A general term for diseases produced by viruses.
About Viral Infections
In contrast to bacteria, viruses have no cells of their own. This means that they are also not living organisms in the stricter sense. They are instead made up of one or more molecules, inside of a protein shell. The genetic information found inside of this shell is needed for the viruses to reproduce. Many viruses are responsible for diseases.
Some are harmless and only trigger a minor cold, while others can cause serious diseases like AIDS. Other diseases caused by viruses include influenza, measles or inflammation of the liver (viral hepatitis).
Viruses invade healthy cells and start to multiply from these cells. Without these host cells, a virus cannot reproduce. Not all viruses cause symptoms and in many cases the body successfully fights back against the attackers.
This is the case with cold sores, which many people have experienced at some time. They are caused by viruses that are found in certain nerve cells and can lead to lip blisters in some people if the immune system is already occupied with other things.
It is relatively difficult to fight viruses with medication. To protect against some viruses the immune system can be “trained” by a vaccination so that the body is made less sensitive to the virus. Institute for Quality and Efficiency in Health Care (IQWiG)