Pathogens

• Pathogens are microorganisms that cause infectious diseases.
• Bacteria:

  Once inside the human body, bacteria reproduce very rapidly.

  Bacteria can then release harmful chemicals called toxins.
• Toxins damage tissues and make us feel ill.
• Viruses cannot reproduce by themselves. They can only reproduce inside a host cell.
• Viruses:

  1. The virus invades the host cell
  2. The virus now reproduces inside the host cell
  3. This is very damaging to the cell. When the virus leaves the cell, it can cause the cell to burst open and die.
• Some pathogens are spread in the air e.g. in water droplets (influenza)
• Some pathogens can be spread directly in water (e.g. cholera)
• Some pathogens are spread by direct contact between individuals (e.g. HIV)
• Reducing the spread of pathogens:

  • washing you hands before eating
  • providing people with clean drinking water
  • using condom during sexual intercourse reduced the spread of HIV
  • In the case of some highly infectious diseases such as Ebola, patients may be isolated
  • vaccinations