Bacteria and viruses: similarities and differences

The most important things in brief

• Since the outbreak of the pandemic, we have reacted very sensitively when we felt weak or sick.
• Is it perhaps another infection with SARS-CoV-2? Many people ask themselves that.
• But whether spring, summer, autumn or winter: viruses are always on the move, and not just corona viruses.
• Not only viruses but also bacteria can make us ill.

Anthropologists and evolutionary theorists have recently re-dated the age of homo sapiens based on recent discoveries. According to this, our first ancestors lived in today's Maghreb around 300,000 years ago. That is remarkable - and yet infinitesimally small compared to how long bacteria and viruses have been at home on our planet. Research puts it at 3.6 billion years, which means these tiny pathogens have lived on Earth about 12 times longer than we have.

Are bacteria and viruses living things?

It is difficult to say whether people in northern Africa were also suffering from colds or flu at the time. However, it is not entirely unlikely if you consider that there are probably around 300 cold viruses. It is also possible that some of these viruses are much older and have already caused colds, coughs and malaise in prehistoric human species.

3.6 billion years is a period that covers 80 percent of the time since the earth formed 4.5 billion years ago - why don't viruses evolve? They do this by mutating; This can be clearly observed with the corona viruses. That being said, viruses have found a niche, they don't even need to evolve into more complex forms to survive. This does not mean, however, that they are living beings; unlike bacteria, viruses have no metabolism and no cell wall.

How viruses and bacteria make us sick

Viruses are not considered to be living beings in their own right, but bacteria are - albeit as the simplest form of life. There is also an enormous difference in their size, because while a virus is only about 20 to 300 nanometers long (that is 0.00002 to 0.0003 millimeters or 0.02 to 0.3 micrometers) and can only be seen under the electron microscope a bacterium grows to a full micrometer, i.e. to a thousandth of a millimetre.

While bacteria, once they have entered our body, multiply by cell division and spread throughout our organism, viruses reprogram our body's cells or destroy them. More often than not, however, the reprogrammed cells are tasked with reproducing the virus, leading to disease. In the case of bacterial infestation, on the other hand, the metabolism of the invaders usually makes us ill.

How do we get infected by viruses or bacteria?

The transmission paths of pathogens have not only been a much-discussed topic since Corona. In principle, the germs are everywhere, on door handles, on smartphones, on public transport - and at some point they get on our hands and in our organism. It often helps to disinfect your hands regularly. But they also penetrate through the air, namely through droplets containing pathogens, which our sick counterpart throws away when coughing, sneezing or speaking and which make their way through the air into our mucous membranes.

Bacteria and viruses are also able to penetrate the human organism via the blood or other bodily fluids. If food or water is contaminated and we eat from it, we can also become infected. And last but not least, mosquitoes are often carriers of pathogens, there are a few examples of this, such as malaria.

Prevention is only possible against viruses

The big question has long been how best to prevent these pathogens. The dividing line between viruses and bacteria is relatively clear. Viral diseases can be prevented with vaccinations, such as the winter flu or Covid-19. It must be said that a vaccination does not necessarily prevent an illness, but at least ensures a milder course and, as with Covid, a significant decrease in mortality.

Anyone who is infected by viruses without being vaccinated can sometimes use antivirals. These are drugs that can inhibit viral replication. In the case of bacterial infestation, however, antibiotics are a good remedy. These are drugs that target the invaders and kill them. However, preventive measures such as vaccinations do not help with bacterial diseases.