3. TOPICS TO COVER
• CLASSIFICATION
• REPLICATION
• DIAGNOSTICS
• PUBLIC HEALTH VIRUSES
• EMERGING & RE-EMERGING VIRUSES
Thursday, January 19, 2012
4. PLENARY REPORTS
• CLASS MUST HAVE 6 GROUPS
(7-8 PEOPLE EACH GROUP)
• A TOPIC WILL BE ASSIGNED &
TO BE REPORTED FORMALLY
IN CLASS
• FOCUS: ADVANCES IN
DIAGNOSTICS
• 3 GROUPS PER MEETING
(MARCH 9 & 16)
Thursday, January 19, 2012
6. VIROLOGY
INTRODUCTION
Thursday, January 19, 2012
7. INTRODUCTION
• VIROLOGY
• scientific study of viruses and
the disease they cause
• VIRUSES
• an infective agent typically
consists of nucleic acid in a
protein coat
• too small to be seen by light
microscopy
• multiply within living cells of
host (obligate parasite)
• filterable
Parungao-Balolong 2011-2012
Thursday, January 19, 2012
8. VIRUSES
• Contain DNA or RNA
• Contain a protein coat (capsid)
• Some are enclosed by an envelope
• Some viruses have spikes
• Most viruses infect only specific
types of cells
in one host
• Host range is determined by
specific host attachment sites and
cellular factors
Parungao-Balolong 2011
Thursday, January 19, 2012
9. VIRUSES
Parungao-Balolong 2011
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10. RELATIVE SIZES &
TOOLS
Jane Flint Principles of Virology, 2004
Parungao-Balolong 2011-2012
Thursday, January 19, 2012
11. ARE THEY ALIVE?
• Viruses challenge the way
we define LIFE:
• they do not respire
• they do not display
irritability
• they do not move
• they do not “grow”
• WHAT THEY DO: they
reproduce and adapt to
new hosts
Parungao-Balolong 2011-2012
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12. STRATEGIES
FOR SURVIVAL
• Genomes are packaged
inside a particle
(transmission)
• Genome contains all
information needed for
infection cycle
(attachment to release)
• Establishment in a host
population
Parungao-Balolong 2011-2012
Thursday, January 19, 2012
13. NATURE OF VIRUSES
• Viruses are Small Particles
Parungao-Balolong 2011-2012
Thursday, January 19, 2012
14. NATURE OF VIRUSES
• Viruses Have Genes • virus code efficiently
• virus use host cell • multifunctional
proteins
Parungao-Balolong 2011-2012
Thursday, January 19, 2012
15. NATURE OF VIRUSES
• Viruses are Parasites
Parungao-Balolong 2011-2012
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16. DOWN MEMORY LANE...
• Dmitri Iosifovich
Ivanowsky (1892)
• Martinus Beijerink (1898)
• Filterable agent: Tobacco
Mosaic Virus
Parungao-Balolong 2011-2012
Thursday, January 19, 2012
18. THE THIRD PARTY..
• Walter Reed (1899)
• Yellow fever:
transmission by insect
vectors
Parungao-Balolong 2011-2012
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19. LINKS TO CANCER???
• VIRUSES AND
ONCOGENESIS
• Ellerman and Bang
(1908)
• Chicken leukemia
• Peyton Rous (1911)
• Rous Sarcoma
virus Parungao-Balolong 2011-2012
Thursday, January 19, 2012
20. AND THEN, THERE WERE THE
PHAGES
• Bacteriophages Era
• Frederick Twort
(1915)
• discovery of phages
• Felix D’ Herelle
(1917)
• role in immunity
Parungao-Balolong 2011-2012
Thursday, January 19, 2012
21. AND THE REST IS
HISTORY
• Wendell Stanley (1935): crystallization of TMV
• Delbruck (1940s): modern molecular biology and
virology
• Lwoff (1949): discovery of lysogeny
• Enders et al., (1949): poliovirus and tissue culture/
plaque assays
• 1980s: Immunology and PCR technology was
Parungao-Balolong 2011-2012
Thursday, January 19, 2012
22. WHY DO WE STUDY
VIROLOGY?
• Some Viruses Cause Disease
Rabies
Common
Cold
Smallpox
HIV
Parungao-Balolong 2011-2012
Thursday, January 19, 2012
23. WHY DO WE STUDY
VIROLOGY?
• Some Viruses Cause Disease
Pepper Mottle Cauliflower Mosaic Rice Tungro
Virus Virus Virus
Papaya Ringspot Virus
Tobacco Mosaic Virus Parungao-Balolong 2011-2012
Thursday, January 19, 2012
24. WHY DO WE STUDY
VIROLOGY?
• Some Viruses Cause Disease
Foot & Mouth Porcine Reproductive & Respiratory
Classical Swine Fever
Disease Syndrome (PRRS)
Ebola
Avian Flu Parungao-Balolong 2011-2012
Thursday, January 19, 2012
25. WHY DO WE STUDY
VIROLOGY?
• Some Viruses Cause Disease
AH1N1
Parungao-Balolong 2011-2012
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26. WHY DO WE STUDY
VIROLOGY?
• Some Viruses are Useful
• Phage Typing of Bacteria
• e.g. Salmonella spp.
• classified into strains on the
basis of the spectrum of
phages to which they are
susceptible
• advantage: Epidemiology
Parungao-Balolong 2011-2012
Thursday, January 19, 2012
27. WHY DO WE STUDY
VIROLOGY?
• Some Viruses are Useful
• Sources of Enzymes
• RNA polymerase (T7 phage)
• Genetic Pesticides
• gene from baculovirus against
worms
Parungao-Balolong 2011-2012
Thursday, January 19, 2012
28. WHY DO WE STUDY
VIROLOGY?
• Some Viruses are Useful
• Gene Vector for Protein Production
• baculovirus, adenovirus
• vaccine component
• Gene Vector for Treatment of
Genetic Diseases
• retrovirus
• immunodeficient cases
Parungao-Balolong 2011-2012
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29. WHY DO WE STUDY
VIROLOGY?
• Virus Studies Have Contributed to Knowledge
• Hershey and Chase experiment (T2 phage)
Parungao-Balolong 2011-2012
Thursday, January 19, 2012
30. WHY DO WE STUDY
VIROLOGY?
• Virus Studies Have Contributed to Knowledge
• Characterization of enhancers (genes of Simian SV 40)
• Characterization of transcription factors and localization of
protein signal (genes of Simian SV 40)
Parungao-Balolong 2011-2012
Thursday, January 19, 2012
31. WHY DO WE STUDY
VIROLOGY?
• Virus Studies Have Contributed to Knowledge
• Discovery of introns (adenovirus)
• Role of cap structure at 5’ end of eukaryotic mRNA
(vaccinia and reovirus)
• discovery of internal ribosomal entry site (RNA of
poliovirus)
• discovery of RNA pseudoknot (turnip yellow mosaic
virus)
Parungao-Balolong 2011-2012
Thursday, January 19, 2012
32. NEXT MEETING
STRUCTURE, CLASSIFICATION & REPLICATION
Thursday, January 19, 2012
