12.7 Preventing and treating disease

• active immunity - exposure to a pathogen triggers antibody production

  including natural and artificial
• passive immunity - a person is given antibodies rather than producing

  including natural and artificial
• natural active immunity:

  • regular immune response to presence of a pathogen
  • produces antibodies in response to a pathogen
• natural passive immunity:

  • new born babies do not have a fully developed immune system
  • acquire immunities from mother
  • antibodies from the mother in milk called colostrum containing high anti-bodies
• artificial passive immunity:

  • involves taking antibodies produced by one organism and injecting them into the bloodstream of another
  • short lasting immunity
• examples of artificial passive immunity:

  • tetanus - found in contaminated soil and animal faeces, injection of anti-bodies from horses. Causes muscle spasm unable to swallow.
  • rabies - progressive and fatal inflammation of brain and spinal cord. Viral disease. Antibodies given before. 100% fatal. Bitten by a rabid dog
• artificial active immunity:

  e.g vaccination - stimulated to produce anti-bodies by an immune response by injecting 'safe' pathogens
• types of antigens used in vaccines:

  • killed/inactivated bacteria & viruses e.g whooping cough
  • attenuated strains e.g polio
  • toxin molecules that have been altered a and detoxified e.g flu
  • genetically engineered antigens e/g covid 19
• what are the signs that the non-specific immune system is working?

  • coughing
  • sneezing
  • fever
  • Inflammation
• what is adaptive immunity?

  second line of defence

  specific immune response - B cells & T cells
• live attenuated vaccine - made of pathogen itself but a much weaker and tamer version
• inactivated vaccine - pathogen has been killed
• epidemic - when a communicable disease spread throughout national level
• pandemic - when a communicable disease spread throughout international level
• heard/mass vaccination - vaccinating a large proportion of the population to reduce spread
• no vaccination:

  • malaria
  • HIV
• antibiotics - used to fight infection by killing bacteria and stopping growth
• antibiotic resistance:

  • bacteria not killed by antibiotic enables them to reproduce and survive
  • therefore, allele for antibiotic resistance is passed onto their offspring
  • for example MRSA and C.difficle
• prevention of antibiotic resistance:

  • antibiotics should only be prescribed when needed
  • patients should finish the complete course of antibiotics
  • introduction of infection control in hospitals
• bactericidal antibiotics - kill bacteria by destroying cell wall causing bursting
• bacteriostatic antibiotics - inhibits growth of bacteria by stopping protein synthesis and production of nucleic acid so bacteria can't grow or divide