How infectious diseases work

Infectious diseases is always something transferred to the affected.  Contagions don’t arise spontaneously when people do certain things.  Instead they have to be conveyed from someone already infected.  They can also be transferred from animals.  Many contagious diseases have arisen through close contact with domesticated animals.  Or they have been transferred through unhygienic butchering of wild animals.  HIV arose in this way when the incompetent have butchered monkeys and gotten raw monkey blood into themselves.  This virus causes aids which did not exist before the 20th century.

Something people might not think of in this context are parasites.  They may be arthropods, flatworms, roundworms or spiny-headed worms.  There are parasites which are single-celled eukaryotes too.  No-one of them can be killed by use of antibiotics.  In contrast there can be other medications attacking specific parasites.  Bacteria are the only ones antibiotics work on.  Not even then it is certain it always work.  Over the course of time they have evolved resistance against certain specific types of common antibiotics.  Which makes them less and less efficient.

I don’t consider viruses living since they lack metabolism.  They consist of a casing of protein containing RNA and in some cases DNA.  This casing opens in contact with certain living cells.  Its content is the injected and can be copied by the cell.  Which in turn makes it possible for entire viruses to be copied.  This process can overload cells and cause infectious diseases.

Some denies that diseases are caused by external contagions.  Those can’t have any ideas of science being something done together.  The scientific community does not only apply to knowledge of the past.  There is a collective effort for everything science is handling.  Diseases’ different causes is one of these subjects.  For sure there was a small number of pioneers.  However, the science of the area is independent on their authority.  On the contrary the number of individuals themselves examining this thing have since then increased exponentially.  I think it is today a matter of more than a hundred thousand people.  Would all those conspire to deliberately make people ill?  To me this is patently absurd.

Loads of specific contagions has been linked to specific diseases.  Naturally this have gone wrong sometimes.  Both influenza and malaria were first thought to be caused by bacteria.  Now we know influenza is caused by a virus.  Malaria is due to a parasite which is a single-celled eukaryote.  But these two were demonstrated by people within the scientific community.  It was not about individuals denying that bacteria matters at all.  In the light of accumulated knowledge such denial appear thoughtless.

There are individuals claiming the relationship is the opposite.  That bacteria and viruses would be produced by our bodies when ill.  Does one have basic knowledge of cells one realises it is impossible.  Bacterial and eukaryotic cells differs fundamentally.  It is like claiming that certain conditions result in spontaneous shapeshifting.  Viruses are not cells in themselves.  However, their genes can be compared and in this way build family trees.  Such correlate with time and place for people’s contact with the disease.  In contrast they don’t correlate with how human are related.

Different contagions have historically been found in different parts of the world.  Peoples living there for millennia have evolved some resistance against these very diseases.  Everyone from there don’t have it although many have.  People from other parts of the world rarely have such resistance.  This is way so many Europeans died from infections in the tropics.  Moreover, they oftentimes did not know which habits suited the climate.  Hence the myth of “unhealthy climates”.

 

Uploaded on the 8th of August 2025.