Pathogens and disease

• Communicable diseases are caused by pathogens
• Pathogens are microorganisms which can cause infectious diseases
• Pathogens depend on the host to provide the suitable conditions and nutrients that they need to grow and reproduce
• 4 types of pathogen:

  • bacteria
  • viruses
  • fungi
  • protists
• Bacteria:

  • single celled living organisms
  • very small (1-2 micrometres)
  • bacteria can make us ill by producing toxins
• Three bacterial shapes:

  • bacillus (rods)
  • coccus (spheres)
  • spirillum (spirals)