Since 1981, the pathogen is known that causes HIV and AIDS. Researchers now assume that the HI virus has been at fault since the beginning of the 20th century, originating from a type of virus transmitted from monkeys to humans. While around 3, 000 new infections were reported in Germany in 2015, more than 36 million people worldwide are infected with HIV.
Although HIV is now treatable, a means of healing is not yet in sight. Many sufferers live after infection with the HI virus for several years without major complaints, until AIDS breaks out.
HIV weakens the immune system
At the beginning of the 1980s, reports of patients with similar symptoms became more frequent: they suffered from many diseases that are normally warded off by the immune system of healthy people. Thus, severe pneumonia or unusual cancers such as Kaposi's sarcoma occurred.
In 1982, the disease got its name: AIDS, the abbreviation for "Acquired Immune Deficiency Syndrome" (acquired immunodeficiency syndrome). By this time, she had already been diagnosed in 14 countries.
Three years later, it was able to find the triggering virus, a year later it was baptized "Human Immunodeficiency Virus" (HIV). Thousands of people were already known worldwide and many of them already died.
With the discovery of the virus, the hope was hoped to soon have found a treatment. But it was not until the mid-90s that combined therapy was developed - it helped but did not heal. Since then, research has made great progress; however, no cure has been found to date. But at least the quality of life and expectancy of HIV sufferers is many times better than in the early days.
Transmission of the HI virus
The HI virus, researchers suggest, is a relative of the simian immunodeficiency virus (SIV) that infects chimpanzees and monkeys. Presumably, the virus has been transmitted to humans through the consumption of monkey meat, where it has become HIV.
The retro-virus is transmitted from person to person via the mucous membranes through the exchange of body fluids (blood, sperm, vaginal fluid, breast milk), especially in unprotected sexual contact, by the common use of syringes or (especially in the early days) by contaminated blood,
Theoretically, there is also a risk of infection during oral or tongue kissing, but today the risk is estimated by the scientists to be virtually zero. Shaking hands, hugging, sharing dishes, bath or toilet are harmless. The virus only survives outside the human body for a short time.
HIV - often no symptoms and symptoms for a long time
The HI virus attaches to a protein (CD4 protein) of certain body cells, infiltrates the cell and hides there in the DNA, the "memory" for the human genome - this process is also referred to as "reverse transcription", In the host DNA, it can stay undetected for a long time. This is also the reason why many infected people do not know about their illness for months or even years.
HIV uses the host cell to copy its own genetic information over and over again, to produce new proteins and to cut them together to create a new virus. This can decouple itself from the host cell and break into new cells, also infecting them and thus potentiating the described cycle.
Since particular body's own defense cells have the protein CD4, to which the virus docks, especially these helper lymphocytes are affected by the virus invasion. This in turn leads to the typical signs of the onset of AIDS, the full picture of HIV infection: symptoms caused by diseases that the immune system is not working properly. The affected defense cells are namely destroyed or can no longer fulfill their tasks, since their power plants are abused by the viruses for their reproduction.
Course of HIV infection
The course of an HIV infection is divided into three sections with different symptoms:
- Primary phase
- latent phase
- AIDS stage
Primary phase with flu-like symptoms
After a primary infection, the symptoms only appear a few days to weeks after the virus has been transmitted and last up to 2 weeks. They are often mistaken for flu because of general fatigue, fever, night sweats, loss of appetite, and lymph node swelling and rash.
In this phase, the viruses in the blood multiply extremely fast, which means that the infected is very contagious.
Latency phase - number of viruses drops
During the latency phase, the defense system first tries to cope with the virus invasion. The number of viruses ("viral load") in the blood drops massively. The affected people sometimes live for years, without feeling any symptoms. However, HIV is not idle, but is multiplying continuously.
Therefore, the number of CD4 helper cells gradually decreases, so that the performance of the immune system steadily decreases. If the infection is not detected and the virus is not contained with medication, the HIV infection goes into the AIDS stage.
AIDS stage: opportunistic infections
The AIDS stage is characterized by "opportunistic infections", ie infections by bacteria, fungi or viruses, which hardly cause illness in healthy people. For example, pneumonia caused by Pneumocystis carinii (PCP) or toxoplasmosis of the brain are typical.
In the blood this stage of the immunodeficiency shows by the decrease of the CD4 cells and the increase of the virus number.
Treatment of HIV
Even if the HIV infection still can not be cured, with an early start therapy, the onset of the AIDS stage can be prevented or at least delayed for years. Therefore, even with the slightest suspicion of a possible infection, an HIV test makes sense - even if there are no symptoms.
Therapy with antiretroviral drugs (antiretroviral therapy / ART), a vaccine is still not in sight. Drug therapy can intervene at various points in the viral cycle. For optimal effect different active ingredients (usually at least three) are combined.
Thus, the virus is prevented from entering the cell, its incorporation into the host DNA by reverse transcriptase is hindered in various ways, and protein production is inhibited for the copying and cutting of the viral genome. Further points of attack are in the testing.
The aim is to minimize the virus multiplication, ie to keep the virus in check so that it does not impair the function of the defense cells. Removing the HI virus completely from the body is currently not possible. Therefore, according to current knowledge, the therapy must be maintained for life.
Important is the regular and accurate intake of the tablets according to specification, otherwise the HIV resistant and thus the drugs can be ineffective. The start of therapy depends on the number of viruses and the CD4 helper cells in the blood.
Side effects of HIV therapy
Side effects of the combination therapy are varied and dependent on the active ingredient and the individual response of those affected. Often only temporary and easy to treat are diarrhea and headache. Especially in the first two weeks of therapy acute side effects are not uncommon.
The typical long-term consequences of HIV treatment include painful neuropathy of the arms and legs as well as disorders of fat metabolism and fat distribution. Subcutaneous fatty tissue forms on the face, arms and legs, while it increasingly accumulates on the abdomen and neck. In addition, it can also lead to organ damage, for example, the liver.
Other side effects of HIV therapy include:
- Nausea and constipation
- Metabolic disorders such as diabetes mellitus
- elevated blood lipid levels
- Renal impairment
In order not to jeopardize the efficacy of HIV therapy by stopping because of the various side effects, the doctor often has to change the combination of drugs.