The term HIV stands for human immunodeficiency virus, which is the causative agent of AIDS. The pathogen affects the body's defense system, as a result of which it cannot function normally and impede the development of various ailments. Currently, it is impossible to get rid of the causative agent of HIV, all treatment methods are aimed only at slowing the reproduction of the virus. This allows patients to significantly extend their life.
Main characteristics
The causative agent of HIV infection was discovered at the end of the twentieth century (in 1983). The virus was discovered simultaneously by two scientists from the United States and France. 2 years before the discovery of the pathogen in America, acquired immunodeficiency syndrome, known as AIDS, was first described. It has now been found that the causative agent of HIV has two types. The first is common in European countries and the United States, the second - in West Africa.
Information on the origin of the pathogen is extremely scarce. To date, the main hypothesis is that it says that the causative agent of HIV infection was formed due to mutations in monkey viruses. He appeared on the territory of Africa, where he became widespread. For many years he did not go beyond the borders of the country, hitting an increasing number of indigenous people. The development of the territories of Africa was gradually taking place, as a result of which the rate of migration flows increased and contacts were established with some states. A logical consequence was the widespread spread of the pathogen.
Key characteristics of the causative agent of HIV infection:
- Refers to retroviruses. This family is characterized by the presence of a genetic apparatus represented by ribonucleic acids.
- The virus is a spherical particle. Its sizes can vary from 80 nm to 100 nm.
- The causative agent of HIV consists of a protein coat, nucleic acid and a special enzyme. The latter promotes the conversion of virus RNA into pathogenic DNA. After this, it is introduced into the human macromolecule, which is responsible for the implementation of the genetic program.
The disease can proceed in different ways. Sometimes it develops rapidly, more often - it stretches for several years. Supportive therapy can increase the patient's life expectancy. The absence of treatment inevitably leads to death in a shorter time.
Viability
The causative agent of HIV infection is a pathogen that can develop only in the cells of other organisms. The virus exhibits an extremely low degree of resistance in the external environment. It can multiply exclusively in the human body.
The causative agent is resistant to low temperatures, its vital activity does not stop even when frozen. Neither ultraviolet nor ionizing radiation have any effect on it. In this case, the causative agent of HIV infection is a pathogenic microorganism that instantly dies when boiled. If the temperature is slightly lower, his life stops after about half an hour.
In addition, the pathogen quickly dies under the influence of 70% alcohol, acetone solution, 5% hydrogen peroxide, ether, chloramine. When dried, the virus remains viable for up to 6 days. In a heroin solution, all the properties of the pathogen persist for about 3 weeks.
Life cycle phases
He is very complex. The life cycle of the HIV pathogen consists of several stages:
- In the blood of a person circulating cells - T-lymphocytes. On their surface are receptor molecules. The virus binds to them and penetrates into T-lymphocytes, while the pathogen discards the protein coat.
- There is a synthesis of a copy of DNA. This process is carried out due to the presence of reverse transcriptase enzyme in the virus.
- Formed copy of DNA is introduced into the cell nucleus. There is the formation of a ring structure. After that, it is embedded in the macromolecule of the carrier.
- A copy is stored in human DNA for several years. In this case, the infected person may not feel any warning signs. The presence of a copy of DNA can be detected in the blood of a person randomly, for example, during a routine examination.
- When a secondary infection enters the body, the process of synthesis of viral RNA starts.
- The latter also produces pathogenic proteins.
- From newly synthesized substances, new pathogenic particles begin to form. Then they exit the cell, which usually dies.
In the above phases of the life cycle is the mechanism of transmission of the causative agent of HIV infection.
Immune System Impact
The body's defenses are designed to neutralize and destroy externally delivered antigens. Foreign viruses include all viruses, bacteria, fungi, protozoa, pollen, yeast, and even donated blood.
The immune system is represented by cells and organs that are located throughout the body. T-lymphocytes are responsible for the formation of the reaction. It is they who initially determine that the causative agent of the disease (HIV infection) is an antigen. After recognition of a foreign element, T-lymphocytes start the synthesis of a number of substances that accelerate the maturation of new protective cells. After this, the production of antibodies occurs, the main task of which is the destruction of pathogenic microorganisms.
But the virus is able to quickly penetrate into T-lymphocytes, due to which the body's defenses are weakened. Immunodeficiency develops. Often, HIV is present in the body, but the infected person does not even suspect it. The inactive period is from 1 year to 5 years. At the same time, a small amount of antibodies that have developed the immune system circulate in the blood. It is their presence in the liquid connective tissue that is the basis for the diagnosis.
As soon as the virus enters the bloodstream, a person is considered its carrier, that is, he can infect others. In this case, the only symptom, as a rule, is an increase in some lymph nodes.
Over time, the virus activates, it begins to multiply very quickly and destroy T-lymphocytes. In other words, one of the main links of the defense system is destroyed. At the same time, the body, when various pathogens enter it, waits for a signal from T-lymphocytes about the beginning of the formation of an immune response, but it does not arrive. Thus, a person becomes defenseless even against commonplace infectious diseases that do not pose a danger to healthy people.
The progression of immunodeficiency is accompanied by the formation of tumors. Over time, the brain and nervous system are involved in the pathological process.
Transmission ways
The source of infection is always a person (and for many years suffering from AIDS, and the carrier). According to the basic theory of pathogen origin, wild chimpanzees are the first type of HIV reservoir, and African monkeys are the second. In this case, the remaining animals are immune to infection.
The main epidemiological danger is represented by the following types of biological material of a person:
- blood;
- vaginal secretion;
- sperm;
- menstrual flow.
The smallest threat is: saliva, breast milk, cerebrospinal fluid, lacrimal secretion.
Key HIV transmission pathways:
- Natural (during sexual intercourse, from mother to child during fetal development or during the delivery process). The risk of infection after a single sexual relationship is very small. It increases significantly with regular sexual intercourse with the carrier. From mother to child, the virus is transmitted through defects formed in the placental barrier, when the baby comes into contact with blood during delivery or with breast milk. According to statistics, the incidence rate among newborns is approximately 30%.
- Artificial (with the parenteral route of administration of drugs, transfusions, medical procedures that are traumatic, etc.). One of the main ways of transmitting the HIV causative agent is through injecting with needles that are contaminated with the blood of a person suffering from AIDS or carrying the virus. Also, infection often occurs during medical procedures that violate sterility standards: tattoos, piercings, and dental procedures.
The causative agent of the disease (HIV) is not transmitted through contact-household transmission.
Cases have been recorded when a person was found to be immune to the virus. Scientists believe that this is due to the presence of specific immunoglobulins that are present on the mucous membrane of the genital organs.
Symptoms
The development of immunodeficiency is slow. During the course of HIV infection, it is customary to distinguish several stages:
- Incubation. Its duration is from 3 weeks to several months. The stage is characterized by intensive reproduction of the virus, while the immune response from the body is still absent.
- Primary manifestations. The formation of the immune response is accompanied by intensive production of antibodies. At this stage, disturbing signs may not appear. But most infected people have the following symptoms: fever, rashes on the skin and mucous membranes, swollen lymph nodes, diarrhea, pharyngitis. In some patients, the acute stage is accompanied by the addition of secondary infections (tonsillitis, fungal pathologies, pneumonia, herpes, etc.). In this case, signs of emerging ailments are added. The duration of the stage of primary manifestations is about three weeks.
- Latent. It is characterized by the progression of immunodeficiency. In this case, the only symptom is only an increase in lymph nodes. The duration of the stage varies from about 2 to 20 years.
- Stage of secondary diseases. The patient’s body weight decreases, working capacity decreases, and his health worsens. In severe cases, secondary infections acquire a generalized form.
- Terminal stage. At this stage, disorders caused by the development of secondary diseases are irreversible. Moreover, any treatment methods are ineffective. This stage is fatal.
HIV infection is characterized by a diverse course, that is, some stages may be completely absent. The duration of the development of the disease is from several months to many years.
Diagnostics
The causative agent of HIV infection refers to retroviruses. To identify them, the most commonly used method is ELISA or PCR. Sometimes the doctor additionally prescribes a laboratory test using the immune blotting method. In the process of diagnosis, the specialist has the ability to identify antibodies to HIV, which is the basis for making an accurate diagnosis.
Treatment
All conservative methods of therapy are aimed at slowing the progression of the disease and preventing the development of secondary infections.
Typically, an HIV treatment regimen includes the following items:
- Taking medications of antiretroviral action. The active substances of the drugs help to reduce the rate of reproduction of pathogens. Such drugs include the following: Zidovudine, Zalcitabine, Abacavir, Nevirapine, Ritonavir, Nelfinavir, etc.
- Reception of vitamins and dietary supplements.
- Physiotherapy.
- Strict adherence to the regime.
- Diet.
- Psychological help.
It is important to understand that the advisability of taking certain drugs is evaluated only by a doctor. Immunostimulants for HIV infection are not prescribed. This is due to the fact that such drugs contribute to the progression of the disease.
It is important to treat secondary pathologies in a timely manner. If the patient suffers from drug addiction, he must be placed in an appropriate inpatient facility.
Forecast and Prevention
It is impossible to get rid of HIV. In this regard, the decisive role is played by the determination and psychological state of the patient. Previously, patients lived, on average, 11 years after infection. At present, a large number of modern drugs have been created, an effective regimen of maintenance therapy has been developed. If you strictly follow the doctor’s instructions, the life span is significantly increased and can be several tens of years.
The main preventive measures are: avoidance of accidental sexual contacts, timely treatment of sexually transmitted infections, visits to medical institutions that only value their reputation, and regular medical examinations.
Special attention is currently being paid to sexual illiteracy. In order to rectify the situation, many schools and universities include special courses in the curriculum.
Finally
HIV is the causative agent of AIDS, but the infection can develop over the years. It is introduced into T-lymphocytes upon penetration into the body, due to which the functioning of the immune system is disrupted. As a result, a person becomes helpless even in the face of a commonplace cold.
If an ailment is detected, the patient must follow the rules of maintenance therapy for life, otherwise there is an acceleration of the onset of a fatal outcome.
The main preventive measure is the elimination of accidental sexual relations. In addition, it is not recommended to visit dubious medical facilities for traumatic procedures.