Infection and response

• Pathogens are microorganisms that cause infectious disease
• Bacteria and viruses may reproduce rapidly inside the body. Bacteria may produce poisons (toxins) that make us feel ill. Viruses live and reproduce inside cells, causing damage.
• WHITE BLOOD CELLS

  1. Produce antitoxins
  2. Produce antibodies
  3. Injest pathogens (Phagocytosis)
• Vaccines are weakened or inactive form of a pathogen
• Vaccines stimulate the white blood cells to produce antibodies that destroy the pathogen. This makes the person immune to future infections by the microorganism, because the body can respond by rapidly making the correct antibody, in the same way as if the person had previously had the disease
• The MMR vaccine is used to protect children against measles, mumps and rubella
• Antibiotics, such as penicillin, are medicines that help to cure bacterial disease by killing infective bacteria inside the body
• The use of antibiotics has greatly reduced deaths from infectious bacterial diseases
• Antibiotics cannot kill viral pathogens
• Antibiotics kill individual pathogens of the non-resistant strain but individual resistant pathogens survive and reproduce, so the population of the resistant strain rises. Antibiotics and vaccinations may no longer be effective causing it to spread rapidly
• It is difficult to develop drugs that kill viruses without also damaging the body’s tissues
• Overuse and inappropriate use of antibiotics has increased the rate of development of antibiotic-resistant strains of bacteria (like MRSA)
• The development of antibiotic-resistant strains of bacteria necessitates the development of new antibiotics
• Toxins are proteins