Causes of AIDS and its forms

Causes of AIDS are those factors that exacerbate the course of HIV infection. The immunodeficiency syndrome is the final stage of HIV infection. From the moment of infection to the development of the terminal form, an average of 2 to 15 years passes. Dozens of factors influence the rate of development of AIDS. An infected person may not experience the terminal stage of the disease. Among "positive" patients since the early 2000s, the number of deathsassociated with AIDS has been gradually decreasing. But the elimination of the causes that provoke it remains the basis for the prevention and improvement of the lives of those infected.

The development of AIDS

HIV infection is a slow-moving disease, from the moment of infection, the patient may not be aware of his status for decades. The entire cycle of the disease is divided into five phases, the last of which is AIDS. How it develops: The virus enters the human bloodstream and inserts its RNA into the DNA of immune cells. There is a protein on the surface of the virus that can bind to another CD4 protein. Such a protein is on the shell of our immune cells, this allows the pathogen to gain a foothold in the human body.

Penetrating into the cell, the pathogen integrates into DNA. From now on, not only those cells that contain HIV will be infected, but also their copies. Such a “cunning” of the virus has not yet allowed scientists to find cures and stop the pandemic. In the first 3-6 months after infection, antibodies to HIV are produced, this period is called the incubation period. This is followed by a phase of primary manifestations, when the patient develops symptoms similar to other infections.

Primary manifestations are followed by a latent course, when pathogens do not manifest themselves at all. At this point, HIV is “conserved” in our body. If the infection is detected early and treated, the asymptomatic phase can be extended for many years. But even in "sleep mode", the disease continues to reduce the number of our CD4 cells: microglia, macrophages, T-helpers, etc. The reason for the development of AIDS is a low immune status.

Why immunity decreases in HIV. Lymphocytes die from the action of the pathogen, when attacked by T-killers, or self-destruct as unnecessary and dangerous. No matter how the cells die, this leads to a decrease in immunity. With a weak protective function, a person is not able to overcome even elementary infections. So gradually HIV infection progresses to AIDS - its final phase.

From the moment of infection to the appearance of the terminal stage, an average of 2-15 years passes. AIDS develops at different rates, the "time margin" depends on the patient's condition, quality of treatment, lifestyle. Today, competent therapy allows you to prolong the life of an HIV-positive person and maintain his working capacity. But the treatment is still difficult to call generally available because of the high cost, so many rely on prevention.

Factors accelerating the transition to the AIDS stage

Two independent studies in Sweden and San Francisco showed that without treatment, only 3% of patients do not experience the stage AIDS. In all other cases, death occurs in this phase.

Death usually occurs due to a series of infections that the body cannot cope with even with therapy. Antiretroviral therapy, a healthy lifestyle and mental stability help to delay the moment of the terminal stage and even completely eliminate it.

An unambiguous diagnosis of AIDS is made when the level of CD4 cells drops to 200 units per cubic millimeter of blood. For comparison, in healthy people this indicator averages 500-1500 units. In addition to low immune status, the person must have opportunistic diseases. These are pathologies that the body copes well with in the normal state, but with HIV infection they lead to serious complications.

Factors that accelerate the onset of AIDS:

  • no treatment;
  • initially weakened health;
  • bad habits: drugs, alcohol, smoking;
  • mental instability: neurosis, stress, depression ;
  • low income and living standards;
  • poor nutrition;
  • advanced age.

With the use of highly active antiretroviral therapy (HAART), the likelihood of death from AIDS is reduced by 85.1–99.3%.

Genetics also influence the rate of infection and the onset of the final stage. Mutations in the co-receptors CXCR4 and CCR5 prevent the virus from entering the cell. This does not completely protect against infection, but prevents the rapid development of AIDS. But there are also mutations that speed up this process. For example, with different changes in the HLA antigen, the likelihood of a rapid onset of AIDS increases up to 6 times.

Women and girls were previously thought to progress faster with HIV than men. Large-scale studies in Switzerland have shown that in women, the immune status decreases with a lower viral load than in men. But this does not mean that HIV is faster in women. The rate of onset of the last stage is affected by the age of the patient: it occurs most quickly in infants and the elderly. This is directly related to the ability of the immune system to resist infection of new cells. And in the case of the older age group, it also matters that they produce new CD4 lymphocytes more slowly.

Causes of complications

By itself, the pathogen does not kill a person, death occurs from the addition of other infections against the background of immunodeficiency. Such infections are called opportunistic, they are caused by opportunistic pathogens. On the mucous membranes and skin of people there are always a number of bacteria and fungi that do not lead to complications due to the protective function of the body. In people with AIDS, the “barrier” is practically absent, so the diseases go in a more severe form. In addition to opportunistic pathogens, AIDS complications are caused by parasites, bacteria and viruses from the outside.

Bacteria

Tuberculosis is the most important for HIV-positive people. According to WHO estimates, with a combination of immunodeficiency and tuberculosis, the mortality rate reaches 90%. The causative agent of the disease is mycobacterium. In severe cases, not only the lungs are affected, but also other organs, which is possible only with immunodeficiency.

Streptococcus pneumoniae is the cause of bacterial pneumonia that occurs in HIV-positive people. Symptoms are typical: prolonged cough, fever, difficulty breathing and chest pain. He is treated with a set of antibiotics in the hospital. Staphylococci are also dangerous among bacteria in AIDS, they affect the skin, hair follicles, internal organs and mucous membranes.

The gastrointestinal tract is "attacked" by salmonella and shigella, the main symptom of which is prolonged diarrhea, weakness, nausea.

Fungi

Pulmonary AIDS is the condition where most associated diseases attack the respiratory system. In addition to mycobacteria, the lungs are affected by the fungus Pneumocystis jirovecii or pneumocystis. This is the cause of one of the most common opportunistic infections, pneumocystis pneumonia. Signs: shortness of breath, prolonged cough, chest pain, fever, sweating, especially at night.

Self-medication is strictly prohibited. In the laboratory, the fungus is first isolated from sputum, then therapy is prescribed. The cause of pneumonia associated with AIDS can be other fungi: histoplasm, aspergillus, cryptococcus. Most of the “troubles” are caused by fungi of the genus Candida, they are in the body of every person, and with AIDS they easily get out of control. Candidiasis can appear on any organ, most often it is genital, oral, bronchial and in the gastrointestinal tract. At the terminal stage, there is disseminated candidiasis, when several organs or systems are affected at once.

A dangerous disease - meningitis, causes cryptococcus. The pathogen affects the lining of the brain, which threatens complications and death. Typical symptoms for meningitis : photophobia, fever, headaches, heaviness in the back of the head, impaired consciousness.

Viruses

Viruses infect the nervous system, internal organs, brain, and skin. One of the signs of a weakened immune system is the development of shingles. The causative agent is Varicella zoster or chicken pox virus. In many people, this pathogen "sleeps" after having chickenpox in childhood. Against the background of HIV, shingles occurs with a profuse rash, suppuration, and pain. Long-term treatment is required.

Cytomegalovirus affects any organs and systems, most often:

  • lungs;
  • nervous system;
  • retina;
  • intestines;
  • lymph nodes.

The most dangerous infection of the retina, as it leads to blindness. Viral pneumonia proceeds typically, with cough, fever, shortness of breath. Symptoms when cytomegalovirus enters the intestines: diarrhea, abdominal pain, weakness, fever. Antiviral drugs Foscarnet, Ganciclovir showed themselves best in the treatment.

Skin rash is caused by molluscum contagiosum virus. Infection occurs through contact with a pathogen carrier. When infected, a rash with white contents appears on any part of the skin. When combing or damaging the skin, the rash spreads to neighboring areas. Even with immunodeficiency, special treatment is not required. Symptoms go away on their own within a few weeks or months.

Parasites

Fungi, bacteria and viruses are more likely to cause complications than parasites. But the “meeting” with the latter also leads to opportunistic diseases. Cryptosporidium is a causative agent of intestinal infection, an intracellular parasite. Cryptosporidium causes diarrhea that can last for months or even years. If cryptosporidiosis diarrhea is established for more than 1 month, an HIV-positive person is diagnosed with AIDS. The influence of the parasite leads to severe weight loss due to malabsorption of nutrients, which is fatal if left untreated.

Isosporiasis is a disease caused by the protozoan parasites Isospora belli and Isospora natalensis.

As in the case of cryptosporidium, leads to exhaustion of the patient. Pathogens multiply in the epithelial cells of the intestine, disrupting its function. Diarrhea is accompanied by pain in the abdomen, weakness. Treatment is inpatient and effective if started early.

Parasites can attack more than just the intestines. Toxoplasmosis affects the central nervous system. This is a dangerous condition that can threaten with paralysis, psychopathy. At the first stages, patients have headaches, decreased performance, difficulty in concentrating. Without treatment, the infection progresses rapidly and leads to coma and death. Sometimes Toxoplasma affects the heart, genitals, lungs.

Modes of infection from a patient in the last stage of HIV

No matter what stage the HIV-positive person has, the routes of infection are the same for any phase. The modes of transmission of the pathogen are well understood, and the dissemination of this information should reduce the increase in infections. The virus is transmitted:

  • through the blood;
  • during unprotected sex;
  • during childbearing and childbirth;
  • while breastfeeding.

For infection, the patient's biological fluid must enter the body of a healthy person. The causative agent is found in saliva, genital secretions, semen, blood, urine. But each liquid has a different amount of virus, so they have different infecting ability. For example, for transmission through the blood, one drop is enough, and through saliva, an exchange of 2 liters of saliva is needed.

The difference between a person with HIV and an AIDS patient is the viral load: the higher it is, the easier it is to infect another person. Therefore, in the terminal stage it is easier to infect others. But even in this case, without the penetration of biological fluid into a healthy person, infection is impossible.

Blood-to-blood contact

In the early years of the epidemic, a huge number of people were infected through blood transfusions. This fear has remained to this day, although today it is not justified. Blood-to-blood transmission can occur through transfusion or through the use of non-sterile instruments containing infected blood particles. Any donated blood has long been tested for viruses, and for HIV in the first place.

Most of the instruments in medical institutions are disposable, and devices and instruments for reusable use are disinfected.

By far the most common route of transmission of the virus through the blood is through injecting drugs. The use of non-sterile syringes accounts for almost half of all infections. Insects and mosquitoes do not carry the infection from sick to healthy.

Perinatal contact and breastfeeding

A child can become infected with HIV in the following three cases: during pregnancy, during childbirth, while breastfeeding. But the baby may not get infected. Despite the mass of cases of the birth of healthy babies, HIV-positive women are advised to think carefully and take full responsibility before pregnancy. During pregnancy, an infant can become infected through careless invasive examination.

The risk of infection increases after the amniotic fluid breaks and at the time of delivery. WHO statistics for the African Region show that about half of newborns become infected during vaginal delivery, and another 20% become infected with the virus through breast milk. Therefore, expectant mothers are prescribed ART to reduce the viral load, caesarean section and artificial feeding. Women and girls in the AIDS stage are not recommended to become pregnant. The amount of the pathogen is too high, and the health of the woman is significantly weakened.

Sexual contact

The first person "suspected" of spreading the epidemic was sex. Initially, it was believed that only homosexuals could get HIV, time has shown that everyone can get infected. The New England Journal of Medicine has published observational data on this issue. 124 couples were tested, where one was HIV negative and the other positive. For 20 months, discordant couples led a normal life, some of them practiced sex without protection, others used condoms.

In studies of couples who did not use contraceptives at all, 15% of “negative” participants became HIV carriers. Scientists assumed that this number would be higher. However, massive WHO surveillance shows that the virus is transmitted through any type of sex, and this mode of transmission accounts for 70-80% of all cases.

Does a condom protect?

Latex protects against HIV because the virus does not penetrate the structure of the material. The same study with 124 couples proved it. Among those who used condoms correctly and consistently, not a single healthy partner became infected. Another scientific journal, the Journal of Acquired Immune Deficiency Syndromes, published the results of observations of couples where one is HIV negative and the other is positive. Heterosexual partners were tested.

The risk of virus transmission when using male contraceptives is less than 2%.

Survival of HIV in the environment

In laboratory conditions, it was found that the pathogen can live 1-3 days in the external environment as part of a dried liquid. But such studies use a concentration of the virus 100,000 times higher than it occurs naturally. In life, HIV in the composition of any liquid dies in a few minutes in the open air, as it does not withstand oxidation. The virus dies at high temperatures, from the action of alcohol and disinfectants.

Ultraviolet rays do not kill the virus. In needles and syringes, the pathogen remains viable for several days. It depends on the storage temperature, the amount of blood in the needle or syringe, and the viral load. No cases of domestic infection have been registered, as well as cases of infection through swimming pools, public transport, and common utensils. The use of ART reduces the amount of the pathogen, thereby reducing the person's ability to transmit the infection.

References
  1. World Health Organization. – HIV/AIDS.
  2. BBC NEWS Ukraine. – Where, when and why did AIDS appear?
  3. State Budgetary Institution of Health of the Arkhangelsk Region "Konoshskaya Central District Hospital". – Information about HIV/AIDS.