in search of the evil parasite. Only now, neither antibodies nor leukocytes, due to their enormous size, can penetrate the membrane of the membranes of human cells. Usually, the connective tissue, where the microbes are located, is well washed by the blood, and the presence of it in the body saturated with antibiotics helps to instantly cope with them.
Viruses enter a cell of a living organism or a bacterium and force organelles (ribosomes) of the cell to synthesize viral proteins, from which multiple copies of the virus are then assembled. When viruses leave the cell, its death most often occurs. New viruses invade other cells at high speed. This is how the virus makes the body work for itself. So, in fact, the infection progresses.
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The virus either destroys the host cell or provokes an immune system response, which manifests itself with symptoms such as fatigue, fever, and even severe tissue damage.
If you visually imagine a huge house of 20-25 floors, then a small box of matches that fell from a window sill is the ratio of the size of a microbe and a virus. Therefore, it is easy for them to parasitize, function, feeding on the cytoplasm, while not damaging its outer cells. Some even use microbes in their food, such viruses are also called phagocytes.
The immune system, like many other physiological systems, is made up of molecules, cells, tissues, and organs. The main organ of the immune system is the thymus gland, or thymus, an organ located behind the breastbone that produces special cells, the most important cells of the immune system.
- In fact, these are cells-regulators and cells-soldiers, and this army stands to protect our body. But she needs to be prepared to meet the virus. The formation of immunity takes from two weeks to three months after vaccination. Therefore, it is better to do it not the day before, but before the estimated time of the epidemic.
The cells of a vaccinated person are prepared and trained to fight the virus, unlike the cells of an unvaccinated person. They secrete antibodies that block the virus. The profiled cell knows which particles need to be produced in order to block a particular virus. Therefore, the body must be prepared for a possible meeting with the virus - immunize with a vaccine containing antigens.
Thus, the structure of the virus suggests a parasitic lifestyle that microorganisms need to protect themselves from the environment. Although viruses move freely enough in space from one host to another. Therefore, they pose a high risk of epidemics of those diseases where viruses are the causative agent.
The tobacco mosaic virus infects not only tobacco plants, but also the fruit fly that feeds on it. Thus, by prolonging the life of the fly and its fertility (benefiting), the virus harms the plants;
A virus that infects a fungus that grows in grass near geothermal springs allows the plant to survive in elevated temperatures. It is beneficial for the viral organism to preserve the host in places that are difficult to exterminate, where the temperature reaches 50 degrees Celsius;
Some viruses protect the host from other viral agents entering and reproducing in the body. The virus protects its territory and in some cases does not cause significant harm to the owner to preserve the place of residence.
Interestingly, over time, such viruses become not so much parasites as part of the organism itself. Therefore, it begins to be passed on from generation to generation and is determined by the genetic code as a useful property that is subject to transmission. Thus, the virus retains its place and endows the host organism with new properties for survival.
Viruses can also be transmitted from sick animals. Eating contaminated meat or close contact with infected individuals is often the cause. Although there are viruses that are not able to be transmitted between species. Such microorganisms are relatively safe for humans and other animals. Most often, a person becomes infected by eating meat from cattle and poultry. But viruses are known that are spread by wild animals, for example, pigeons. In addition, the bites of infected mammals transmit the rabies virus and others.
A person can transmit a viral infection in different ways. Depending on the localization of the pathogen and the characteristics of the disease, the following transmission routes from person to person are distinguished:
Airborne. This type of transmission is inherent mainly in viruses that affect the respiratory system. The virus is in the air and is transmitted to a potential host at the time of inhalation of infected air masses;
Sexual. Many viruses are localized on the mucous membranes, then affecting the entire body. Often, such parasites enter the body of a healthy person during sexual intercourse. However, even using a condom may not always protect against infection. Wet kisses can also cause infection;
Hematogenous. This happens during the transfusion of infected blood. Most often this happens during an emergency transfusion, when the blood does not undergo a proper check with a mandatory storage period;
Domestic. In some cases, the virus can be transmitted through personal belongings or contaminated secretions of the patient's body that come into contact with damaged skin. A number of viral hepatitis and AIDS can be transmitted in this way, although it is believed that the probability of infection in this case is relatively low.
Some viruses also require surgery to remove the infection. In particular, representatives of molluscum contagiosum or papillomatous formations (HPV) must be removed surgically. After removal, immunomodulatory therapy is performed, which is aimed at restoring the protective functions of the body. Any virus is dangerous because it causes suppression of the immune system, exposing the body to the danger of contracting any disease. This is especially true for HIV. Therefore, it is so difficult to deal with it and maintain the patient's vitality.
Viruses surround us and can invade our body. Becoming parasites, they begin to take away the resources of the human body and slowly kill us. Therefore, it is important to take precautions and get vaccinated on time. This is especially important for those who, by profession, have a lot of contact with people who may be infected with any viruses.
Due to the possibility of transmission of the virus, even by air or through mucous membranes, you should strengthen your health and avoid dubious contacts. Promiscuous sex and close interaction with a sick person can lead to infection. In this case, a person may not even know that he has a disease, and lead the most ordinary way of life. Therefore, it is better to always be careful in communication, as well as take care of yourself and your loved ones.
The virus multiplies rapidly, eating the cytoplasm of the cells, soon it does not get enough of it, and it breaks through the cell membrane, is immediately attacked by antibodies. But if immunity has fallen, then a doctor may recommend a drug effect, for example, the use of immunoglobulin. Then it is easier to kill the virus with blood with active substances, especially when they have already remained unprotected and left human cells. Acyclovir, viramune, epivir, remantadine and other drugs are successfully used in antiviral therapy. It is for this reason that viruses are useless to treat with antibiotic therapy.
The "Achilles heel" of any virus is an uncontrolled multiplication that causes rupture of the cell membrane of its "shelter". And everything seems to be fine at first it enters the cell, soon multiplies and breaks out into the blood, where it is washed off with antiviral drugs.
But the whole difficulty lies in the fact that more than ninety percent of the viruses in the human body are located in the cells, and there they cannot be killed or obtained. That is, in fact, drugs cannot kill them, but for now antibodies and globulins are synthesized inside the body, especially if a person has weak immunity for a long time. During this period, the virus can do enough harm to the body. Scientists are concerned about the vulnerability of our bodies to the viral nature of diseases.
Bacteria: Bacteria are prokaryotic cells that display all the characteristics of living organisms. Bacterial cells contain organelles and DNA that are immersed in the cytoplasm and surrounded by a cell wall. These organelles perform vital functions that allow bacteria to receive energy from the environment and reproduce.
Viruses: Viruses are not considered cells, but exist as particles of nucleic acid (DNA or RNA) enclosed in a protein envelope. Also known as virions, viral particles exist somewhere between living and non-living organisms. Although they contain genetic material, they do not have the cell wall or organelles needed to produce and reproduce energy. Viruses rely solely on the host cell for replication.
While most bacteria are harmless, and some are even beneficial to humans, other bacteria can cause disease. The pathogenic bacteria that cause disease produce toxins that destroy cells in the body. They can cause food poisoning and other serious illnesses, including meningitis, pneumonia, and tuberculosis.
Bacterial infections can be treated with antibiotics, which are very effective at killing bacteria. However, due to the overuse of antibiotics, bacteria have gained resistance to them. Some of them even became known as superbugs because they gained resistance to many modern antibiotics. Vaccines are also helpful in preventing the spread of bacterial diseases. The best way to protect yourself from bacteria and other germs is to wash your hands correctly and often.
Viruses are pathogens that cause a number of diseases, including chickenpox, influenza, rabies, Ebola, Zika, and HIV / AIDS. Viruses are capable of causing persistent infections in which they are dormant, and can be reactivated later. Some viruses cause changes in host cells that lead to cancer. These viruses are known to cause cancers such as liver cancer, cervical cancer, and Burkitt's lymphoma. Antibiotics don't work against viruses. Treatment for viral infections usually involves medications that treat the symptoms of the infection, not the virus itself. Typically, the immune system fights viruses on its own. Vaccines can also be used to prevent certain viral infections.
Some of the viruses are so changeable that the immune system simply does not have time to develop a reliable response against them - antibodies against viral proteins become outdated very quickly and do not see new, changed viral particles. Others pass under immune "radars" with the help of unwitting allies. For example, the polio virus enters the body with the help of intestinal microflora: the immune system perceives symbiotic bacteria as friends, while viruses use bacterial cells as a cover, making them invisible to defense systems. Finally, since the signal of danger is transmitted in immunity through a number of molecular-cellular "instances", you can simply wedge into the signal chain and, figuratively speaking, cut the wire.
This is exactly what adenoviruses do, which we owe to acute respiratory and intestinal infections, conjunctivitis, etc. The DNA of adenoviruses is packed in a complex with a protein called protein VII. It helps to fold, compact the viral genome so that it fits in a small viral particle - in fact, protein VII performs the same function as histones in our cells, without which our DNA would simply not fit into any cell nucleus.
There is no cure for a viral infection? In fact, they are. Most antiviral drugs work through one of three mechanisms.
The first is to stimulate the body's own defenses to fight the virus. This is how, for example, "Arbidol" and "Cycloferon" act.
The second is a violation of the structure of new viral particles. Drugs of this kind are altered analogs of nitrogenous bases that serve as material for the synthesis of nucleic acids. Due to structural similarities, they are incorporated into the DNA or RNA of the virus multiplying in the cells, making new viral particles defective, unable to infect new cells. An example of such a drug is acyclovir, which is used to treat herpes infections.
The third mechanism is to prevent the virus from entering the cell. The drug prevents the viral DNA or RNA from detaching from the protein coat, due to which the genetic material of the virus loses its ability to penetrate the cell membrane. This is how rimantadine works, for example.
All of the above drugs act only on actively multiplying viruses.
In recent years, attempts have been made to generate gene therapy for viral infections, that is, to fight viruses with the help of … viruses. For this, the genome of a suitable virus (such a virus is called a vector) is modified. First, it is deprived of its disease-causing properties. Secondly, a sequence of genes is added to it, which, when interacting with the genome of the virus targeted for treatment, "turns it off". After that, the vector with the genes is introduced into the human body suffering from a viral infection. This treatment is still under development and confirmation of its efficacy and safety, but it is hoped that gene therapy for viral infections will become available in the coming years.
In addition, there are viruses that selectively attack bacterial cells. They are called bacteriophages (literally "bacteria eaters"). There have been many attempts to use them to fight bacterial infections, but they have not shown significant advantages over antibiotics. Bacteriophages are used in genetic engineering to deliver the required genetic material to bacterial cells.
