Pathogens

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Pathogens You
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• A pathogen is any disease causing agent
• Bacteria
• Viruses

What is a pathogen?
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• Prokaryote
• No nucleus
• Circular DNA
• Kingdom Eubacteria
• 3 Basic shapes
• Bacilli
• Cocci
• Spirilla
• Streptococci Chain
• Staphylococci - Clumps

What is bacteria?
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• Exotoxins
• Poison made of protein released by the cell
• Tetanus
• Endotoxins
• Poison made of lipids and carbs released when the
  bacterial cell dies
• E.coli

How does bacteria cause disease?
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• Antibiotics
• Drugs that interfere with bacterial cellular
  functions
• Penicillin stops cell wall synthesis
• Tetracycline stops protein synthesis
• Antibiotic Resistance
• Bacteria is becoming harder to fight!
• Natural Selection

What is the treatment for a bacterial infection?
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• Physical Characteristics
• Genetic Material
• DNA
• RNA
• Protein Coat
• Capsid
• Envelope (some)
• Infect ALL living things
• Animals
• Plants
• Bacteria (Bacteriophage)

What is a virus?
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• No! Viruses do not share many of the
  characteristics of living organisms.
• Can replicate only inside a living cell, the host
  cell.

Are viruses living things?
HIV Virus
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• The Lytic Cycle
• A virus attaches to the host cell.
• The virus must insert its genetic material into
  the host cell.
• The viral genetic material takes control of the
  host cell and uses it to replicate parts
  assemble viruses.
• The newly formed viruses are released from the
  host cell (lysis).

How do viruses infect their hosts?
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The Lytic Cycle
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• The Lysogenic Cycle
• Same as lytic BUT
• Viral genetic material goes DORMANT once inserted
  in the host
• Needs a trigger to return to lytic cycle
• Lysogenic stage HIV
• Lytic stage - AIDS

How do viruses infect their hosts?
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How are viruses transmitted?

• Viruses are transmitted through vectors, such as
• Airborne
• Influenza (Deadliest!)
• Common cold

• Contaminated food or water
• Hepatitis

• Infected animal bite
• West Nile
• Rabies
• Avian influenza (bird flu)
• Ebola

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How are viruses transmitted?

• Viruses are transmitted through vectors, such as
• Sexual contact
• HIV
• Herpes

• Contaminated blood products or needles
• HIV
• Hepatitis

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• Viruses cannot be treated with antibiotics!
• You generally have to wait for the virus to run
  its course and let your immune system fight it
  off, or.
• Be Pro-active!
• Vaccine harmless version of virus causes
  immunity to future exposure

How are viruses treated?