Terminology - General infection theory

Terminology - General infection theory
Pathogens play a role in health care that can be transferred from person to person.



The 'microbes' of Louis Pasteur are better known to us as micro-organisms. When they come into contact with a person or a surface, they speak of infection or contamination. For this the word infection is also used, but it has a double meaning in our use of language. It is good to elaborate on the confusion regarding the meaning of the concept of infection.

  • The original and correct meaning of the word infection is contamination or contamination: coming into contact with something.
  • In the second sense, an infection refers to an inflammation or illness that has arisen after (pathogenic) micro-organisms have come into contact with the body.


There is only an infection in the sense of inflammation or disease when all three conditions are met.

  1. The microorganisms have invaded the body of the host.
  2. They can maintain themselves there.
  3. They can multiply in the host's body.


When correctly using the words it can therefore be stated that an inflammation or disease is always preceded by an infection in the sense of contamination or contamination. After all, inflammation can not occur without contamination. Certain diseases are contagious. The characteristic of these so-called infectious diseases is that they are caused by the transmission of living (or viable) pathogenic micro-organisms, also called pathogens or pathogens. These pathogens can be transmitted via direct or indirect contact. This transfer can take place from person to person, as is the case with a cold virus or the Mycobacterium tuberculosis that causes TB. The transfer from animal to human is sometimes also possible. Examples include certain types of the avian influenza virus and the MERS virus, which is responsible for the development of the Middle East respiratory syndrome through contact with camels.


Pathogens play a role in health care that can be transferred from person to person. Apart from a contagious infection, other factors also play a role in the occurrence or not of an inflammation or disease.On an individual and per situation they can ensure that the infected body of the host can or can not successfully defend against the invasion of microorganisms.



These other factors are:

  • The attack power of the micro-organism (virulence);
  • The location of the infection on or in the body (porte d'entrée);
  • The number of germs that have been transmitted;
  • The physical condition and quality of the host's immune system.


The body of an infected person can react to the infection by developing a local defense process (local inflammatory reaction) or by an inflammation reaction (disease) spread throughout the body, for example by raising the body temperature. Fortunately, these immune reactions are almost always effective and the infected person will heal. After experiencing a viral disease, as an extra long-term defense system in the body, a recognition mechanism has normally been formed for this specific pathogen. With a subsequent contact, the defense can be brought to full strength within a very short time, so that no more disease can occur. This phenomenon is called immunity. Unfortunately, no memory system in the human body has developed for a bacterial infection. Fortunately, external auxiliaries can be deployed in the form of antibiotics, when the body can no longer handle the battle alone. However, this only applies as long as no resistance has been developed by this bacterium for the administered antibiotics.


In more and more cases, resistance appears to be an unexpected factor in the control of serious or increasingly 'everyday' inflammations such as bladder inflammation. The disease process can then continue indefinitely, with an increasingly fatal outcome. As a matter of fact, mankind is back in the battle against ever more infectious diseases because of the ever increasing number of resistant bacteria. The era in which medicine could offer healing in (almost) all bacterial infectious diseases is already behind us, it seems. Innocent infections nowadays seem to be just as life-threatening as in the past when there were no antibiotics yet.


In almost all cases the result of a successful immune response, with or without outside help, is that the body is ultimately completely free of the pathogenic micro-organism. In some cases, a small amount of microorganisms can remain in the host without having symptoms of the disease. We then speak of carrier status and the person in question is a carrier. Depending on the number of pathogens circulating in the blood (so-called viral load), a carrier is or is not contagious to his environment.