Acquired Immunodeficiency Syndrome (AIDS) is a disease caused by the human immunodeficiency virus (HIV). 3-4 million new cases of infection are registered annually. Over the 25 years since the discovery of the virus, the disease has spread throughout the world. According to statistics, in 2006, more than 25 million died and 40 million people were infected with HIV (37 million are adults, more than 1/3 of them are women). In the United States, the first case of the disease was recorded in 1986. Currently, about 400 thousand people are living in the United States, but in reality, according to experts, they are from 800 thousand to 1.5 million people, which is 1-2% of the adult population country. All the measures that are being taken in the world to stop HIV infection do not bring results, although they may contain its spread.
Etiology and pathogenesis. HIV was discovered in 1983; it belongs to the family of RNA retroviruses, the subfamily lentiviruses (slow viruses).
Lentiviral infections are characterized by a long incubation period, poor symptomatic persistence against the background of a pronounced immune response and cause multiorgan lesions with inevitable death. HIV has a unique type of reproduction: thanks to the enzyme revertase, genetic information is transmitted from RNA to DNA (the reverse transcription mechanism). The synthesized DNA is inserted into the chromosomal apparatus of the affected cell. The target cells for HIV are immunocompetent cells, primarily T-lymphocyte helper cells (CD-4), since they have receptors on the surface that selectively bind to the virion. The virus also affects some B-lymphocytes, monocytes, dendritic cells, neurons. As a result of the defeat of the immune system, characterized by a sharp decrease in the number of T-helper cells, an immunodeficiency state arises, with all the ensuing consequences.
The only source of HIV infection is man. The virus can be isolated from blood, saliva, sperm, breast milk, cervical and vaginal mucus, tear fluid and tissues. The most frequent route of spread of the virus (95%) is unprotected both vaginal and anal sex. Adequate permeability of endometrial, vaginal, cervical, rectal and urethral tissues for HIV contributes to infection. The danger of anal sex is especially great because of the vulnerability of the single-layer epithelium of the rectum and the possible direct penetration of the virus into the blood. Homosexuals are one of the main risk groups for AIDS (70-75% of those infected). Sexually transmitted diseases increase the likelihood of HIV transmission due to damage to the epithelial layers of the urogenital tract.
The vertical transmission of HIV infection from the mother to the fetus is realized both as a result of transplacental transmission (during pregnancy) and with the help of the intranatal mechanism (during labor), and postnatally during breastfeeding.
Parenteral transmission of the virus through infected blood or its components is possible, with the transplantation of organs and tissues, with the use of non-sterile syringes and needles (often among drug addicts).
Proved the impossibility of HIV infection through normal household contacts, insect bites, food or water.
Clinical picture. Young people (30–39 years old) usually prevail among those infected. Clinical manifestations are determined by the stage of the disease, concomitant infections.
In the initial stages, half of those infected have no symptoms. Approximately 5-6 weeks after infection, an acute phase develops in 50% of patients with fever, general weakness, night sweats, lethargy, loss of appetite, nausea, myalgia, arthralgia, headache, sore throat, diarrhea, lymphadenopathy, diffuse maculopapular rash, peeling of the skin, exacerbation of seborrheic dermatitis, recurrent herpes.
Laboratory primary infection can be confirmed by ELISA or by determining specific antibodies (IgG, IgM), as well as DNA and RNA in PCR. Antibodies usually appear in the blood 1-2 months after infection, although in some cases they are not detected even for 6 months or more. Regardless of the presence or absence of symptoms, patients during this period can be a source of infection.
The stage of asymptomatic carriage of HIV can last from several months to several years and begins regardless of the febrile stage in the past. There are no symptoms, but the patient is contagious. Antibodies to HIV are detected in the blood.
In the stage of persistent generalized lymphadenopathy, the lymph nodes, especially the cervical and axillary, are enlarged. Possible candidal lesions of the mucous membranes of the oral cavity, chronic persistent candidiasis of the vagina with a duration of up to 1 year or more.
The stage of development of AIDS (the stage of secondary diseases) expresses a crisis of the immune system, an extreme degree of immunodeficiency, which makes the body defenseless against infections and tumors, usually safe for immunocompetent individuals. Serious opportunistic infections come to the fore, the spectrum and aggressiveness of which is growing. Increases propensity for malignant tumors. Pneumocystis pneumonia, cryptococcosis, recurrent generalized salmonellosis, extrapulmonary tuberculosis, herpes infection, etc. are attributed to AIDS-related infections. Secondary infections together with tumors determine a wide range of AIDS clinical manifestations involving all tissue systems in the pathological process. At the last stage of the disease, there is a long-term (more than 1 month) fever, significant weight loss, damage to the respiratory organs (Pneumonia, tuberculosis, cytomegalovirus infection), damage to the gastrointestinal tract (candidal stomatitis, chronic diarrhea). Patients have neurological disorders (progressive dementia, encephalopathy, ataxia, peripheral neuropathy, toxoplasmic encephalitis, brain lymphoma), skin manifestations (Kaposi’s sarcoma, multifocal shingles).
Life expectancy after the first signs of AIDS do not exceed 5 years.
The diagnosis of HIV infection is made on the basis of prolonged fever, weight loss, swollen lymph nodes, and AIDS-related diseases.
Laboratory diagnostics consists in detecting virus-specific antibodies by ELISA. With a positive result, conduct an immunochemical analysis. Additionally, you can use PCR. Antibodies to HIV must be determined in patients with inpatient treatment, in pregnant women, donors, in patients at risk, in workers in a number of professions (doctors, workers in commerce, children’s institutions, etc.), therefore, the diagnosis of HIV infection is established in the early stages. or clinical manifestations. Immunological studies allow to assess the degree of immunosuppression and monitor the effectiveness of the treatment. For this purpose, the number of T-helper cells is determined, as well as the ratio of T-helper / T-suppressors (CD4 / CD8), which steadily decreases as the disease progresses.