Virology

Question 1

Most common cause of encephalitis immunocompetent

Answer 1

HSV

diagnosis CSF for PCR

Question 2

Most common cause of meningitis immunocompetent

Answer 2

Enterovirus (cocksackie A&B, echovirus, poliovirus)

Diagnosis CSF for PCR

Question 3

most common cause of URI immunocompetenet

Answer 3

Influenza
RSV
parainfluenza
metapneumovirus
rhinovirus
adenovirus
enterovirus
NP swab/aspirate for DFA, PCR and/or culture

Question 4

Most common cause viral pneumonia immunocompetent

Answer 4

Influenza

RSV

Question 5

most common cause gastroenteritis immunocompetenbt

Answer 5

norovirus
adenovirus
astrovirus
rotavirus
stool for PCR
rotavirus has antigen detection or PCR

Question 6

most common causes of mononucleosis immunocompetent

Answer 6

EBV (heterophile antibody test for screening)

CMV

Question 7

most common causes vesicular rash immunocompetent

Answer 7

oHerpes simplex virus (HSV-1, HSV-2)
oVaricella zoster virus
Diagnosis: aspirate or swab of vesicle for PCR, antigen detection, and/or culture

Question 8

most common cause genital ulcers immunocompetent

Answer 8

Herpes simplex virus (HSV-1, HSV-2)

Diagnosis: swab of ulcer for PCR, antigen detection, and/or culture

Question 9

Most common cause of anemia immunocompetent

Answer 9

Parvovirus B19

Diagnosis: blood for serology (IgM, IgG) or PCR

Question 10

PMK/RHMK, RK, HNK

Answer 10

Primary Epithelial Cell Line
Diploid, 1-2 passages
Further passage results in decreased receptivity to viral infection
PMK/RHMK (monkey kidney), RK (rabbit kidney), HNK (neonatal kidney)

Question 11

HDF, MRC-5, WI-38

Answer 11

Fibroblast Cell Line
Diploid, < 50-70 passages
HDF (human diploid fibroblast), MRC-5 (lung fibroblasts), WI-38

Question 12

A549, HEP-2

Answer 12

Transformed Cell Line
Heteroploid, continuous passages
Remains sensitive to viral infection indefinitely
A549 (human lung adenocarcinoma, left), HEp-2 (human epidermoid carcinoma, right)

Question 13

Describe conventional tube culture

Answer 13

Cells in monolayer on sides of roller tube are inoculated with specimen and incubated for 1-4 weeks depending on suspected virus. Culture is periodically inspected for CPE and virus can be determined by CPE, time to CPE, and cell line supporting growth.

Question 14

Describe shell vial culture

Answer 14

Uses a tube with a coverslip at the bottom, which has a monolayer of cells. The infected monolayer is stained for viral antigens produced soon after infection and before CPE. Detection within 1-2 days by DFA. Disadvantage is only one type of virus can be detected per shell vial.

Question 15

HBV acute infection serology

Answer 15

Pos HBsAg and anti-HBc IgM

Also have HBeAg and HBV DNA

Question 16

HBV past infection serology

Answer 16

antit-HBs and anti-HBc IgG

Question 17

HBV immunization serology

Answer 17

anti-HBs only

Question 18

HBV chronic infection serology

Answer 18

HBsAg pos for > 6 months

HBeAg and serum HBV DNA +/-

Question 19

EBV serologies

Answer 19

oHeterophile antibody: screening test, usually positive in acute infection
oAnti EA (early antigen): positive in acute infection
oIgM VCA (viral capsid antigen): positive, wanes 3 months after acute infection
oIgG VCA (viral capsid antigen): positive in acute infection and persists for life
oAnti EBNA (Epstein-Barr nuclear antigen): negative in acute infection; seen 6-12 weeks after symptoms begin