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Flashcards in Viruses Deck (60):
1

recombination

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

2

reassortment

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

3

complementation

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

4

phenotypic mixing

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

5

live attenuated vaccines

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

6

killed vaccines

- produce only humoral immunity
- rabies, influenza, salk polio, and HAV

7

recombinant vaccines

- HBV, HPV

8

DNA viral genomes

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

9

RNA viral genomes

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)

10

which naked genomes are infectious?

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

11

naked viruses

I gave PAPP smears and CPR to a naked Heppy
- DNA: papilloma, adenovirus, parvovirus, polyomavirus
- RNA: calicivirus, picornavirus, reovirus, hepevirus

12

theres something weird about all the "P" DNA viruses

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

13

HSV-1

gingivostomatitis, keratoconjunctivitis, temporal lobe encephalitis, herpes labalis
- latent infection in the trigeminal ganglia
- transmitted via respiratory secretions, saliva
- intranuclear inclusions seen on oral scrapings

14

HSV-2

-herpes genitalis, neonatal herpes
- latent in the sacral ganglia
- transmitted by sexual contact, perinatally

15

VZV

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

16

EBV

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

17

CMV

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

18

HHV-6

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

19

HHV-8

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

20

HSV identification

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

21

Hepadnavirus

Hep B - not a retrovirus but has a reverse transcriptase
- enveloped, partially DS DNA and circular

22

Adenovirus

- no envelope, DS and linear
- febrile pharyngitis, acute hemorrhagic cystitis, pneumonia, pink eye

23

parvovirus

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

24

papillomavirus

- dsDNA, not enveloped, circular
- HPV warnts (1,2,6,11), CIN, cervical cancer (16, 18)

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)