Virus!

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Virus!

• Not Alive,
• But Still Deadly

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Bacteriophages or Virus?
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Bacteriophages or Virus?

• Bacteriophages attack bacteria (prokaryotes)
• viruses attack eukaryotic cells (animal and plant
  cells).
• Viruses and bacteriophages take over cells and
  use the host cell's organelles to make more of
  their own parts.

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Virus Versus Cell
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Viral Size and Structure
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Viral Size and Structure

• Virus shape is determined by the DNA/RNA and
  protein coat covering its genome (DNA/RNA)
• Basic structure
• Capsid Protein coat
• Nucleic acid core RNA or DNA
• Genome can be single or double stranded
• Helps determine shape of virus
• Lipoprotein coat
• Envelopes (covers) capsid in some viruses

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Virus Categories (Examples of Viruses)
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Virus Categories

• DNA viruses stable, do not mutate rapidly
• Single-stranded or double-stranded
• Includes Smallpox and Hepatitis B
• RNA viruses mutate rapidly, unstable
• Single-stranded or double-stranded
• Includes HIV and Rhinovirus

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Lytic and Lysogenic Cycles
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The Lytic Cycle

• Virus attaches to host cells membrane and
  injects its nucleic acid into the host cell.
• The viral nucleic acid takes over protein
  synthesis, creating new viruses.
• The host cell bursts, lyses, releasing the newly
  formed viruses.

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The Lysogenic Cycle

• Nucleic acid of virus becomes part of the host
  cells chromosome
• Nucleic acid remains in the cell in this form for
  many generations

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AIDS
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HIV and AIDS

• HIV is a retrovirus that leads to AIDS
• The virus kills or damages cells of the body's
  immune system, progressively destroying the
  body's ability to fight infections
• 25 million people worldwide have died from AIDS
• A combination of at least three drugs is
  recommended to suppress the virus from
  replicating and boost the immune system
• There is no cure for HIV and AIDS

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Chickenpox
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Chickenpox

• Caused by the varicella-zoster virus (VZV) and
  common in children under 12
• Highly contagious, itch rash
• Children can be vaccinated against the disease
• Some children may still get chickenpox though
• Those that have had chickenpox have a natural
  immunity to the disease
• VZV can lie dormant within the body and cause
  shingles later in life

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Influenza
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Influenza

• Two common types Influenza A and Influenza B
• Flu Symptoms include
• fever (usually high), headache, extreme
  tiredness, dry cough, sore throat, runny/stuffy
  nose, muscle aches
• Nausea, vomiting, and diarrhea can occur but are
  more common in children
• 5 to 20 of U.S. residents will get influenza
  each year
• 36000 people on average die from
  influenza-related causes
• 200,000 will admitted to the hospital as a
  result of influenza-related causes.

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Smallpox and Vaccination
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Smallpox and Vaccination

• Edward Jenner is credited with the first
  vaccination against smallpox
• Country-lore suggested that people who caught
  cowpox from their cows did not get smallpox
• Jenner transferred material from the pocks of a
  dairymaid to James Phipps, the 8 year old son of
  his gardener
• James became mildly ill from cowpow
• Weeks later, Jenner infected James with smallpox
• No infection now or during future trials
• The first vaccination published was a success!