1. Infectious Diseases Unit
Copyright © 2010 Ryan P. Murphy

2. "The first chapter of The Hot Zone is one of the most horrifying things I've read in my whole life--and then it gets worse. That's what I keep marveling over: it keeps getting worse. What a remarkable piece of work." Stephen King
Copyright © 2010 Ryan P. Murphy

3. Ebola virus

9. Infectious Diseases will include
Viruses
Bacteria
Parasites
Copyright © 2010 Ryan P. Murphy

10. Black Plague (also called Bubonic Plague) In four years, a bacterium killed 20 to 30 million Europeans.
Copyright © 2010 Ryan P. Murphy

11. In the Extreme East, China dwindled from 123 million inhabitants at the beginning of the 13th century to just 65 million during the 14th century, because of the plague.
You do the math…
Copyright © 2010 Ryan P. Murphy

12. In the Extreme East, China dwindled from 123 million inhabitants at the beginning of the 13th century to just 65 million during the 14th century, because of the plague.
You do the math…
58 Million Dead
Copyright © 2010 Ryan P. Murphy

13. Copyright © 2010 Ryan P. Murphy

14. Spanish Flu –WWI (virus) (40 Million Dead Worldwide) Pandemic
-Note: The Spanish Flu is not as well known as it occurred during war time and countries kept death toll a secret.
Copyright © 2010 Ryan P. Murphy

16. Since 1914 to 1977 Smallpox (Bacterium)
Killed 300 to 500 million people.

17. Since 1914 to 1977 Smallpox
Killed 300 to 500 million people.

20. The smallpox virus.
Copyright © 2010 Ryan P. Murphy

21. Polio (Virus)– Killed and Crippled Millions until about 1958

22. Another great vaccine saved millions from Polio in 1955.

23. HIV (Virus) – 60 Million Currently Infected

24. Malaria (Plasmodium Parasite) is found in 500 million people
Malaria (Plasmodium Parasite) is found in 500 million people million cases are very severe.
Hundreds of million die. Most of which are children.
Copyright © 2010 Ryan P. Murphy

25. Gonorrhea and syphilis (Bacterium)
62 million people worldwide are affected.
Most are 15 to 29 years of age.
Copyright © 2010 Ryan P. Murphy

26. Pneumonia (Bacteria): It kills 3.5 million people each year.

27. 2 million people die annually of tuberculosis.
About 150 million people are estimated to have died of TBC since 1914.

28. Mad Cow Disease

29. Mad Cow Disease
Prions (virus like protein – smaller than virus)

31. Viruses infect just about every type of life form.

32. How do they spread? How fast can they spread?
Usually through fluid exchange
Blood
Saliva
Mucus
Wastes
LET’S EXHANGE FLUIDS!!!

33. Section 18.1 Summary – pages 475-483
Viral Structure
A virus has an inner core of nucleic acid, either RNA or DNA, and an outer protein coat called a capsid.
Capsid
Some relatively large viruses have an envelope, surrounding their capsids.
Envelopes are made from the same type of materials of the cell membrane.
Nucleic
acid
Envelope
Section 18.1 Summary – pages

34. Lipid Envelope
Nucleic Acid
Protein
Capsid
Virion Associated Polymerase
Spike Projections

35. Varies in size, shape and symmetry Highly impo. for classification
3 types of capsid symmetry:
Cubic (icosahedral)
Helical
Complex
5 basic types of virus structure:

36. Viruses are non-living because…
Viruses are not made of cells.
They have no cell parts.
They do not grow and develop.
They do not respond to their
environment
Copyright © 2010 Ryan P. Murphy

37. Viruses COULD be considered living because…
Viruses do Replicate, but only by invading living cells, not by themselves.
They do Evolve / Mutate.
This is why we still do not have a cure for HIV/AIDS
End notes for hour 1
Copyright © 2010 Ryan P. Murphy

38. How do viruses multiply / infect?
Two ways
Lytic Infection – a virus enters a cell, makes copies of itself, and causes the cell to burst.
Lysogenic Infection – host cell makes copies of virus indefinitely because the virus DNA is imbedded in the host DNA sequence

39. 1 5 4 2 3 7 6 8 Virus attachment and entry Uncoating of virion
Migration of genome 1
nucleic acid to nucleus 5
Transcription
Genome replication
Translation of virus mRNAs 4 2 3 7
Virion assembly
Release of new virus
particles 6 8

40. Section 18.1 Summary – pages 475-483
Lytic cycle
Bacteriophage
Bacterial DNA
Nucleic
acid
Bacterial
host cell
B. Entry
A. Attachment
The bacteriophage
injects its nucleic acid
into the bacterial cell.
E. Lysis and Release
The host cell breaks open and
releases new virus particles.
C. Replication
D. Assembly
The host’s metabolic
machinery makes viral
nucleic acid and proteins.
New virus particles
are assembled.
Section 18.1 Summary – pages

42. Section 18.1 Summary – pages 475-483
Viral Replication
Before a virus can replicate, it must enter a host cell.
A virus recognizes and attaches to a host cell when one of its proteins interlocks with a molecular shape that is the receptor site on the host cell’s plasma membrane.
In some viruses, the attachment protein is in the capsid or in the envelope.
In the T4 bacteriophage, a protein in the tail fibers recognizes and attaches the T4 to its bacterial host cell.
Section 18.1 Summary – pages

43. Section 18.1 Summary – pages 475-483
T4 Bacteriophage
Capsid
Nucleic
acid
Tail
Tail fiber
Section 18.1 Summary – pages

44. A bacteriophage is any one of a number of viruses that infect bacteria
Inject genetic material, which they carry enclosed in an outer protein capsid

46. Q: If you get a cold sore do you have herpes?
A: Yes, Herpes Simplex, Not genital Herpes called Herpes Complex.

47. URGENT! Coldsores are a strain of herpes simplex.
The herpes STD is a different strain of herpes called herpes complex.
Copyright © 2010 Ryan P. Murphy

48. Herpes simplex can infect other areas besides your mouth.
Copyright © 2010 Ryan P. Murphy

49. “Let’s be friends forever.”
Lysogenic Virus – A virus that can hide inside your cells DNA until it breaks out (lytic) and then hides again.
With you forever.
“Let’s be friends forever.”
Copyright © 2010 Ryan P. Murphy

50. Section 18.1 Summary – pages 475-483
Lysogenic cycle
B. Provirus Formation
A. Attachment and Entry
Provirus
Although
the provirus
is inactive,
it replicates
along with
the host cell’s
chromosome.
C. Cell Division
Bacterial host
chromosome
A lysogenic virus
injects its nucleic
acid into a bacterium.
The viral nucleic acid is called
a provirus when it becomes
part of the host’s chromosome.
LYSOGENIC CYCLE
LYTIC CYCLE
The provirus leaves
the chromosome.
The cell breaks
open releasing
viruses.
Viral nucleic acid and
proteins are made.
Section 18.1 Summary – pages

51. The virus waits for many months, even years until conditions are right.
Stress.
Sun burn.
Dryness.
Then it strikes and looks for new host.
Copyright © 2010 Ryan P. Murphy

52. She will now have his herpes virus in her cells for the rest of her life.
Her cells will continue to copy the virus as they reproduce. Until…
Copyright © 2010 Ryan P. Murphy

53. She will now have his herpes virus in her cells for the rest of her life.
Her cells will continue to copy the virus as they reproduce. Until…
Lytic outbreak
Copyright © 2010 Ryan P. Murphy

54. Other Types of Viruses
Oncogenic viruses: carry genes that disrupt the normal cell cycle of animals, which can lead to cancer (HPV virus)
Retroviruses: viruses that contain RNA as their genetic material
(HIV, influenza)
Prions: “protein infectious particles;” abnormally shaped proteins located in the brains of animals
(Mad cow disease, CWD)

56. Prevention & Treatment
Vaccinations - made from dead or inactive viruses.
Inactivated - do not replicate in the host
Attenuated - viruses that have been genetically altered so they are not capable of causing the disease.
Boosters - an additional dose of a vaccine to extend protection.
Poliovirus

57. Symptoms
Amount of virus
Time
Virus

58. Human T-cell Leukaemia Virus (HTLV-1) Hepatitis C virus
Epstein Barr Virus
Burkitt’s Lymphoma
Human papillomavirus
Benign warts
Cervical Carcinoma
Human T-cell Leukaemia Virus (HTLV-1)
Leukaemia
Hepatitis C virus
Liver carcinoma

59. Prevention & Treatment
Anti-viral drugs - drugs that interfere with the viral nucleic acid synthesis. These are given to infected patients.
Best way to control disease is through prevention.
ANTIBIOTICS are NOT useful against viruses.
Photo Courtesy of CDC3

60. Where is the Centers for Disease Control and Prevention located?
Atlanta, Georgia
Moscow, Russia

61. World Health Organization
AKA – W.H.O.
Decided in 1967 to eradicate small pox the disease from the general population.
This was officially accomplished in 1980, with the last known case in Somalia, 1977.

62. Emerging Viruses
These are newly discovered viruses that are emerging in different parts of the world.
They exist is isolated habitats and infect humans when those habitats are developed.
Some examples include: Ebola, HIV, and West Nile.

63. Treatment of Viral Diseases
Antibiotics do not work on viruses!!
Why?
Antibiotics destroy the cell walls of bacteria, but viruses are not composed of cells
White blood cells