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Remember :. A pathogen is a micro-organism that has the potential to cause disease. An infection is the invasion and multiplication of pathogenic microbes in an individual or population. Disease is when the infection causes damage to the individual’s vital functions or systems.
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Remember: • A pathogen is a micro-organism that has the potential to cause disease. • An infection is the invasion and multiplication of pathogenic microbes in an individual or population. • Disease is when the infection causes damage to the individual’s vital functions or systems. • An infection does not always result in disease!
To make us ill microbes must: • reach their target site in the body • attach to the target site they are trying to infect • multiply rapidly • obtain their nutrients from the host • avoid and survive attack by the immune system
Infection enters through: • Natural openings in your body • Eyes – hand to eye in tear duct to mucus • Mouth – attaches to teeth swallow kills most • Nose – infect mucus membranes • Directly infect your skin • Take advantage of breaks in skin • Bug bites • Animal bites • Penetrate skin
Infection enters through: • Natural openings in your body • Directly infect your skin • Bacteria - Staphylococci, coryneforms • Fungi - athlete’s foot, ringworm • Viruses - wart viruses live in dead skin cells • Take advantage of breaks in skin • Bug bites • Animal bites • Penetrate skin
Infection enters through: • Natural openings in your body • Take advantage of breaks in skin • Cuts • Catheters • Burns • Bug bites • Animal bites • Penetrate skin
Infection enters through: • Natural openings in your body • Directly infect your skin: • Take advantage of breaks in skin • Bug bites • Bacteria • Parasites • Viruses • Animal bites • Penetrate skin
Infection enters through: • Natural openings in your body • Directly infect your skin: • Take advantage of breaks in skin • Bug bites • Animal bites • Rabies • Penetrate skin
Infection enters through: • Natural openings in your body • Directly infect your skin: • Take advantage of breaks in skin • Bug bites • Animal bites • Penetrate skin • Swimmers itch – larval worms in water • Hook worm – larval worms in soil
Reproduction • Bacteria – divide
Reproduction • Virus - uses host Aids virus budding from a white blood cell.
The Defenders • First line of defence • Skin • Muscus membranes • Second line of defence • Third line of defence
The Defenders • First line of defence • Second line of defence • White blood cells • Third line of defence
The Defenders • First line of defence • Second line of defence • Third line of defence • Immune response, antibody creates antigens which engulf and digest the invader