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Step 1 > microbio virology > Flashcards

microbio virology Flashcards

1
Q

Recombination

A

exchange of genes between 2 chromosomes by crossing over

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2
Q

Reassortment

A

when viruses with segmented genomes exchange genetic material; can happen with genes from different kind of virus (human, swine, and avian viruses)

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3
Q

complementation

A

when 1 of 2 viruses that infects a cell has a non-functioning protein but the other virus provides it. for example, Hep D requires the presence of replicatinghep B virus to supply HBsAg, the envelope protein for HDV

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4
Q

phenotypic mixing

A

simultaneous infection of a cell with two viruses; genome of virus A can be coated with the surface proteins of virus B; the type B virus coat determines the tropism of the hybrid virus, but the progeny from the infecton ave a type A coat that is encoded by type A genetic material

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5
Q

live attenuated vaccines

A

induce humoral and cell-mediated immunity; examples are small pox, yellow fever, rotavirus, chickenpox (VZV), Sabin polio virus, MMR, influenza (intranasal); dangerous for immunocompromised people; no booster needed for live atenuated vaccines

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6
Q

killed/inactivated vaccine

A

induce only humoral immunity; rabies, influenza (injected), Salk polio, and hep A vaccines

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7
Q

Subunit vaccines

A

Hep B virus; HPV (types 16, 18, 6, and 11)

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8
Q

Naked viral genome infectivity

A

purified nucleic acids of most dsDNA and the POS strand of ssRNA (=mRNA) viruses are infectious; Naked nucleic acids of the NEG strand ssRNA and dsRNA viruses are not infectious. They require polymerases contained in the complete virion

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9
Q

where do DNA viruses replicate?

A

the nucleus (except poxvirus_

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10
Q

where do RNA viruses replicate?

A

cytoplasm (except influenza and retroviruses)

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11
Q

Naked (nonenveloped viruses)

A

pappilomavirus, adenoviru, parvovirus, polyomavirus, calicivirus, picornavirus, reovirus, and hepevirus

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12
Q

Generally (though there are exceptions), DNA viruese

A

are ds, linear, icosohedral, and replicate in the nucleus

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13
Q

Herpes viruses

A

ds, linear, enveloped; include HSV-1, HSV-2, VZV, EBV, CMV, HHV-6/HHV-7, HHV-8

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14
Q

HSV-1

A

oral (and sometimes genital) lesions; spontaneous temporal lobe encephalitis; keratoconjunctivitis

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15
Q

HSV-2

A

genital (and some oral) lesions

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16
Q

VZV (aka HHV-3)

A

chickenpox, zoster (shingles)

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17
Q

EBV (aka HHV-4)

A

mono, Burkitt-Lymphoma, Hodgkin lymphoma, nasopharyngeal carcinoma

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18
Q

CMV (aka HHV-5)

A

AIDS retinitis; also consider in transplant recipients; congenital defects

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19
Q

HHV-6

A

roseola (exanthum subitum)

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20
Q

HHV-7

A

less common cause of roseola

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21
Q

HHV-8

A

Kaposi sarcoma

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22
Q

Hepadenavirus

A

enveloped, partially DS, and circular; example is Hep B virus

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23
Q

Adenovirus

A

not enveloped, DS, linear; febrile pharyngitis, acute hemorrhagic cystitis, pneumonia, conjunctivitis (“pink eye”)

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24
Q

parvovirus

A

non-enveloped, SS, linear (smallest DNA virus); B19 causes aplastic crisis in sickle cell disease, “slapped cheeks” rash in ids (erythema infectiosum or fifth disease); RBC destruction in fetus leads to hydrops fetalis and death, in adults leads to pure RBC aplasia adn rheumatoid arthriits-like sx

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25
Q

papillomavirus

A

non-enveloped, DS, circular, causes warts (serotypes 1,2,6,11), CIN and cervical cancer (types 16, 18)

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26
Q

polyomavirus

A

not enveloped, DS and circular; JC virus cases PML in HIV patients; BK virus can be seen in transplant patients and commonly targets the kidney

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27
Q

poxvirus

A

enveloped, DS and linear (largest DNA virus); smallpox eradicated by use of live attenuated vaccine; cowpox causes “milkmaid blisters”; molluscum contagiosum causes flesh-colored papulewith central umbilication

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28
Q

HSV-1

A

gingivostomatitis, keratoconjunctivits, herpes labialis, temporal lobe encephalitis; transmitted by respiratory secretions

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29
Q

HSV-2

A

herpes genitalis, neonatal herpes; Latent in sacral ganglia; transmitted by sex contact, perinatally

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30
Q

VZV

A

chickenpox, shingles, encephalitis, pneumonia; latent in dorsal root or trigeminal ganglia; most common complication of shingles is post-herpetic neuralgia; transmitted by resp secretion

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31
Q

EBV

A

mono (fever, hepatosplenomegaly, pharyngitis, and lymphadenopathy, esp posterior cervical lymphadenopathy); transmitted by resp secretions and saliva; infects B cells through CD21; atypical lymphocytes seen on peripheral blood smear are not infected B cells but rather reactive T cells; detect by monospot test (heterophile antiboides); assoc with lymphomas and nasopharyngeal carcinoma

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32
Q

CMV

A

congenital infection, mono (but negative monospot test), pneumonia, retinitis; infected cells have characteristic “owl eye” inclusions; latent in mononuclear cells; transmitted congenitally and by transfusion, sex contact, saliva, urine, transplant

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33
Q

HHV-6/HHV-7

A

roseola; high fevers for several days that can cause seizures, followed by a diffuse macular rash; transmitted by saliva

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34
Q

HHV-8

A

Kaposi sarcoma (neoplasm of endothelial cells); seen in HIV/AIDS and transplant pts; dark/violaceous plaques or nodules representing vascular proliferations; cal also affect GI tract and lungs; transmitted by sexual contact

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35
Q

HSV indentification

A

Viral cx for skin/genitalia; CSF PCR for herpes encephalitis; Tzanck test (smear of opened kin vesicle to detect multinuc giant cells commonly seen in HSV-1, HSV-2 and VZV infection); intranuclear inclusions also seen with HSV-1, HSV-2, VZV

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36
Q

rotavirus

A

RNA virus; numbe r1 cause of fatal diarrhea in kids

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37
Q

coltivirus

A

RNA; colorado tick fever

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38
Q

PicoRNAviruses

A

poliovirus, echovirus, rhinovirus, coxsackievirus, HAV

39
Q

echovirus

A

aseptic meningitis

40
Q

rhinovirus

A

common cold

41
Q

coxsackievirus

A

aseptic meningitis, herpangina (mouth blisters, fever); hand, foot and mouth disease; myocarditis and pericarditis

42
Q

norovirus

A

viral gastroenteritis

43
Q

what are the flaviviruses

A

hep C virus, yellow fever, dengue, st. louis encephalitis, west nile virus

44
Q

coronavirus

A

common cold and SARS

45
Q

orthomyxovirus

A

influenza virus

46
Q

paramyxoviruses

A

paraflu (croup), RSV (bronchiolitis in babies, treat with ribavirin); measles; mumps

47
Q

rhinovirus

A

a picoRNAvirus; nonenveloped RNA virus; cause of common cold; over 100 seologic types; acid labile (destroyed by stomach acid, therefore does not infect the GI tract, unlike other picornavirses)

48
Q

yellow fever virus

A

a flavivirus (also an arbovirus) transmitted by Aedes mosquitoes; sx are igh fever, block omitus, and jaundice. May see Councilman bodies (eosinophilic apoptotic globules) on liver bx

49
Q

rotavirus

A

infantile gastroenteritis; segmented dsRNA virus; acute diarrhea in the winter (esp day care center); villous destruction with atrophy leads to decreased absorption of sodium and loss of potassium; CDC recommends routine vaccination of all infants

50
Q

influenza viruses

A

orthomyxoviruses; enveloped, neg ssRNA viruese with 8-segment genome; contains hemagluttin to promote viral entry and neuraminidase to promote progeny virion release

51
Q

genetic shift/antigenic shift

A

causes pandemics; reassortment of viral genome segments, such as when segments of human flu A virus reassort with swine flu A virus

52
Q

genetic drift/antigenic drift

A

causes epidemics; mino (antigenic dift) changes based on random mutation in hemagluttinin or neuraminase genes

53
Q

rubella virus

A

a togavirus; causes rubella (aka german measles); fever, post-auricular and other lymphadenopathy, arthralgias, and fine rash; causes mild disease in children but serious congenital disease (TORCH infxn)

54
Q

congenital rubella findings

A

blueberry muffin baby, indicative of extramedullary hematopoesis

55
Q

rubella rash in a kid

A

fine, confluent macules that start on the face and spread centrifugally to involve the trunk and extremities

56
Q

paramyxoviruses

A

usually affects kids; paraflu (croup), mumps, measles, RSV (bronchioltis, pneumonia); all contain surface F (fusion) protein, which causes resp epithelial cells to fuse and form multinuc giant cells; Palivizumab (monoclonal antibody against F protein) prevents PNA caused by RSV in premature infants

57
Q

Croup

A

aka acute laryngotracheobronchitis; caused by paraflu; barking cough, inspiratory stridor; narrowing of upper trachea and subglottis leads to steeple sign on Xray; severe croup can result in pulsus paradoxus 2/2 upper airway obstruction

58
Q

measles

A

rubeola virus; fever, cough, coryza, and conjunctivitis then eventually Koplik spots, followed by a maculopap rash that starts at the head/neck and spreads down; Lymphadenitis with Warthin-Finkeldey giant cellsin a background of paracortical hyperplasia; subacute sclerosing panencephalitis, occuring years later; encephalitis; giant cell pneumonia are possible sequelae

59
Q

koplik spots

A

bright red sports with blue/white center on buccal mucosa that precedes the measles rash by 1-2 days

60
Q

Vit A supplementation in measles

A

can reduce mortality in infants with malnutrition in kids who get measles

61
Q

mump’s virus

A

uncommon, due to MMR vaccine; symptoms are parotitis, orchitis, and aseptic meningitis; can cause sterility (esp after puberty)

62
Q

rabies virus

A

bullet-shaped virus; Negri bodies commonly found in purkinje cells of cerebellum na din hippocampal neurons; rabies has long incubation period (weeks to months) before sx onset; travels to the CNS by migrating in a retrograde fashion up nerve axons after binding to ACh receptors; disease progresses from fever to agitation, photophobia, hydrophobia, hypersalivation to paralysis and coma to death; post exposure prophylaxis is wound-cleaning plus immuniz with killed vaccine and rabies immunoglobulin; most commonly from bat, racoon, and skunk bites

63
Q

ebola virus

A

filovirus that targets endothelial cells, phagocytes, hepatocytes; abrupt onset of flu-like sx, d/v, fever, myalgias; con progress to DIC, diffuse hemorrhage, shock; high mortality rate, no definitive treatment; supportive care

64
Q

Hep A virus

A

RNA picoRNAvirus; fecal-oral; no HCC risk; usually asymptomatic

65
Q

Hep B virus

A

DNA hepadnavirus; parenteral, sexual, perinatal transmission; yes HCC risk

66
Q

Hep C virus

A

RNA flavivirus; primarily blood transmission (IVDU), HCC risk

67
Q

Hep D virus

A

RNA delta virus; parenteral, sexual, perinatal transmission (just like Hep B); dependent on Hep B

68
Q

Hep E virus

A

RNA hepevirus; fecal-oral transmission, esp waterborne; high mortality in pregnant women

69
Q

Signs and sx of all hepatitis viruses

A

fever, jaundice, increased AST and ALT; may see Councilman bodies (eosinophilic apoptotic globules) on liver bx

70
Q

HBeAg

A

A second, different antigenic determinant in the HBV core (aside form HBcAg) that indicates active viral replication and therefore high transmissibility

71
Q

Anti-Hbe

A

antibdy to HBeAg; indicates low transmissibility

72
Q

ALT and AST in viral versus alcoholic hepatitis

A

in viral, ALT>AST; in alcoholic, AST>ALT

73
Q

important diagnostic test in the incubation period

A

HBsAg

74
Q

important test in the prodrome or acute disease

A

HBsAg and anti-HBc

75
Q

diagnostic test in early convalescence

A

anti-HBc

76
Q

diagnostic test in late convalescence

A

Anti-HBs and anti-HBc

77
Q

What can you detect in the acute hep B infection?

A

HBsAg and HBeAg and IgM of anti-HBc

78
Q

what can you detect in the “window” period?

A

HBeAg and anti-HBc IgM

79
Q

what can you detect in the chronic HBV with high infectivity?

A

HBeAg, HBsAg, ant-HBc IgGi

80
Q

what can you detect in chronic HBV with low infectivity?

A

HBsAg, anti-Hbe, and anti-HBc IgG

81
Q

what can you detect in recovery period

A

anti-HBs, anti-Hbe, anti-HBc IgG

82
Q

what can you detect in the immunized patient?

A

anti-HBs

83
Q

structure of HIV

A

diploid genome (2 molecules of RNA); structural genes are gp120 (attachment to host CD4 T cells) and gp41 (fusion and entry) and p24 (capsid protein) and pol (reverse transcriptase, aspartate protase, integrase); virus binds CD4 as well as coreceptor, either CCR5 on macrophages (early infxn) or CXCR4 on T cells (late infection)

84
Q

if a patient has a homozygous versus heterozygous CCR5 mutation

A

homozyg gives you immunity; heterozyg gives you slower course of disease

85
Q

HIV dx

A

first do ELISA; if pos, confirm by Western blot; both of these tests look for antibodies to viral proteins, so are often falsely neg in the first 1-2 mos of infxn and falsely pos initially in babies born to infected mothers (anti-gp120 crosses placenta)

86
Q

AIDS diagnosis alternative

A

CD4 percentage less than 14%

87
Q

Opportunistic infections in patients with CD4 count less than 500

A

candida (oral thrush), EBV (oral hairy leukoplakia), bartonella henselae (bacillary angiomatosis), HHV-8 (Kaposi sarcoma), Cryptosporidium (chronic, watery diarrhea), HPV (squamous cell carcinoma, commonly of anus or cervix

88
Q

Opportunistic infections in patients with CD4 count less than 200

A

toxoplasma (brain abscess), HIV dementia, JC virus reactivation (PML), PCP pneumonia

89
Q

Opportunistic infections in patients with CD4 count less than 100

A

aspergillus (hemoptysis, pleuritic pain), crytpococcus neoformans (meningitis), cadida albicans (esophagitis), CMV (retinits, esophagitis, colitis, pneumonitis, encephalitis), EBV (B cell lymphoma), histoplasma (fever, weight loss, cough, vomitting, diarrhea), MAC (nonspec systemic sx or focal lymphadenitis

90
Q

Prions

A

conversion of normal protein to a beta pleated form, which is transmissible via CNS-related tissue (iatrogenic CJD) or food contaminated by BSE-infected animal products; resistant to standard sterilizing procedures, including autoclaving; leads to spongiform encephalopathy and dementia, ataxia, and death

91
Q

Creutzfeldt-Jakob disease

A

rapidly progressive dementia, typically sporadic (some familial forms)

92
Q

Bovine spongiform encephalopathy (BSE)

A

also known as mad cow disease

93
Q

Kuru

A

acquired prion disease noted in tribal populations practicing human cannibalism

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