Virus and Bacteria

Virus and bacteria can make us sick or ill

Bacteria and virus can provoke illness. But what are these guys and why are some of them good guys and some of them bad guys for us?

Bacteria and virus are so very tiny, that you cannot see them with your naked eye. Bacteria are a sort of micro ”insects” and virus are a sort of micro-micro ”insects”. You need 1.000 bacteria holding hands to reach from one end of an ordinary ant to the other. And you need 1.000 virus to reach from one end of a bacteria to the other end.

Bacteria are all over. You can find them in the river, in the water down the earth, inside the earth itself, inside all plants and animals and on and inside all human beings. Most bacteria are not harmful to us.  Some bacteria we even cannot live without, because they assist in the stomach and the intestines to dissolve the food we eat into tiny, tiny parts. If the bacteria are inside our stomach and intestines all of them are good to us, because they make sure, that there is no space for harmful bacteria. Even bacteria living on our skin are good for us, because they prevent harmful bacteria to settle down.

Virus are harmful micro-micro “insects”, that enter and exploit plants, bacteria, animals and human beings, because that’s the only way they can multiply.

If you want to repeat facts about bacteria and virus, watch this video:

Cold, Flu, Tuberculosis and Diarrhea

These are the ways we can catch a cold, get the flu, get tuberculosis and get diarrhea. Watch closely these videos:



  • The food we eat and the water we drink might contain virus or harmful bacteria from the soil or from animal or human stools. In this way virus and harmful bacteria get directly into our stomach and intestines
  • When we get a scratch from a piece of wood or a rusty nail, harmful bacteria are transferred into our blood
  • While giving birth the mother loses blood and at the same time she is at risk for getting harmful bacteria into her blood veins
  • We can get a bite from a mosquito by which a stream of bacteria is sent into our blood veins. The mosquito had the bacteria from another human being or an animal
  • When we get close to someone who is sick and coughs and sneezes, tiny drops that contain virus or harmful bacteria may enter our mouth, nose or eyes
  • When we shake hands with someone, who has caught a cold and has virus and harmful bacteria on his hand, we may get sick if later we rub our eyes or put a finger into our mouth

What happens in a sick body

What happens in your body, when you get sick? 

When virus or harmful bacteria get into your body, they are immediately attacked by the body. White blood cells and lymph are directed to the virus and bacteria to destroy them. You can watch the attack, when the intrusion takes place in a scratch of your skin. It´s called inflammation and it is good for you, it repairs your skin.

No matter which parts of your body the virus and harmful bacteria have entered, the white blood cells will penetrate the walls of the blood veins find them and try to destroy them. Take a look below at how the immune system works.

How the immune system works

How the immune system works
Throughout our body we have a network of lymphatic vessels, like we have blood veins. The network contains a liquid called lymph. The lymph helps the white blood cells kill the virus and harmful bacteria.

If the white blood cells and the lymph don´t immediately succeed in killing the virus and harmful bacteria, we get sick.

But our body has one more weapon for the fight: It can turn up the temperature of our body; we get a fever. This means we get a temperature above 38° C and our skin will be chilly and pale or quite the opposite, burning hot and we sweat. We can also get the chills, we can feel sick and we can have a head ache.

Bacteria and virus don´t like the fever, but the fever makes the white blood cells and the lymph work faster.

If our temperature exceeds 40° C our skin will be red.

If our temperature exceeds 42,6° C we can die, because the high temperature destroys important substances throughout our body.


If your body is healthy and strong it will normally kill most of the virus and harmful bacteria, that enters your body. White blood cells and lymph do most of the job, but fever can assist as well