Causes of AIDS and its forms

The causes of AIDS are those factors that aggravate the course of HIV infection. Immunodeficiency Syndrome is the final stage of HIV infection. From the moment of infection to the development of the terminal form, it takes from 2 to 15 years on average. Dozens of factors influence the speed of AIDS. An infected person may not face the terminal stage of the disease. Among the "positive" patients since the early 2000s, the number of AIDS-related deaths is gradually decreasing. But eliminating the causes that provoke it remains the basis for preventing and improving the lives of those infected.

AIDS development

HIV infection is a slow-flowing disease, since the moment of infection the patient may be unaware of his status for decades. The whole cycle of the disease is divided into five phases, the last of which is AIDS. How it develops: the virus enters the human blood and embeds its RNA into the DNA of immune cells. On the surface of the virus, there is a protein that is able to bind to another CD4 protein. This protein is on the shell of our immune cells, it allows the pathogen to be fixed in the human body.

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

Primary manifestations are followed by a latent current, when pathogens do not manifest themselves at all. At this point, HIV is "preserved" in our body. If you detect the infection at the early stages and start treatment, 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 cause of the development of AIDS is a low immune status.

Why immunity decreases with HIV. Lymphocytes die from the action of the pathogen, when attacking T-killers or self-destruct as unnecessary and dangerous. Whatever way the cells die, it leads to a decrease in immunity. With a weak protective function, a person is not able to overcome even elementary infections. Gradually, HIV infection progresses to AIDS - its final phase.

From the moment of infection to the advent of the terminal stage, an average of 2-15 years passes. AIDS develops at different speeds, the "time margin" depends on the patient's condition, quality of treatment, lifestyle. Today, competent therapy allows you to extend the life of HIV-positive and keep it working. But the treatment is still difficult to call public because of the high cost, so many rely on prevention.

Factors accelerating the transition to the stage of AIDS

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

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

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

Factors that accelerate the onset of AIDS:

  • lack of treatment;
  • initially weakened health;
  • bad habits: drugs, alcohol, smoking;
  • mental instability: neurosis, stress, depression;
  • low income and life;
  • poor nutrition;
  • advanced age.

Using highly active antiretroviral therapy (HAART), the probability of dying from AIDS is reduced by 85.1-99.3%.

Also, the rate of infection and the onset of the last stage is influenced by genetics. CXCR4 and CCR5 co-receptor mutations prevent the virus from entering the cell. This does not completely protect against infection, but prevents the rapid development of AIDS. But there are some mutations that accelerate this process. For example, with different changes in the HLA antigen, the probability of a rapid onset of AIDS increases up to 6 times.

It used to be that HIV progressed faster in women and girls than in 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 women are more likely to have HIV. The speed of the onset of the last stage is influenced by the patient's age: this happens most quickly in infants and the elderly. This is directly related to the ability of immunity to resist infection of new cells. And in the case of the older age group, it is also important that they develop 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 on the background of immunodeficiency. Such infections are called opportunistic, they are caused by conditionally pathogenic microorganisms. 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. People with AIDS have practically no “barrier”, so the diseases are more severe. In addition to conditionally pathogenic microorganisms, parasites, bacteria and viruses from the outside cause complications of AIDS.


Tuberculosis is 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, it affects not only the lungs, but also other organs, which is possible only with immunodeficiency.

Streptococcus pneumoniae is the cause of bacterial pneumonia, which is found in HIV-positive. Typical symptoms: prolonged cough, fever, shortness of breath and chest pain. It is treated with a set of antibiotics in the hospital. Also from bacteria in AIDS, staphylococci are dangerous, they affect the skin, hair follicles, internal organs and the mucous membrane.

The gastrointestinal tract is “attacked” by salmonellosis and shigellosis, the main symptom of which is long-term diarrhea, weakness, nausea.


A pulmonary form of AIDS is a condition where the most associated diseases fall on the respiratory system. In addition to mycobacteria, the lung infects the fungus Pneumocystis jirovecii or pneumocystis. This is the cause of one of the most common opportunistic infections - Pneumocystis pneumonia. Symptoms: shortness of breath, prolonged cough, chest pain, fever, sweating, especially at night.

Self-medication is strictly not allowed. 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 the fungi of the genus Candida, they exist 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 brain membrane, which threatens with complications and death. Typical symptoms for meningitis: photophobia, fever, headaches, heaviness in the back of the head, impaired consciousness.


Viruses affect the nervous system, internal organs, brain, skin. One sign of weakened immunity is the development of shingles. Pathogen - Varicella zoster or varicella zoster virus. For many people, this pathogen “sleeps” after having had chickenpox in childhood. Against the background of HIV, herpes zoster flows with abundant rash, suppuration, pain. Requires long-term treatment.

Cytomegalovirus affects any organs and systems, most often:

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

The most dangerous infection of the retina, as this leads to blindness. Viral pneumonia occurs typically with cough, fever, and shortness of breath. Symptoms of cytomegalovirus in the intestine: diarrhea, abdominal pain, weakness, fever. Antiviral drugs Foscarnet, Gantsiglovir showed the best treatment.

A rash on the skin causes a molluscum contagiosum virus. Infection occurs through contact with the pathogen carrier. At infection on any site of skin rash with white contents appears. When combing or skin damage, the rash spreads to adjacent areas. Even with immunodeficiency special treatment is not required. Symptoms disappear within a few weeks or months.


Fungi, bacteria and viruses cause complications more often than parasites. But the “encounter” with the latter leads to opportunistic diseases. Cryptosporidium - the causative agent of intestinal infections, intracellular parasite. Cryptosporidia cause diarrhea, which can last months or even years. When cryptosporidiosis diarrhea is established for more than 1 month, HIV-positive patients are diagnosed with AIDS. The effect of the parasite leads to a strong weight loss, due to a violation of the absorption of nutrients, which is deadly without treatment.

Isosporosis is a disease caused by the simplest parasites Isospora belli and Isospora natalensis.

As in the case of cryptosporidia, leads to the depletion of the patient. Pathogens multiply in the epithelial cells of the intestine, disrupting its function. Abdominal pain and weakness are added to diarrhea. The treatment is inpatient, and effective provided an early start.

Parasites can attack not only 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 concentrating. Without treatment, the infection progresses rapidly and leads to coma and death. Toxoplasma sometimes affects the heart, genitals, and lungs.

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

It does not matter what stage is HIV-positive, the way of infection is the same for any phase. Methods of transmission of the pathogen are well studied, and the dissemination of this information should reduce the increase in the infected. The virus is transmitted:

  • through blood;
  • during unprotected sex;
  • during childbirth and childbirth;
  • when breastfeeding.

To infect the patient's biological fluid must enter the body of a healthy person. The causative agent is in saliva, secretions of the genital organs, semen, blood, urine. But each fluid has a different amount of virus, so their infectious ability varies. For example, for transmission through 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 in the viral load: the larger 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, the infection is impossible without the penetration of biological fluid into a healthy person.

Blood-to-blood contact

In the early years of the spread of the epidemic, a huge number of people were infected through blood transfusions. Such fear has remained until now, although today it is not justified. Blood-to-blood transmission can occur when transfusing or using non-sterile instruments with particles of infected blood. Any donor blood has long been tested for viruses, and for HIV in the first place.

Most of the instruments in medical institutions are disposable, and not disposable, undergo disinfecting treatment.

So far, the most common route of transmission of the virus through the blood is injecting drugs. The use of non-sterile syringes takes up almost half of all infections. Insects and mosquitoes do not carry the infection from the patient to the healthy.

Perinatal contact and breastfeeding

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

The risk of infection increases after the departure of amniotic fluid and at the time of delivery. WHO statistics for the African Region show that about half of newborns are infected during natural childbirth. Another 20% take the virus through breast milk. Therefore, expectant mothers are prescribed ART to reduce viral load, cesarean section, and artificial feeding. Women and girls in the stage of AIDS is not recommended to become pregnant. The amount of pathogen is too high, and the health of the lady is very weak.

Sexual contact

The first person “suspected” of spreading the epidemic is sex. Initially it was believed that only homosexuals can get HIV, time has shown that everyone can get infected. The scientific journal “The New England Journal of Medicine” published observations in this matter. 124 couples were tested, where one was HIV-negative and the second was positive. For 20 months, discordant couples led a normal life, some of them practiced sex without protection, others used condoms.

According to the results of studies in couples where contraceptives were not used at all, 15% of the "negative" participants became carriers of HIV. Scientists assumed that this number will be more. Nevertheless, the massive surveillance of WHO shows that the virus is transmitted during any type of sex, and this mode of transmission accounts for 70-80% of all cases.

Does the condom protect

Latex protects against HIV because the virus does not penetrate the structure of the material. The same study with 124 pairs proved this. Among those who used condoms correctly and not a single healthy partner was constantly 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 transmitting the virus when using male contraceptives is less than 2%.

Survival of HIV in the environment

Under laboratory conditions, it is established that the pathogen can live for 1-3 days in the external environment as part of the dried liquid. But in such studies the concentration of the virus is used 100,000 times higher than it happens in natural conditions. In life, HIV as part of any liquid dies in a few minutes in the open air, as it does not withstand oxidation. He dies at high temperatures, from the action of alcohol and disinfectors.

Ultraviolet rays do not kill the virus. In needles and syringes, the pathogen retains its viability for several days. It depends on the storage temperature, the amount of blood in the needle or syringe, the viral load.Cases of domestic infection are not registered, as well as infections through swimming pools, public transport, general dishes. The use of ART reduces the number of pathogens, thereby reducing a person's ability to transmit the infection.

Article author:
Izvozchikova Nina Vladislavovna

Specialty: infectious diseases specialist, gastroenterologist, pulmonologist.

Total experience: 35 years.

Education: 1975-1982, 1MMI, San gig, high qualification, infectious diseases doctor.

Science degree: doctor of the highest category, PhD.


  1. Infectious diseases.
  2. Parasitic diseases.
  3. Emergency conditions.
  4. Hiv
Other author articles

Watch the video: Medical Animation: HIV and AIDS (February 2020).