viral basics

Question 1

type of recombination with viruses with a segmented genome (only RNA viruses)
2 strains of same virus infect same cell → exchange intact genetic SEGMENTS→ limited epidemic, world-wide pandemic
i.e., RNA influenza

Answer 1

reassortment

Question 2

2 viruses infect same cell → exchange GENES between 2 chromosomes in regions of genetic homology → viral progeny are not like parent viruses
i.e., DNA viruses or RNA viruses with DNA phase (retroviruses)

Answer 2

recombination

Question 3

2 viruses infect same cell - one virus has a mutation → makes non-functional protein but nonmutated virus can make a functional protein that can allow the mutated virus to replicate itself
mutated virus can only replicate through complementation: infect host cell or another virus can provide functional protein

Answer 3

complementation

Question 4

2 viruses infect same cell → progeny virions receive surface proteins from 1 or both parent viruses → alters tissue type the virus can infect but the genetic material inside only came from 1 of the parents (no change to genetic material) → progeny will have the coat coded by genetic material

Answer 4

phenotypic mixing

Question 5

number of copies of RNA or DNA present in virion

all DNA and RNA viruses are haploid (only 1 copy) EXCEPT retrovirus (2copies of ssRNA)

Answer 5

virus ploidy

Question 6

contain live virus but weakened → subclinical infection to allow for humoral + ROBUST cell-mediated immunity
long-lasting immune response
rare: attenuated vaccine reverted to wild-type

Answer 6

live attenuated vaccine

Question 7

from whole, killed virus
humoral + cell-mediated (not as robust)
may need BOOSTER

Answer 7

killed virus vaccines

Question 8

use specific viral antigens to stimulate immune response

Answer 8

subunit viral vaccines

Question 9

enveloped DNA virus
latent infection in host cell
reactivation disease after recovery from acute infection

Answer 9

8 human herpesviruses (HHV)

Question 10

lab test to detect HSV-1 or HSV-2 or VZV

Answer 10

Tzanck smear: multinucleated giant cells = + test (one of these viruses)
low specificity and sensitivity
scrape base of open vesicle

Question 11

type A cowdry bodies or type 1 cowdry inclusions

Answer 11

intranuclear eosinophilic inclusions seen in

HSV-1 or HSV-2 or VZV

Question 12

symptoms of mono (fever, sore throat, posterior cervical LAD - painful, exudative pharyngitis) but
- heterophile test (monospot)
no EBV antibodies

Answer 12

CMV infection (most common)
acute HIV
acute toxoplasmosis
viral hepatitis
strep throat

Question 13

EBV associated malignancies: EBV is latent inside body and contributes to cancer

Answer 13

Hodgkin lymphoma: 50% cases
burkitt lymphoma
nasopharyngeal carcinoma
diffuse large cell lymphoma
oral hairy leukoplakia
lymphoproliferative disorders

Question 14

owl’s eye nuclear inclusions

Answer 14

CMV

Question 15

causes roseola (sixth disease/exanthema subitum vs parvovirus B19 = fifth disease) in children
almost all infected by 2 yo

Answer 15

HHV-6

Question 16

3-5 days of high fever (>102 F) → then, body-wide maculopapular rash
latent infection - no known concerns
complication: febrile seizures

Answer 16

roseola from HHV-6

Question 17

roseola-like infection (but later in life)
latent infection - no known concerns
all infected by 5 yo

Answer 17

HHV-7

Question 18

5% total U.S. population infected
MSM - prevalence is much higher
infects spindle cells coming from vascular and lymphatic endothelial tissue (inner lining of blood vessels and lymphatic vessels)
highly vascular tumors:
purple lesion on skin +/- organ systems (lung (hemoptysis): nodule on chest CT)

Answer 18

HHV-8 (kaposi sarcoma-associated herpesvirus)

Question 19

treatment of HHV-8 (kaposi sarcoma-associated herpesvirus)

Answer 19

HAART (HIV retroviral therapy)
topical agents: alitretinoin
intralesional: vinblastine
liposomal anthracyclines: daunorubicin, doxorubicin

Question 20

types of HHV-8 (kaposi sarcoma-associated herpesvirus)

Answer 20

classic: slow-growing tumor without much potential for mets
epidemic: found in HIV/AIDs patients
immunocompromised: transplant patients

Question 21

latent herpes virus locations

Answer 21

HSV-1: trigeminal ganglia
HSV-2: sacral ganglia
VZV: dorsal root or trigeminal ganglia
CMV: mononuclear cells
EBV: B cells

Question 22

downey cells: foamy cytoplasm

Answer 22

T cells that respond to EBV infected B cells

Question 23

REASSORTMENT of viral genome
1 pig infected with 2 influenza A viruses: 2 virus genomes can exchange genetic material
between human and pig viruses → now pig genetic material in human virus →infect humans → no preexisting immunity for pig virus in humans → PANDEMIC

Answer 23

genetic shift

“oh SHIFT***” = bigger deal

Question 24

genes become mutated or rearranged
small changes in influenza virus every year (reason for seasonal VACCINE) → immune system can better handle → seasonal EPIDEMICS

Answer 24

genetic drift

Question 25

trivalent flu vaccine components

Answer 25

2 influenza A
1 influenza B
chosen based on pattern of flu infections over last year

Question 26

quadrivalent flu vaccine components

Answer 26

2 influenza A

2 influenza B

Question 27

intranasal flu vaccine

Answer 27

live attenuated virus
intranasal
healthy, non-pregnant adults: 2-49 yo

Question 28

injectable flu vaccine

Answer 28

killed virus

Question 29

effectiveness of flu vaccine depends on

Answer 29

typical effectiveness at preventing infection: 60-80%
also ↓ disease severity
effectiveness depends on:
age of person
immune system
when received: takes 2 weeks for Abs to develop
how well matched to strains

Question 30

age recommended to get flu shot

Answer 30

equal to or greater than 6 mo

Question 31

winter infections

Answer 31

influenza: flu
rotavirus: diarrhea in kid
RSV: bronchiolitis in kid

Question 32

summer infections

Answer 32

1) enterovirus:
poliovirus
echovirus
coxsackievirus
2) arbovirus:
west nile virus

Question 33

hepatitis C treatment

Answer 33

ribavarin

INFα

Question 34

illnesses spread by rodent urine

Answer 34

RNA viruses:
hantaviurs
lassa virus
LCM virus
bacteria:
leptospirosis