What are infections?
An infection occurs when a germ enters the body and multiplies there. There are many different pathogens; the most common are viruses and bacteria. But not every pathogen automatically causes illness. The decisive factor is how aggressive the germ is and how well our immune system can defend itself against it. At birth, the immune system is not yet fully developed. It must first become acquainted with the many different infectious agents in order to form defense mechanisms against them. This is
one reason why children are usually ill more often than adults.
In some cases, the immune system does not always develop properly. In the case of an allergy, the immune system may turn against actually harmless substances such as pollen, cat hair or peanuts as it confuses these with harmful pathogens. Or the immune system turns against healthy cells of the own body, for example with a form of diabetes mellitus. Some of these diseases only occur in adulthood and can become a chronic disease. This means that the disease lasts for a long time or even for a lifetime.