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Viruses Flashcards

(60 cards)

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1
Q

recombination

A

exchange of genes between 2 chromosomes by crossing over within regions of significant base sequence homology

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2
Q

reassortment

A

when virsuses with segmented genomes (inflenza) exchange segments. high-frequency recombination. cause of worldwide influenza pandemics

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3
Q

complementation

A

when 1 of 2 viruses that infect the cell has a mutation that results in a nonfunctional protein. the nonmutated virus “complements” the mutated one by making a functional protein that serves both viruses

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4
Q

phenotypic mixing

A

occurs with simultaneous infection of a cell with 2 viruses. genome A can be partially or completely coated with surface proteins from B. therefore virus A can infect a new type of cell, although its progeny will not be able to

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5
Q

live attenuated vaccines

A
  • humoral and cell mediated immunity
  • boosters not needed
  • ex: smallpox, yellow fever, chicken pox, sabin polio virus, MMR, influenza (intranasal)
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6
Q

killed vaccines

A
  • produce only humoral immunity

- rabies, influenza, salk polio, and HAV

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7
Q

recombinant vaccines

A
  • HBV, HPV
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8
Q

DNA viral genomes

A
  • all dsDNA except parvoviridae

- all are linear except papilloma, polyoma and hepadnaviruses (circular)

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9
Q

RNA viral genomes

A

all are ssRNA excpet reoviridae
- positive stranded RNA viruses: I went to a retro(virus) toga(virus) party, where I drank flavored (flavivirus) corona(virus) and ate hippy (hepevirus) california (calicivirus) pickles (picornavirus)

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10
Q

which naked genomes are infectious?

A

dsDNA and + sense ssRNA (dsRNA and -ve sense ssRNA are not)

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11
Q

naked viruses

A

I gave PAPP smears and CPR to a naked Heppy

  • DNA: papilloma, adenovirus, parvovirus, polyomavirus
  • RNA: calicivirus, picornavirus, reovirus, hepevirus
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12
Q

theres something weird about all the “P” DNA viruses

A
  • pox - not icosahedral, replicates outside the nucleus
  • polyoma and papilloma - circular DNA
  • parvo - single stranded DNA
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13
Q

HSV-1

A

gingivostomatitis, keratoconjunctivitis, temporal lobe encephalitis, herpes labalis

  • latent infection in the trigeminal ganglia
  • transmitted via respiratory secretions, saliva
  • intranuclear inclusions seen on oral scrapings
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14
Q

HSV-2

A
  • herpes genitalis, neonatal herpes
  • latent in the sacral ganglia
  • transmitted by sexual contact, perinatally
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15
Q

VZV

A

HHV-3

  • chickenpox, shingles, encephalitis, pneumonia
  • latent in the dorsal root or trigeminal ganglia
  • most common complication of shingles is post-herpetic neuralgia
  • transmitted by respiratory secretions
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16
Q

EBV

A

HHV-4

  • mono (feer, HSmegaly, pharyngitis, lymphadenopathy - esp post cervical nodes)
  • transmitted via respiratory secretions and saliva
  • infects B cells by binding to CD21 on B cells and nasopharyngeal epithelial cells
  • atypical lymphocytes (abundant pale blue cytoplasm with basophilic rim) seen on PBS - reactive cytotoxic T cells
  • assoc with Hodgkin lymphoma, endemic burkitt lyphoma, nasopharyngeal carcinoma
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17
Q

CMV

A

HHV-5

  • congenital infection, mono with negative monospo, pneumonia, retinitis
  • “owl eye” inclusions
  • latent mononuclear cells
  • transmitted congenitally and via transfusion, sex, saliva, urine, transplant
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18
Q

HHV-6

A

roseola - high fevers for several days that can cause seizures, followed by diffuse maculopapular rash
- transmitted by saliva

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19
Q

HHV-8

A

Kaposi sarcoma, neoplasm of endothelial cells

  • seen in HIV/AIDS, transplants
  • dark/violaceous flat and nodular skin lesions representing endothelial growhts
  • can also affect GI tract and lungs
  • transmitted by sexual contact
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20
Q

HSV identification

A
  • viral culture for skin/genitalia
  • CSF PCR for encephalitis
  • Tzank smear - multinucleated giant cells
  • infected cells also have a intranuclear Cowdry A inclusions
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21
Q

Hepadnavirus

A

Hep B - not a retrovirus but has a reverse transcriptase

- enveloped, partially DS DNA and circular

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22
Q

Adenovirus

A
  • no envelope, DS and linear

- febrile pharyngitis, acute hemorrhagic cystitis, pneumonia, pink eye

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23
Q

parvovirus

A
  • ssDNA, not enveloped, linear
  • aplastic crises in sickle cell pts, 5th disease, hydrops fetalis, pure RBC aplasia/rhematoid arthritis-like disease in adults
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24
Q

papillomavirus

A
  • dsDNA, not enveloped, circular

- HPV warnts (1,2,6,11), CIN, cervical cancer (16, 18)

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25
polyomavirus
- dsDNA, not enveloped, circular - JC virus - PML - BK virus - transplant patients, affects the kidney
26
poxvirus
- dsDNA, enveloped, linear, replicates outside the nucleus, not icosahedral - smallpox, cowpox ("milkmaid blisters"), and molluscum contagiosum
27
reoviruses
- no envelope, dsRNA, icosahedral capsid - coltivirus - Colorado tick fever - rotavirus - #1 cause of fatal diarrhea in kids
28
picornaviruses
- no envelope, + ssRNA, icosahedral capsid - PERCH: poliovirus*, echovirus* (aseptic meningitis), rhinovirus, coxsackievirus* (aseptic meningitis, herpangina, HFM, myocarditis, pericarditis), HAV - 1 large polypeptide that is cleaved by proteases into functional viral proteins - * aseptic meningitis - are all enteroviruses (fecal-oral), except rhinovirus
29
hepevirus
- no envelope, + ssRNA, icosahedral capsid | - HEV
30
caliciviruses
- no envelope, + ssRNA, icosahedral capsid | - norovirus - viral gastroenteritis
31
flavivirus
- enveloped, + ssRNA, icosahedral capsid | - HCV, yellow fever, dengue, St. louis encephalitis, West Nile virus
32
togaviruses
- enveloped, + ssRNA, icosahedral | - rubella, eastern and western equine encephalitis
33
retroviruses
- enveloped, + ssRNA - HTLV - T cell leukemia (icosahedral) - HIV (complex and conical) - AIDS
34
coronaviruses
- enveloped, + ssRNA, helical capsid | - common cold and SARS
35
orthomyxoviruses
- enveloped, - ssRNA, helical capsid | - influenza
36
paramyxoviruses
- enveloped, - ssRNA, nonsegmented, helical capsid - PaRaMyxovirus - parainfluenza (croup), RSV (bronchiolitis) {{Rx - ribavarin}}, Measles, Mumps - all contain surface F (fusion) protein, which causes resp epi cells to fuse --> multinucleated cells - palivizumab prevents RSV pneumonia
37
Rhabdoviruses
- enveloped, -ssRNA, helical capsid | - rabies
38
filoviruses
- enveloped, - ssRNA, helical capsid | - ebola/marburg hemorrhagic fever - often fatal!
39
arenaviruses
- enveloped, -ssRNA circular (2 segments), helical capsid - LCMV - lymphocytic choriomeningitis virus - lassa fever encephalitis - spread by mice
40
bunyaviruses
- enveloped, -ssRNA circular (3 segments), helical capsid - california encephalitis, sandlfy/Rift valley fevers, crimean-congo hemorrhagic fever, hantavirus - hemorrhagic fever, pneumonia
41
delta virus
- enveloped, - ssRNA circular, uncertain capsid | - HDV - "defective" without HBV coinfection
42
segmented viruses
BOAR | - bunyavirus, orthomyxoviruses, arenaviruses, reoviruses
43
rhinovirus
- picornavirus, nonenveloped RNA virus - cause of the common cold - acid labile - destroyed in stomach, does not infect the GI tract like the enteroviruses
44
yellow fever virus
- flavivirus/arbovirus transmitted by Aedes mosquito - virus has monkey and human reservoir - high fever, black vomit, jaundice
45
rotavirus
- segmented RNA virus, the most important cause of infantile gastroenteritis - day care centers and kindergartens - villous destruction with atrophy leads to dec absorption of Na and loss of K
46
influenza viruses
- orthomyxoviruses, enveloped -ssRNA with 9 segment genome - contain hemagglutinin (promotes viral entry) and neuraminidase (promotes progeny release) - anti-hemagglutining IgA and IgG mediate immunity
47
genetic shift/antigenic shifts
causes pandemics - reassortment of viral genome, segments undergo high-freq recombination - ex: flu and swine flu recombination
48
genetic drigt
causes epidemics | - minor changes based on random mutation
49
rubella
- togavirus - fever, postauricular adenopathy, arthralgias, fine rash - blueberry muffin baby
50
measles virus
- paramyxovirus - Koplik spots and descending maculopapular rash - possible sequelae: SSPE, encephalitis, and giant cell pneumonia
51
mumps
- paramyxovirus - parotidis, orchitis, aseptic meningitis - may cause sterility
52
rabies virus
bullet shaped virus - Negri bodies commonly found in Purkinje cells (cerebellum, hippocampus) - travels to the CNS via retrograde motion - more commonly from bat, racoon and skunk in the US
53
HBV
DNA hepadnavirus - parenteral, sexual and maternal-fetal transmission - dsDNA --> + ssRNA --> dsDNA - incorporates into host genome - acute infection - "serum sickness": malaise, fever, skin rash, pruritis, lymphadenopathy, joint pain
54
HCV
DNA flavivirus | - has no 3'-5' proofreading, so many errors are made during replication and many subspecies can coexist in one person)
55
HDV
RNA delta virus - parenteral, sexual and MFM transmission - dependent on HBV
56
HEVv
- RNA hepevirus - fecal-oral - high mort in preggos
57
HBsAg
- noninfective envelope glyoprotein --> spheres/tubules 22nm in diameter - indicative of active Hep B infection
58
3 structural genes of HIV
- env (gp120 for attachment and gp41 for fusion/entry) - gag - capsid protein - pol - reverse trascriptase
59
HIV diagnosis
ELISA is sensitive, Western Blot is specific | - AIDS if < 200 CD4, AIDS-defining condition or CD % < 14%
60
prion diseases
- conversion of a normal (usually alpha helical) protein to a B-pleated form, cannot be degraded by proteases - sporadic (CJD), inherited (Gerstmann-Staussler-Scheinker) or acquired (kuru)
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