Micro 2 Test 3

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bbeckers88
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117554
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Micro 2 Test 3
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2011-11-17 16:33:15
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micro 2 test 3
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  1. what were the first viral diseases investigated and by who?
    • rabies- pasture
    • yellow fever- Reed
  2. what are viruses?
    • non-living intracellular parasites
    • small
  3. how can you grow viruses?
    in tissue cultures (mainly use bird eggs)
  4. what is a virion
    a single viral particle
  5. what is the viral genome made of?
    either RNA or DNA
  6. what is a nucleocapsid
    the nucleic acid surrounded by a capsid (protein coat)
  7. what is an envelope?
    • a lipoprotein coat stolen from the host
    • has glycoprotein spikes for host interaction
  8. what does it mean if a virus is naked??
    it has a capsid but no envelope
  9. what symmetry can a capsid have?
    helical or icosahedral
  10. prions
    • no nucleic acid
    • self replicating protein
    • possibly related to viruses
    • causes spongiform encephalopathies
  11. what are the spongiform encephalopathies?
    • mad-cow
    • creutzfeldt-jacobs
    • kuru
    • scrapie
  12. what are the steps of bacteriophage replication
    • 1. Adsorption
    • 2. penetration
    • 3. prefabrication
    • 4. maturation
    • 5. viral release
  13. describe bacteriophage adsorption
    • adsorbs to receptor site with tail fibers
    • (receptor sites are lipopolysaccharide, pili, and flagella)
    • beginning of latent period
  14. describe bacteriophage penetration
    • tail penetrates bacteria, releases nucleic acids, takes over host
    • beginning of eclipse period
  15. describe bacteriophage prefabrication
    • viral genome replicated
    • viral mRNA synthesized
    • all viral parts are prefabricated
  16. describe bacteriophage maturation
    • end of eclipse phase
    • virus assembled (dont grow!!)
  17. describe bacteriohpage viral release
    • end of latent period
    • viruses produce lysosome, rupture cell wall, and released
  18. what are the steps of animal virus replication
    • 1. adsorption
    • 2. penetration and uncoating
    • 3. synthesis of DNA/RNA viruses
    • 4. maturation
    • 5. viral release
  19. describe animal virus adsorption
    • naked virus- capsid binds to host cell receptors
    • enveloped virus- glycoprotein spikes bind to host cell receptors
  20. describe animal virus penetration and uncoating
    • naked- change in capsid structure on adsprtion to plasma membrane, release nucleic acids into cytoplasm
    • enveloped
    • a. envelope fuses with cytoplasmic membrane and releases nucleocapsid into cytoplasm
    • b. endobytosed into cell (endocytic vesicle), lysosomes fuse to vesicle, release nucleic acids
  21. describe the synthesis of DNA animal viruses
    • early synthesis- viral DNA synthesized-> transcription to RNA-> inhibits host (usually occurs in host nucleus, except for pox virus)
    • often remain latent
    • early viral genes- DNA binding proteins and enzymes
    • late viral genes- structural genes
  22. what are the 4 groups of RNA viruses
    • (+) stranded
    • double stranded (ds)
    • (-) stranded
    • retrovirus
  23. describe synthesis of (+) stranded RNA viruses
    • (+) strand used as giant mRNA
    • translated into viral enzymes by host
    • RNA polymerase forms (-) strand RNA
    • (-) strand forms more (+) strands used as mRNA and for new viruses
  24. describe synthesis of ds RNA viruses
    • transcriptase copies (-) strand of genome to mRNA
    • mRNA translated into enzymes to synthesize new viruses
  25. describe synthesis of (-) stranded RNA viruses
    • viral transcriptase converts (-) strand to (+) strand
    • (+) strand acts as mRNA
    • viral replicase produces double stranded RNA that assembles new virus
  26. describe synthesis of retrovirus
    • has single stranded (+) RNA genome
    • synthesize mRNA and replicate RNA by converting RNA-> DNA by reverse transcriptase
    • (-) DNA copied to create double stranded proviral DNA
    • proviral DNA synthesizes (+) RNA for new viruses
  27. describe maturation of animal viruses
    • capsid formation
    • 1. synthesis directed by late genes
    • 2. spontaneously self assembled around nucleic acid
    • 3. location of maturation is viral specific
    • if enveloped...
    • 1. late viral mRNA transcribes glycoproteins-> inserted into host cell membrane
    • 2. viral particle enveloped during exocytosis
  28. describe viral release of animal viruses
    • naked- infected cell lysed, virons released
    • enveloped- possible lysis, otherwise budding from membrane bound organelles then exocytosed
  29. what are the effects of viral infection
    • persistance
    • transformation
    • immunological escape
  30. what is persistance
    virus is not cleared from host followign primary infection, remains associated with specific cells
  31. what is transformation
    establish persistanct infections that stimulate uncontrolled cell growth causing transformation or immortalization of cells (CANCER)
  32. what is immunological escape
    virus can evade detection (herpes)
  33. what are the DNA viruses
    • Poxvirus
    • herpes virus
    • adenovirus
    • Papovaviridae
    • parvovirus
  34. what does the poxvirus cause
    • mulluscum contagiosum
    • small pox
    • cow pox
    • monkey pox
    • orf
  35. describe the pox virus
    • big, brick shaped
    • 1 molecule of linear double stranded DNA
  36. describe molluscum contagiosum
    • pearly/flesh colored bumps
    • contagious
    • not harmful
    • impaired immune system= disfiguring
  37. describe smallpox
    • caused by variola virus (major= more severe)
    • highly contagious via respiratory secretions and direct contact
    • causes fever, chills, nausea, severe muscle aches, rash
    • rash: flat-> papules-> postules->scar
    • vaccination= 1967
    • last case in somalia in 1977
    • erradicated in 1980
  38. describe cow pox
    • zoonosis
    • infected teats of milking cows
    • treated with vaccinea virus (no one knows what it is!!)
  39. describe monkey pox
    • rare
    • rain forest in west africa
    • initially found in lab monkeys
  40. orf
    viral pox from sheep and goats
  41. what is important about the herpes virus
    a leading cause of human viral disease, second to influenza. once infected, you are infected for life!
  42. describe the herpes virus
    • icosahedral symmetry
    • enveloped
    • single molecule of ds DNA
    • attracted to neurons
  43. which diseases are caused by the herpes virus
    • cytomegalovirus
    • varicella-zoster virus
    • herpes simplex virus
    • epstein barr virus
    • human herpes virus 6,7, and 8
  44. describe cytomegalovirus
    • in US 15% of college age and 50% of 35 y.o. are infected
    • spread in body secretions (sexually)
    • transplacental- spreads to fetus (1 in 40)
    • most common viral cause of congenital mental retardation
    • no symptoms in children, maybe mild in adults
    • problematic in immunocomprimised adults (CMV-retinitis in 15% of AIDS)
  45. what is caused by varicella-zoster virus
    • chicken pox
    • shingles
  46. describe chicken pox
    • respiratory droplet/direct contact transmission
    • rate of infection >90%
    • spreads from lungs by entering blood (viremia)-> sub-endothelial-> endothelial
    • forms papules-> fluid filled vesicles-> postules->scab
    • vesicles are found on the scalp
    • itchy, can cause bacterial superinfection
    • recovery in 2 weeks
    • problems in utero if infection during 1st trimester
  47. describe shingels
    • reoccurence of latent varicella infection
    • virus from nerves to epidermis
    • reactivated by stress, injury, disease
    • severe radicular pain in infected nerves
    • chicken pox-like lesions in dermatomal pattern
  48. diagnosis of varicella-zoster virus
    • culture from lesions
    • giant cells with inclusions
  49. treatment of varicella-zoster virus
    • live attenuated vaccine leads to antibodies and cell mediated immunity
    • chemotherapy- various nucleotide analogs
  50. descripe herpes simplex virus
    • 1st infect mucoepithelial or enter thru wounds-> latnent infection in neuronal cells
    • HSV-1 usually above the waist
    • HSV-2 usually below the waist
  51. diseased causd by HSV-1
    • herpes labialis: fever blisters/ cold sores
    • eczema herpeticum: widespread cutaneous HSV if have pre-existing eczema
    • keratoconjunctivitis: infection of cornea. leading cause of corneal blindness in industrealized countries
  52. diseases from HSV-2
    • Genital herpes
    • herpetic whitlow: on fingers or hands
    • herpetic grandiatorum: skin lesions mainly on wrestlers from direct contact
  53. describe genital herpes
    • prodome (pre infection) 1-2 days of buring sensation
    • primary infection: viremia, fever, swollen lymph nodes, pain on urination
    • secondary episodes: caused by reactivation of virus, less severe and shorter
    • triggers: fever, menstration, stress, UV light
    • person is infectous even when not in active rash
  54. treatment of herpes simplex virus
    • paitent counseling
    • drugs (Acyclovir)
    • nucleotide analog, inhibits DNA polymersae
    • no action on latent infection
    • doesnt reduece symptoms
    • oral and topical
  55. what does the epstein barr virus cause
    • infectous mononucleosis
    • african-burkitts lymphoma
    • nasopharyngeal cancer
    • hairy oral leukoplakia
  56. describe infectious mononucleosis
    • occurs worldwide in humans, usually in childhood
    • aquired thru contact with cervical or oral secretions
    • multiplies B cells in oralpharyngeal epithelium
    • asymptomatic in children
    • T cell # increases to 80% of WBCs causing enlarged liver, spleen, and lymph nodes
    • activation of T cells limits proliferation of B cells
    • lasts 8-10 days
  57. describe african-burkitts lymphoma
    • tumor in jaw and face in children
    • tumor shows EBV DNA and tumor antigens
    • patients have an increased level of anti-EBV antibodies
  58. describe nasopharyngeal cancer
    • epithelial tumor
    • tumor contains EBV-DNA
    • possible genetic predisposition or environmental factors
  59. describe hairy oral leukoplakia
    • EBV associated
    • lesions in the mouth
    • opportunistic infection in HIV patients
  60. diagnosis of EBV
    • elecated white count
    • downy cells
  61. HHV-6
    • causes roseola infantum
    • -sudden rash, 3 day fever, rose rash, 6th disease
  62. HHV-7
    causes no known disease
  63. HHV-8
    • found in saliva of AIDS patients
    • associated with karposis sarcoma
    • colorful blotches, usually painless
  64. describe the adenovirus
    • no envelope
    • ds DNA
    • icosahedral caapside with 12 penton fibers to bind to host
    • attacks mucoepithelial cells of conjunctiva, respiratory tract, GI and gastrourinary tracts
  65. what does the adenovirus cause
    • acute respiratory infection- common cold
    • pharyngitis- like strep
    • gastroenteritis
    • epidemic keratoconjunctivitis
  66. what does Papovaviridae cause
    • HPV
    • polymvirus
  67. descrive HPV
    • wart causing virus
    • naked double stranded DNA
    • icosahedral cpsid
    • replicate in suamous epithelium of skin and mucous membranes
    • different serotypes determins warts
  68. what types of warts are caused by HPV
    • common warts
    • plantar warts- painful, deep, bottom of feet
    • laryngeal papillomas- benign epithelial warts
    • genital warts- common STI. 30 different types. many people are asymptomatic. associated with penile, uterine, and cervical cancers
  69. describe polymavirus
    • naked ds DNA
    • icosahedral symmetry
    • history unknown, no syndromes
  70. parvovirus
    • smallest naked, icosahedral DNA
    • very resistant
    • infects dogs, cats, mice, and humans
  71. describe the human parvovirus
    • B19 found in respiratory secretions
    • Fifth disease
    • -1st stage: fever/cold symptoms 8 days after infection
    • -2nd stage: slapped cheek rash on face- erythema infectiosum. resolves in 1-2 weeks
  72. what are the RNA viruses
    • paramyxovirus
    • Togaviridae
  73. descrive paramyxovirus
    • enveloped
    • (-) stranded RNA
    • helical symmetry
    • causes: Rubeola (measles) mumps, parainfluenza
  74. describe the rubeola virus
    • attaches via hemmagglutinin
    • lacks neuraminidase activity
    • caused by inhilation of respiratory secretions
    • symptomatic
    • highly contagious, especially 2-3 days before rash
  75. describe rubeola (measles) uncomplicated
    • fever, runny nose, cough, conjunctivitis, Koplik's spots on mucosal membranes (white with blue halo)
    • maculopapular rash from face to extremities
  76. describe rubeola (measles) with complications
    • impaired cell mediated immune response (giant cell pneumonea)
    • otitis media and bacterial pneumonia
    • encephalitis
    • sum-acute sclerosing pan encephalitis (1-10 years after infection, progressing, very rare)
  77. control of measles
    • life long immunity
    • MMR attenuated live virus
  78. describe parainfluenza
    • there are 4 types
    • infect the upper and lower respiratory tracts
    • causes 40-50% of croup cases
  79. describe mumps
    • parotid gland swelling
    • transmitted via respiratory secretions and saliva
    • highly contagious
    • infects respiratory tract-> lymphoid tissue-> viremia
  80. complications of mumps:
    • orchitis
    • aseptic meningitis
  81. control of mumps
    • MMR vaccine
    • single serotype, life long immunity
  82. describe the togaviridae virus
    • (+) strand RNA
    • enveloped
    • icosahedral symmetry
    • member of rubrivirus genus
  83. togaviridae causes
    german measles (rubella)
  84. describe the german measles
    • respiratory secretions
    • upper respiratory tract infection-> lymph-> viremia-> elsewhere
    • possible rash after 2 week inhibation period
  85. congenital German measles infection
    • highest risk in early pregnancy
    • infects placenta-> fetus
    • neonate defects: hearing loss, mental retardation, congenital heart defects, neurologic problems, opthalmic problems, infectous of 1 year!

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