Pathogens and Infections

Disease
1. Microorganisms that cause disease are called pathogens
2. Bacteria can reproduce rapidly inside the body. They may produce toxins that make us feel ill.
3. Viruses reproduce inside a body cell then destroy it when they burst out. The viruses then invade other cells.
4. An epidemic occurs when a wide spread of people have a disease. A Pandemic is when the disease affects a whole country or goes world wide.
5. In 1840's Semmelweis used evidence for the death rates of women to work out they were dying because doctors were transferring something to them from dead bodies. He made all the doctors wash their hands in chlorine water and, within a very short time, the death rate plummeted. We now know the infection that killed the women was caused by bacteria!
A New Hypothesis
1. Scientists are still learning about pathogens
  1. Doctors once thought that stomach ulcers were caused by stress or over-secretion of acid in the stomach. In 1982 researchers, Marshall and Warren, found bacteria in the stomachs of people with ulcers. The evidence to prove it came when Warren swallowed some of the bacteria and developed a stomach ulcer.

Resource summary

	Created by Imagine Dragons over 9 years ago