Viruses II Flashcards

1
Q

two groups of GI viruses and one e.g. for each

A

fecal-oral but no diarrhea (polio)

diarrhea as primary sign (restricted to gut, don’t disseminate, little cytopathology, toxin involved)

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2
Q

viruses that don’t cause diarrhea; characteristics

A

picornaviridae (enterovirus, rhinovirus)

high titers in GI trace, disseminate, asymptomatic/mild, very hardy, stable at pH 3, sensitive to Cl and formaldehyde, but HEAT-sensitive

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3
Q

major enterovirus syndromes

which virus causes peri/myocarditis?

A
mild, self-limiting illness w/rash
colds
aseptic meningitis
pericarditis/myocarditis (COXACKIE)
paralysis
hepatitis
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4
Q

Polio
can you regain some fxn?
peak?
vaccine?

A

2wk incubation
causes aseptic meningitis (if 2ndary viremia high enough or persists long enough to cross BBB) or subclinical infxn
enters via Peyer’s/M cells
all enteroviruses enter this way
can regain some fxn (limb paralysis in elderly bc can’t compensate as well)
peak in late summer
yes

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5
Q

hepatitis A

vaccines to whom?

A

28 days
abd pain, fatigue, inc LFT’s, dark urine, jaundice, NV
similar sx for other hep viruses
likelihood of sx depends on age (l travelers, men sex w/men, drug users, occup risk, chronic liver disease

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6
Q

big syndrome assoc?

A

coxackie and cardiomyopathy

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7
Q

viruses causing diarrhea

A

1: rotavirus

astrovirus, norovirus (leading cause of hospitalized diarrhea), adenovirus, coronavirus
resistant to low pH

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8
Q

someone comes in w/respiratory infection w/assoc diarrhea think which virus?

A

coronavirus

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9
Q

viruses that can also transmit via: airborne (e.g.) and vomitus (e.g.)

A

airborne: norovirus
vomitus: astroviruses

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10
Q

rotavirus

syndrome, season, sero

A

acute GE in kids 4 are sero+

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11
Q

astrovirus

syndrome, season, sero

A

acute GE in kids
winter
75% of kids 3-4 are sero+

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12
Q

norovirus

syndrome, season, sero

A

acute GE in kids/adults
no seasonality
explosive outbreaks in schools/ships/institutions

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13
Q

adenovirus

syndrome, season, sero

A

infants/kids
no seasonality
sporadic outbreaks

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14
Q

coronavirus

syndrome, season, sero

A

children <1y

diarrhea assoc w/ respiratory infection

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15
Q

pathogenesis of diarrhea causers

A
1-3d incubation
abrupt vomiting, diarrhea (watery; usually no blood), cramping
headache, myalgia, low grade fever
little inflammation/cell death
shortening of microvilli
toxins from rota/astro
sx restricted to GI tract
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16
Q

mucus in stool

A

coronavirus

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17
Q

toxins of rotavirus/astrovirus

A

Rota: NS4 –> activates acyclase
Astro: capsid –> actin cytoskeleton opening cell/cell jxns

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18
Q

prevention/tx for diarrhea causing viruses

A
hygiene
clean water/food
NO ANTIVIRALS
supportive for self-limiting
HYDRATION
DO NOT use agents that reduce peristalsis
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19
Q

rotavirus vaccine

A

human and bovine strains
no preservatives of thimerosal
incidence has dropped ever since

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20
Q

rotavirus vaccination for those after 12 weeks of age?

A

no b/c probably already exposed to the infection

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21
Q

croup

A

cough that sounds like child can’t breathe

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22
Q

how come we don’t have a vaccine for the common cold?

A

there’s too many of them

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23
Q

characteristics of respiratory viruses

3 sx of LRT infection?

A

all can cause sx in URT
several can cause LRT (bronchitis, croup, bronchopneumonia)

e.g. RSV, can start in URT, but then progress to LRT (see pt back if gets worse)

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24
Q

takehome on seasonal incidence?

A

can’t use this info to determine etiologic agent (peaks overlap)

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25
Q

influenza characteristic sx

A

fever (104); myalgia, fatigue, headache (notice not many resp sx)

abrupt sx after 1-2 day incub
fever/myalgia/malaise dry cough, sore throat, nasal congestion, rhinorrhea not prominent

systemic sx last 3-5d; resp sx last 3-4d longer and recovery of lung fxn can take weeks

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26
Q

influenze progression

risky groups?

A

dyspnea/cyanosis w/hypoxia
no lobar consolidation on CxR
kids/elderly/lung disease/heart disease/pregnant women

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27
Q

antivirals for influenza

A

amantidine/rimantidine: bind to M2 ion channel block viral entry into cells *(most strains are now resistant to this)

tamiflu/relenza: inhibit neuraminidase blocking release from cells (tamiflu is preferred currently of all)

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28
Q

secondary bacterial pneumonia
3 most common bugs?
most common in which pts?

A

classic flu w/improvement followed by fever, cough, sputum, consolidation on CxR

S. pneumonia, S. aureus, H. flu
elderly and lung disease

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29
Q

reassortment causes?
viruses that do this have what?
e.g.?

A

worldwide pandemics
only in viruses w/segmented genomes, occurs when two strains infect same cell
influenza

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30
Q

pandemic strains happen via what specific reassortment event?

A

hemagglutinin gene –> population has not seen new HA protein and thus is not protected

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31
Q

influenza reassortment detail

primarily a virus of which animal?

A

Hemagg and neuraminidase are major envelope proteins

waterfowl (birds)

pandemic reassortment –> new bird HA jumping into human strain

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32
Q

antigenic shift?

drift?

A

shift: reassortment that introduces a new gene sigmate into a circulating human flu strain
drift: pt MUT in current human flu strain that alters virulence; the reason for revaccination (along with protection not lasting that long)

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33
Q

avian strain v. human strain differences

A

avian: a2,3 sialic acid
human: a2,6 silica acid

pigs have both

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34
Q

influenza vaccine

A

killed virus v live strain (mist)
mist not for >50 or <5, pregnant women
protective for one year only
reduced efficacy in elderly

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35
Q

RSV

A
kids 6mo-1y (boys hospitalized)
lethal in >65 and COPD
2-8d incubation, nasal cong, ST, fever (less than flu), cough, then dyspnea/wheezing
IS infiltrates/hyperinflation on CxR
bronch/pneumo/croup is rare
OM/sinusitis can complicate
36
Q

RSV therapy for whom?

A

ribivarin for hospitalized infants
steroid combo
RSV Ig in premature infants in first year
palivizumab-mAb against F protein in high risk kids

37
Q

parainfluenza which types cause disease?

A
types 1 and 2
2-7d
sometimes bronchitis, low grade fever 2-3d
TYPES 1 and 3 --> croup
TYPE 3 --> pneumo/bronchiolitis
TYPE 4 --> rarely severe illness
38
Q

PIV therapy

A

no antivirals/vaccine
support
hospitalization for croup
O2 and ventilation

39
Q

SARS CoV

A

2-7d of mild URT sx
then fever, rigors, dry cough, dyspnea, malaise, headache, flu-like illness
27% have diarrhea
ARDS

40
Q

rhinovirus

A

responsible for 2.3 colds/yr
smoking does not predispose, BUT results in more severe sx, no gender diffs
high 90% rate of symptomatic infxn
sneezing, runny nose, ST, cough, nasal congestion, headache, little/no fever
exacerbates asthma and bronchitis via EOS in lungs
OM/sinusitis complications

41
Q

rhino tx

A

OTC antihistamines/decongestants, no antivirals, VitC, Zinc, Echinacea

42
Q

adenovirus

A
most infected by age 10
latent in adenoids/tonsils
boot camps
infants: cough/ST
kids: ST/tracheitis
YA: more severe cough, fever, ST, runny nose
adults: cold
can progress to pneumonia
43
Q

adenovirus tx

A

no antivirals

vaccine: encapsulated types swallowed to cause asymptomatic gut infxn to establish immunity (WILD TYPE strains used)

44
Q

adeno pathogenesis (same in SARS, MERS, avian)

A

replicate in resp epith cells –> death/sloughing
debris clog airways
cytokines –> aches, fever, malaise (diff viruses –> diff cytokines –> diff sx)
inflammation of airways
edema and ARDS

45
Q

alpha HHV
Beta HHV
gamma HHV

neurotrophic
lymphotropic

A

HSV-1/2, VZV
HCMV, HHV-6/7
EBV, HHV-8

alpha
beta and gamma

46
Q

defining criteria of latency?

what happens during this period?

A

can’t detect infectious virus

virus replication shuts down but persists in genome of cell nucleus

47
Q

2 outcomes of reactivation?

A

sx disease

asymptomatic shedding in the absence of any sx

48
Q

sites of latency

HSV/VZV/HCMV/EBV/HHV

A
HSV 1/2: neurons
VZV: neurons
HCMV: monocytes
EBV: B cells
HHV 6/7: CD4 T
HHV 8: maybe B's
49
Q

only gene expressed during latency?

A

latency associate transcript

50
Q

EBV latency proteins

A

for latent viruses in non-dividing cells: allows the viral genome to replicate along with cell and segregate into daughter host cells (LYMPHOTROPIC VIRUS)

51
Q

what’s cool about EBNA 1?

A

can’t be processed and put on MHC-1 molecules

52
Q

reactivation triggers?

A
stress
UV light
steroid hormones
trauma to ganglia
decr immune fxn
53
Q

difference between simplex and zoster? what else is unique about zoster transmission?

A

zoster causes disseminated infection

can be spread by aerosol, otherwise close contact

54
Q

exception to the rule of viral epidemiology (which is not positive in >50% of individuals?)

A

HHV-8

55
Q

HSV-1/2 primary diseases (which are recurrent?*)

A
gingivostomatitis
keratoconjunctivitis*
cutaneous herpes (gladiatorum)*
genital herpes*
encephalitis*
aseptic meningitis*
neonatal herpes

herpes labialis* (only recurrent)
keratoconj: each reactivation immune resp causes more dmg to eye

56
Q

how do we dx HSV?

A
PCR
PCR on CSF for encephalitis
culture w/IF
can do Tzanck stain
watch for neuro sx in encephalitis
57
Q

jaundice, hepatosplenomegaly, microcephaly, petechial rash, mental retardation, chorioretinitis

A

congenital cytomegalic inclusion disease

sx more severe when infection occurs earlier in pregnancy

58
Q

primary HCMV infections

HCMV reactivation infections

A

heterophile negative mono
hepatitis
cong cytomegalic inclusion disease

none in immunocompetent
suppressed:
donor organs can transmit
BMT: IS pneumonia
hepatitis in liver transplant pts
kidney infection
Retinitis in AIDS pts --> blindness
59
Q

dx HCMV

A

saliva: owl eye cells
immunostain for antigens
PCR
no cultures - grows slowly

60
Q

EBV primary infections

A

infectious mono (heterophile +: can detect this antigen for dx)
hepatitis
encephalitis (rare)
immunocompetent: no known reactivation disease
compromised: lymphoma and oral hairy leukoplakia (AIDS pts)

61
Q

fever, ST, lymphadenopathy, tonsular exudate, palatal petechiae, heterophile antibodies

A

EBV mono

dx: monospot test or viral spec antigen

62
Q

cancer in kids between 6-15y
jaw and long bones
assoc w/Malaria

A

EBV: Burkitt’s lymphoma

63
Q

EBV cancers

A

Burkitt’s

Nasopharyngeal

64
Q

mechanism of EBV and cancer

A

infects B cells and induces proliferation –> accum mutations in proto-oncogenes; Ig rearrangement –> chromosomal translocations (Cmyc) –> malignant transformation

65
Q

EBV dx

triad of sx?

A
ST, fever, lymphadenopathy
monospot test
heterophile antibody + to sheep blood cells
Downey T cells
immunostaining
no culture
biopsies for solid tumors
66
Q

roseola infantum caused by

A

HHV-6
self-limited febrile illness w/mild macular rash
only a problem if immunosuppressed

67
Q

KHSV (HHV-8)

A

only if immunocompromised
Kaposi’s (AIDS and elderly) and Castleman’s
primary transmission: SEXUAL contact

68
Q

KHSV dx?

A

Kaposi lesions: multifocal purple spots, PVR/immunostain/serology

69
Q
antivirals:
HSV1,2/VZV
HCMV
EBV
HHV-6
HHV-8
A

trifluorthymidine/idoxuridine topical; acyclovir, valayclovir, famciclovir

foscarnet, ganciclovir

acyclovir, valacyclovir

ganciclovir

IFN, radiation/cytotoxics for cancer; restore immune system

70
Q

mosquito-borne viruses

A

western/eastern equine encephalitis virus
st. louis encephalitis virus
california group enceph virus (LaCrosse in this group)
Colorado Tick Fever virus

71
Q

mosquito-borne diseases

A

dengue: hemorrhagic (carribean/latin america)
venezuelan equine ecephalitis
yellow fever: hemorrhagic
chikungunya: arthritis (carribean)

72
Q

animal borne viruses

diseases?

A

rabies, hanta, sin nombre
lassa fever: hemorrhagic (rodents)
ebola: hemorrhagic (bats)

73
Q

ebola virus: presentation

A

fever, malaise, myalgia, headache –> pharyngitis, vomiting, diarrhea, mac-pap rash –> hmorrhagic diathesis and multiple organ failure –> death in 7-10d

74
Q

urban transmission pattern

e.g.?

A

requires high titer to maintain cycle; prolonged viremia in vertebrate host
maintained in urban settings where humans are reservoir
e.g. Yellow Fever

75
Q

Sylvan (wild) cycle

e.g. yellow fever cycle involves?

A

multiple reservoirs: birds, snakes, small mammals –> mosquito –> humans offshoot from cycle (i.e. get infected during a hike)

yellow fever: monkeys –> mosquito –> monkeys

76
Q

animal-borne diseases

A

encephalitis (repl in CNS)
fever/hemorrhagic fever (repl in BV endothelium –> cytokines –> hypovolemic shock)
arthritis
yellow fever (repl in hepatocytes –> failure to produce clotting factors –> hemorrhage and vomiting blood
pulm hantavirus syndrome (repl in lungs –> ARDS –> edema

77
Q

therapy for animal-born infections

A

no antivirals

can try ribivirin in life-threatening cases, or human IvIg

78
Q

available vaccinations

A

yellow fever: live for travelers
rabies: killed for humans, live for animals (IvIg used in exposures)
horses for encephalitis

79
Q

papillomaviruses: 2 types of disease

which four to remember? (are in current vaccine)

A

dsDNA, NON-enveloped, icosahedral

warts, cancer

HPV-6,11,16,18 –> cause genital warts

16,18 will much more frequently progress to cervical cancer

80
Q

cancer w/papillomaV?

A

need cofactors –> additional mutations

81
Q

90% of H&N cancers caused by?

A

HPV-16

82
Q

does the DNA integrate in a normal papilloma infection?

A

no

83
Q

What does E7 do?

A

binds Rb and removes E7 from cytoplasm –> cell continues to divide (when cell continues to divide triggers DNA damage response, mediated by p53)

BUT E6 eliminates p53 (removes cell brake)

84
Q

papilloma dx

A
appearance
PAP smear
colposcopy
acetowhite staining
PCR
85
Q

parapox virus
causes umbilicated papules on skin
if immunocompromised can spread and be mistaken for squamous cell carcinoma

A

molluscum contagiosum

86
Q

polyomavirus (just need to know BK and JC)

A

JC virus –> progressive multifocal leukoencephalopathy
BK virus –> kidneys (can shed in urine), graft failure

both cause latent infxns
only cause above problems in IMMUNOCOMPROMISED pts

87
Q

Parovirus B19 disease

A

Fifth Disease (slapped cheek)
Polyarthropy
Transient Aplastic crisis (pts w/increased erythropoiesis: replicates in hemapoetic precursor cells)
Hydrops Fetalis (congenital anemia)
Persisent anemia in immunocompromised pts