Pathogens and disease

 Infectious diseases are caused by Micro-organisms.

Micro-organisms that cause infectious disese are called Pathogens

BACTERIA

Bacteria are:

smaller than plant or animal cells.

single celled living organisms

mostly harmless (pathogenic bacteria are the minority)

VIRUSES

Viruses are :

smaller that bacteria

usually a regular shape

able to cause disease in any organism (bacteria, plant , human)

HOW PATHOGENS CAUSE DISEASE

Bacteria and viruses reproducing rapidly is what makes you ill

Bacteria reproduce by binary fission AKA splitting in two.  They often produce toxins as well as directly damaging your cells

Viruses reproduce by taking over your cells. They rarely produce toxins but they do damage and destroy your cells.

Its this damage and the introduction of toxins into your body that causes you to have a high fever and get a rashes or headaches.

IGNAZ SEMMELWEIS (mid 18-50's)

He realised that 'childbed fever…