communicable diseases - general

• viruses:

  • very small
  • move into cells
  • make copies of themselves - cell bursts and releases new viruses that also move into cells
  • the damage and destruction of cells makes a person feel ill
• bacteria:

  • small
  • multiply very quickly - binary fission
  • produce toxins that can damage cells
• protists:

  • some are parasitic
  • use humans and animals as their hosts
• fungi:

  • either be single celled or have a body made of hyphae
  • can produce spores which can be spread to other organisms
• ways they are spread:

  • direct contact
  • water
  • airborne particles
• how damage can be reduced:

  • improving hygiene
  • reducing contact with infected individuals
  • removing vectors - use pesticides
  • vaccination