Communicable Disease 1

• Microorganisms


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


  Microorganisms that can cause disease
• Communicable/infectious diseases


  Diseases that can spread from person to person and affect both animals and plants
• How pathogens spread from person to person

  1. Through the air (e.g. coughing, sneezing)

  2. Through contaminated food and water

  3. Through direct contact
• Pathogens spread through the air

  • Influenza virus
  • Measles virus
• Pathogens spread through contaminated food and water

  • Cholera (bacterial disease spread by contaminated water)
  • Salmonella (bacteria spread by contaminated food, particularly chicken)
• Pathogens spread through direct contact

  • Athlete's foot (fungal infection spread by walking barefoot on contaminated surfaces)
• Ways to reduce the spread of pathogens

  1. Being hygienic (e.g. washing hands, cleaning cooking items)

  2. Killing vectors (e.g. using insecticides to kill mosquitoes)

  3. Vaccinating people

  4. 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 if spread
• 1. Through the air - Diseases such as influenza and measles can spread via tiny droplets of saliva that we expel when we cough or sneeze.
• 1. Contaminated water - Diseases such as cholera can spread through water sources contaminated by the diarrhoea of infected people. 
• 1. Contaminated food - Diseases such as salmonella are spread by eating food which has been infected with salmonella, and then not cooked properly.
• 1. Direct contact - Athlete's foot is spread by walking barefoot on surfaces contaminated with the fungi. 
• Pathogens are microorganisms that cause infectious disease. These may be viruses, bacteria, protists or fungi. They may infect plants or animals and can be spread by direct contact, by water or by air.
• Bacteria and viruses may reproduce rapidly inside the body.
• Bacteria may produce poisons (toxins) that damage tissues and make us feel ill.
• Viruses live and reproduce inside cells, causing cell damage.