viral microbiology

  1. What is a virus?
    A virus is a program that self-replicates• It is not data
  2. RNA Bacteriophages
    the maturation protein (present in the mature virus particle as asingle copy)• coat protein• lysis protein (involved in the lysis process that results in release ofmature virus particles)• a subunit of RNA replicase, the enzyme that brings aboutreplication of the viral RNA
  3. The single-strandedDNA genome of theThe bar represents 100 nm.Micrographs were taken with aPhilips EM 300 electronmicroscope operated at 60 kV.virus φX174 is sosmall that____are required toencode all its essential proteins. This virusprovided the first example of overlapping genes
    overlapping genes
  4. Entrance into the cell is accompanied by theconversion of this single-stranded DNA into adouble-stranded molecule called the
    replicative form (RF).
  5. Some single-stranded DNA viruses, such asM13, have
    filamentous virions
  6. Single-stranded DNA Bacteriophages These viruses are very useful tools for
    DNA sequencing andgenetic engineering. They are released withoutactually killing the host.
  7. What are vaccines?
    • A vaccine is a substance that stimulates the
    • body’s immune response.
    • • The goal of vaccination is to prevent or control
    • an infection.
  8. Negative-Strand RNA Viruses:
    Rabies, Influenza, and Related Viruses
  9. Bird Flu
    • Avian Influenza viruses occur naturally in wild
    • birds
    • • wild birds carry influenza viruses in their
    • i t ti
    • Bird Flu
    • intestines but virus usually does not make
    • wild birds sick)
    • • highly contagious among birds and can make
    • domesticated birds (chickens, ducks, turkey)
    • sick; can be fatal
  10. Bird Flu in Humans
    • transmission from birds to humans is possible,
    • but is not sustained
    • • virus obtained from direct or close contact with
    • infected poultry or surfaces (secretions and/or
    • excretions)
    • • can also be transmitted through an intermediate
    • host (ex. pig
  11. humans can be infected with influenza
    types A, B, and C viruses
  12. influenza A
    • is classified into subtypes according
    • to surface glycoproteins hemagglutinin (HA)
    • and neuraminidase (NA)
  13. Low and High Pathogenic Viruses
    • viruses classified based on its capability of
    • causing a disease
  14. Low Pathogenic Avian Influenza (LPAI)
    • associated with mild disease in poultry; such as
    • ruffled feathers and drop in egg production
  15. High Pathogenic Avian Influenza (HPAI)
    • leads to severe illness and mortality in poultry; H5N1
    • is a highly pathogenic virus
  16. Hepatitis A
    • RNA virus;
    • • transmitted enterically;
    • • infect the liver;
    • • clinically not distinguishable;
    • • incubation period 15 to 50 days (A) and
    • 22 to 60 days (E);
    • • symptoms: jaundice, anorexia, vomiting,
    • malaise;
    • • food-associated outbreaks of hepatitis A
    • recorded in great numbers: in 1988, raw
    • clams were the source of nearly 300,000
    • cases of hepatitis A in China;
    • hepatitis A is relatively resistant to heat,
    • drying, low pH, and γ-irradiation.
  17. Norwalk-Like Viruses
    Small, round structural viruses (SRSVs), 28-38 nm in size.
  18. Norwalk-Like Viruses
    • Symptoms: nausea, vomiting, diarrhea, and
    • other symptoms common to gastroentiritis.

    • Pathogenesis: the viruses infect and kill cells
    • of the small intestinal mucosa
  19. Varicella zoster virus (VZV)
    • •VZV: Chickenpox
    • •VZV: Shingles
    • •Re-activation of latent infection
    • •Suppression of cell mediated immunity
  20. HIV is a Retrovirus which means
    • It contains a single-stranded RNA genome
    • – The HIV will incorporate it’s own genome into
    • it’s host cell and hijack the normal functions of
    • the cell to replicate itself
    • – This process will eventually lead to cell
    • destruction
  21. The target for HIV is
    • the CD-4+ Helper TCells,
    • which are the backbone of the
    • immune system.
  22. HIV-1 GroupsGroup M (“majority
    cause of the global HIV-1epidemic; many strains
  23. Group N (“non-O/non-M”) & Group O
    (“outlier”):HIV-1 Groups
    limted to Western African nations
  24. HIV-1 GroupsGroup M (“majority
    • HIV-2 is largely restricted to West
    • Africa. This suggests that HIV-2 may less efficiently
    • transmitted than HIV-1
  25. HIV TransmissionHIV enters the bloodstream through:
    • – Open Cuts
    • – Breaks in the skin
    • – Mucous membranes
    • – Direct injection
  26. HIV TransmissionCommon fluids that are a means of
    • Blood
    • – Semen
    • – Vaginal Secretions
    • – Breast Milk
  27. White Blood Cells
    Types of WBCs
    • Neutrophils
    • – Eosinophils
    • – Basophiles
    • – Monocytes
    • – Helper T cells
    • – Cytotoxic T cells
    • – Memory T cells
    • – Suppressor T cells
Card Set
viral microbiology