Mirco: Virology

Question 1

Herpes family
latent where?
transmission

Answer 1

ds DNA viruses, envelope ("fried egg")
-direct contact transmission (saliva, sexual)
-some via transfusion/transplant: CMV, EBV, HHV6, HHV8
-latent in:
DRG: VZV, HSV1, HSV2
monocytes, macro, CD34+ cells: CMV, HHV6
CD4+: HHV7
memory B cells: EBV
B cells: HHV8

Question 2

1ry vs latent vs reaction disease

Answer 2

-

Question 3

HSV?

Answer 3

• herpes - oral/genital . sores
• 1-3wk incubation time
• reactivation: sunlight, fever, trauma, menstruation, stress
• fluid culture, EM, immunofluorescence, PCR, no IGM test
  tx: antivirals

Question 4

VZV?

Answer 4

-herpes
-most contagious
-airborne transmission
>chickenpox
>shingles
>congenital varicella
dx: Igg and igM; EM, immunofluorescence
tx: acyclovir if severe otherwise ok
IZIG - given 96 post exposure
vaccines: chickenpox and shingles

Question 5

HHV6

Answer 5

-herpes
>ROSEOLA INFANTUM - fever, rash
-asx
-treat symptoms
dx: clinical, serology available but not routine

Question 6

EBV

Answer 6

-herpes
>infectious mono
-longer incubation : wks-months
-associated with Burkit’s lymphoma and nasopharyngeal carcinoma
dx: no routine culture; PCR for monitoring not dx
-seorlogy for Ab
tx: no antivirals, protect spleen, no vaccine

Question 7

CMV?

Answer 7

-cytomegalovirus (herpes)
-1-3 wk incubation
-mono-like symptoms
>intrauterine congenital infections
dx: culture, EM, immunofluorescence, serology, PCR
-no tx for competent pts.
immuno comp = Ganciclovir, foscarnet

Question 8

HHV8

what is is associated witth

Answer 8

herpes
->kaposi’s sarcoma
>febrile exanthem, mono-like, castleman’s disease, lymphoma
*treat with antiretroviral instead of antiherpes

Question 9

HIV

Answer 9

• RNA retrovirus
• from chimps we ate
• Typical course: 1ry infection > quick drop in CD4 T up to 6 wks > lymphocyte goes up around 6 wks , takes viral load down then drops and and level out > virus increase > CD4 decrease
• 12 hr lifecycle
• mortality in 5 yrs

Question 10

AIDS def

Answer 10

*HIV + opportunisitic infections (list of AIDS defining illnesses) or CD4 < 200 (viral loud x cd4 count)
>common infections:
-pneumonias
-TB
>tumours: cervical cancer (HPV), kaposi (HHV8), lymphoma (EBV)
>wasting, neuropathy, spinal cord, dementia

Question 11

HIV binding?

Answer 11

-gp120 receptor
NEED co-receptors: CCR5 or CXCR4 and CD4 receptor
-normal recetors for cytokines: SDF-1 and MIP / RANTES

Question 12

What happens bt immune activation and HIV

Answer 12

> HIV replication!

• proinflammatory cytokines (IL1, IL6, TNF a) > NFkappa b > transcription
• replicates a lot a day! > mutation and variance every day! hard for drug targets

Question 13

How does HIV cause immune suppression?

Answer 13

• decrease CD4T > induce apoptosis

- decrease fnc: doesn’t proliferate and doesn’t secrete IL2

Question 14

Dx of HIV?

Answer 14

• culture/isolate virus from nodes: $, labour
• PCR of plasma: $, fp
• RNA in cells: fp
• p24 antigen (virus protein) assay - only works if very high (
• detecting of Ab (last forever): ELISA

-early: RNA dectection; p24 within 2 wks; Ab 4-6wks

Question 15

How does HIV ELISA work?

Answer 15

• sensitivity: 99.5%. 1-2% false positive
  1. have HIV proteins on plate
  2. add pt serum. if Ab > bind proteins
  3. add conjugate
  4. add subtrate > reaction > colour detection

for better specificity: do a western blot > detect bound Ab to gp120, gp160, gp41 of virus envelope on gel

disad: acute HIV infection - takes 4-6wks before Ab shows up. repeat again in 1 month

Question 16

Antiviral Drugs: Classes and ex

anti-herpes

Answer 16

-Nucleoside analogues
(ACYCLOVIR: most herpes, disseminated shingles
VALACYCLOVIR,FAMCICLOVIR<shingles 
GANCICLOVIR - CMV)
-Nucleotide analougues (CIDOFOVIR)
-Pyrophsophate analogues (FOSCARNET)

Question 17

MofA for Nucleoside analogue

Answer 17

-antiviral
-similar to deoxynucleoside triphosphates (pentose sugar) except missing the OH at 3’ C
>chain termination
*used for