Definition
The human immunodeficiency virus (HIV) can be transmitted through blood, through sexual intercourse or from mother to child. Acute HIV infection leads to flu-like symptoms. In the further course the immune system is destroyed and opportunistic illness can occur.
These diseases are infections that have no effect on healthy people. Today, the virus can be well controlled by antiviral therapy. Although the disease is not yet curable, patients can lead a symptom-free life. The prognosis has improved significantly in recent years.
The Epidemiology
Despite a decline in the rate of newly infected persons (Roman Koch Institute, 2011), HIV and AIDS remains a major topic in the population. In Germany, about 70,000 people are currently infected, about two thirds of whom are male. A higher number of unreported cases can be assumed.
More than 30 million people worldwide are affected, and about three million die every year as a result of the infection. Although a large proportion of these – around 20 million – are concentrated on the African continent, AIDS is still an important topic in Western Europe, also in terms of numbers. The number of newly infected people here reached its peak in the early 1980s, when nobody knew about the virus and its transmission.
Nevertheless, the rate of infected persons in the population (prevalence) continues to increase, which is also due to the better and longer survival of patients. There is a correlation between risk of the disease and membership of certain groups. The prevalence of the disease among homosexual men is still particularly high.
Other risk groups include users of i.v. drugs, people from countries where a large proportion of the population is affected, and patients who need frequent transfusions, for example because of hemophilia. The latter is hardly a risk at present, as blood donations are examined and selected accordingly in this country.
The HI-Virus
The human immunodeficiency virus (HI virus) is a retrovirus – the virus consists of RNA strands and must first transcribe its RNA into DNA during replication. This knowledge is used for therapeutic purposes. Replication can be inhibited by various drugs and the progression of the disease can be prevented.
There are two known subtypes of the HI virus. Man and some species of monkeys are the reservoir of the virus. They attack the immune system and lead to a weakening of the immune system.
As a result, opportunistic infections can occur – this form of infection runs without symptoms in healthy people because their immune system can fight the respective pathogens. In immunocompromised persons, however, reactivation of herpes viruses, pneumonia and numerous other diseases can occur. These are subtypes of the HI virus.
Both subtypes can lead to immunodeficiency in the case of an infection and trigger AIDS in advanced stages. The HI-Virus 1 triggers the infection in most cases and is spread all over the world. The HI-Virus 2 is mainly restricted to the African continent and accounts for only a small percentage of HIV infections.
