communicable disease

• Microorganisms


  A group of tiny organisms including bacteria, viruses, protists and fungi
• Pathogens


  Microorganisms that can cause disease
• Communicable/infectious diseases


  Diseases caused by pathogens that can spread from person to person
• Types of pathogens


  • Bacteria
  • Viruses
  • Protists
  • Fungi
• How pathogens spread


  1. Through the air

  2. Through contaminated food and water

  3. Through direct contact
• Pathogens spread through the air

  Carried in tiny droplets expelled when coughing or sneezing
• Pathogens spread through contaminated food and water


  Example: Cholera is spread by drinking contaminated water, Salmonella is spread by eating contaminated food
• Pathogens spread through direct contact

  Example: Athlete's foot is spread by walking barefoot on contaminated surfaces
• Methods to reduce pathogen spread

  • Being hygienic (washing hands, cleaning cooking items)
  • Killing vectors (using insecticides)
  • Vaccinating people
  • Quarantining infected people
• The best way to prevent a pathogen from spreading is to vaccinate everybody
• Quarantine is generally only used for really serious diseases that could harm others