B1: 1.4 - Pathogens & Disease

Infectious diseases are found all over the world. They are caused by a microorganism entering and attacking your body.
1. Microorganisms which cause disease are called pathogens.
Bacteria are single-celled organisms that are much smaller then animal and plant cells. Although some bacteria can cause disease, others can be harmless, or even useful.
1. Viruses are even smaller, they have regular shape and cause disease in every living organism.
Once bacteria and viruses are in your body they reproduce rapidly.
1. Bacteria split in two and often produce toxins. Sometimes they directly damage your cells.
2. Viruses take over the cells of your body, damaging and destroying them. They very rarely produce toxins.
Semmelweis discovered that his students were carrying diseases on the hands from dead bodies to patients, so he made them start washing their hands before delivering children.
1. Immediately less mothers died, yet since no one had ever seen bacteria or viruses doctors didn't accept his ideas for many reasons e.g religious.

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	Created by cole060100 over 9 years ago