Viruses

Question 1

viral RNA-dependent RNA polymerase

Answer 1

required for (-) reading frame

Question 2

reverse transcriptase

Answer 2

RNA-dependent DNA polymerase

Question 3

orthomyxovirus

Answer 3

influenza

ssRNA, envelope w/ surface glycoproteins hemagglutinin (H) and neuraminidase (N)

Question 4

paramyxoviruses

Answer 4

ssRNA with envelope
parainfluenza, mumps, measles, respiratory syncytial virus, human metapneumovirus
produce multinucleated giant cells (syncytia) via fusing factor

Question 5

1. human metapneumovirus

Answer 5

common cold, bronchiolitis, pneumonia

paramyxovirus

Question 6

2. parainfluenza

Answer 6

flu-like, most common cause of croup laryngothracheobronchitis (barking cough, steeple sign)

Question 7

3. respiratory syncytial virus

Answer 7

infections in upper and lower respiratory tracts, nose, eyes, mouth.
#1 cause of pnuemonia in infants

Question 8

4. mumps virus

Answer 8

enters salivary secretions via pharynx or conjunctiva
painful enlargement of salivary glands
epididymoorchitis in males
MMR live vaccine

Question 9

5. measles virus (rubeola)

Answer 9

koplik spots
inclusion body encephalitis
subacute sclerosing panencephalitis
93.3% vaccinated = herd immunity
Warthin-Finkeldey cells

Question 10

Hepatitis viruses

Answer 10

A and E are fecal-oral transmission
B, C, and D parenteral/sex transmitted
B is dsDNA
ACDE are ssRNA

Question 11

Hep A

Answer 11

infectious
fecal-oral transmission
subclinical to fulminant hepatitis with rare chronic state

Question 12

Hep B

Answer 12

Dane particle
ds DNA
+/- hepatocellular carcinoma

Question 13

Hep C

Answer 13

subclinical to mild chronic carrier state

hepatocellular carcinoma

Question 14

Hep D

Answer 14

delta antigen

requires prior infection with Hep B

Question 15

Hep E

Answer 15

enteric

similar to A, Asia and Africa

Question 16

Viral hepatitis Dx

Answer 16

A: anti-Hep A IgG and IgM
B: surface Ag (HBsAg), surface antigen Ab (HBsAb), core Ab (HBcAb), and e Ag (HBeAg)
C: anti hep C Abs and HCV RNA
D: anti delta Abs (anti-HDV)
E: anti hep E Abs and HEV-RNA

Question 17

Viral hepatitis Rx

Answer 17

Hep A and B vaccines

Question 18

papovariedae; papillomaviridae HPV

Answer 18

E6 inhibits p53 protein
E7 inhibits pRB
High risk types: 16 and 18 (involved in most cancers and high grade dysplasias

Question 19

adenoviridae

Answer 19

acute respiratory disease
gastroenteritis
live adenovirus vaccine

Question 20

parvovirus

Answer 20

erythema infectiosum (5th disease)
aplastic anemia (infects erythroblasts)
hydrops fetalis w/ in utero infection

Question 21

arboviruses

Answer 21

Arthropod borne
Togaviradee
Flaviviradae
Bunyaviradae

Question 22

Togaviruses

Answer 22

Alphaviruses
1. Chickengunya
2. Eastern and western equine encephalitis
Rubivirus: Rubella (TORCH syndrome)
Flaviviruses
4. yellow fever, dengue, St. Louis encephalitis, Japanese encephalitis, West Nile virus, Hep C virus
Bunyaviruses
5. California encephalitis, hantavirus

Question 23

Rubella/rubivirus

Answer 23

German measles: usually mild, 3 days

Congenital rubella syndrome: affects eyes, heart, brain

Question 24

Flaviridae

Answer 24

1. St.Louis encephalitis (SLE)
2. West Nile encephalitis (WNE)
3. Yellow fever
4. Dengue fever

Question 25

picornaviruses

Answer 25

Heparnavirus
Rhinoviruses: attach to ICAM-1 receptor to respiratory epithelial cells
Enteroviruses: poliovirus, coxsackievirus, echovirus: fecal-oral transmission

Question 26

poliovirus

Answer 26

absorb to intestinal epithelial cells and motor neurons of CNS

Question 27

coxsackie

Answer 27

Group A: herpangina, acute hemorrhagic conjunctivitis, hand-foot-mouth disease
Group B: pleurodynia, myocarditis, pericarditis, hepatitis

Question 28

echoviruses

Answer 28

respiratory disease, aseptic meningitis, paralytic disease

Question 29

rhabdovirus/rabies

Answer 29

Bullet-shaped virus
Encephalitis via ACh receptor w/ retrograde axoplasmic transport to DRG and spinal cord
Neurons accumulate Negri bodies
Once symptomatic, death is almost certain

Question 30

retroviruses

Answer 30

reverse transcriptase
Oncoviruses: HTLV I, HTLV 2
HTLV 1: T cell lyphoma/leukemia
Lentiviruses: HIV 1, HIV 2, can cause fusion of macrophages (multinucleated cells)
Attach to CD4 and CCR5 (macrophage) or CXCR4 (T helper cell) coreceptors

Question 31

HIV Dx

Answer 31

Serology for HIV Abs

Western blot for Abs against viral proteins

Question 32

HIV genes

Answer 32

gag (p24): early marker of infection
pol: reverse transcriptase, integrase, protease
env (gp120): binds CD4 and CCR5/CXCR4
tat: upregulates transcription
rev: upregulates production of gag, pol, and env
nef: decreased CD4 and MHC I expression on host cell

Question 33

Herpesviruses

Answer 33

intracellular inclusions and multinucleated giant cells

capable of latency

Question 34

HHV 1

Answer 34

herpes simplex 1
cold sores
have intranuclear acidophilic Cowdry type A inclusions

Question 35

HHV 2

Answer 35

herpes simplex 2
genital herpes
have intranuclear acidophilic Cowdry type A inclusions

Question 36

HHV 3

Answer 36

Varicella-zoster virus
Chicken pox
Usually transmitted by saliva
Shingles: reactivation of latent infection, trigeminal n. distribution is common

Question 37

HHV 4

Answer 37

Epstein-Barr virus (EBV)
attaches to CD21 = complement receptor 2 = EBV receptor
mono
atypical activated T-lymphocytes (Downey cells)
Hodgkin lymphoma, Burkitt lymphoma, CNS lymphomas, nasopharyngeal carcinoma
Dx: heterophile Abs (Monospot)

Question 38

HHV 5

Answer 38

cytomegalovirus (CMV)
owl-eye inclusion
infects monocytes/precursors
mono
congenital CMV infection
transplacental, neonatal, perinatal, and salivary transmission

Question 39

HHV 8

Answer 39

Kaposi sarcoma-associated herpesvirus