Enveloped Viruses: Day 3

Question 1

What are the two important forms of enveloped DNA viruses?

Answer 1

Herpesvirus, Poxvirus,

Question 2

What characterizes herpesviruses structurally? life cycle wise?

Answer 2

caspid has a protein layer overlying it called the tegument (this is underneath the envelope). these are released post infection: disarms cellular defenses.

characterized by a prolonged period of latency with occasional reactivation that is often triggered by stress

Question 3

What type of virus is HSV-1 and HSV-2? What is their caspid symmetry, nucleic acid type, and site of replication?

Answer 3

herpes virus, enveloped DNA virus

linear dsDNA
isosahedral

Question 4

In what type of cells do HSV do lytic infections? What about latent? What is different about the RNA expressed in these two cell types?

Answer 4

epithelial cells: lytic
have 84 genes, including DNA polymerase

some neurons: latent
only one RNA is expressed (LAT– Latency Associated Transcript)

Under stress conditions: reactivation in neurons leads to reinitiation of lytic cycle

Question 5

Does latent herpes respond to drugs or immune response?

Answer 5

because only LAT is expressed: the enzymes that drugs target aren’t expressed, and virus can’t be recognized.

Question 6

Regarding intraneuronal transport of a virus:

What is retrograde transport?

What is anterograde transport?

Answer 6

Retrogade: infection and replication at the portal of entry. establishes latency.

Anterograde transport: transport to a site at or near the portal of entry: during reactivation

Question 7

How many herpesviruses are there?

Answer 7

HSV 1-8

Question 8

HSV-1 and HSV-2 establish latency where?

Answer 8

sensory neurons

Question 9

How does viral adult encephalitis occur?

Answer 9

HSV 1 during reactivation somehow crosses into CNS

Question 10

HSV transmission, initial target, primary viremia target

Answer 10

transmitted through direct contact, initial to sensory neurons, primary (rare) brain

Question 11

HSV 1-2 caspid symmetry, nucleic acid, site of replication

Answer 11

yes, isosahedral, linear dsDNA, nucleus

Question 12

VZV caspid symmetry, nucleic acid, site of replication

Answer 12

isosahedral, linear dsDNA, nucleus

Question 13

VZV transmission, initial target, primary viremia target, secondary viremia target,

Answer 13

aerosol, respiratory tract i sensory neurons,

primary : viral replication happens in the liver and spleen;

secondary: mononucleated cells transport virus to skin and mucus membranes, skin and mucus membranes

Question 14

what is shingles?

Answer 14

an acute, painful inflammation of the nerve ganglia, with a skin eruption often forming a girdle around the middle of the body. It is caused by VZV

Question 15

cytomegalovirus: caspid symmetry, nucleic acid, site of replication

Answer 15

isosahedral, linear dsDNA, nucleus

Question 16

cytomegalovirus transmission, initial target, primary and seocndary viremia target

Answer 16

direct contact, monocytes (often in salivary glands), n/a for primary and secondary

Question 17

cytomegalovirus: what percent transmits to fetus from mother with infection?

Answer 17

40%. this is unusual, most can’t transfer through placenta

Question 18

what diseases CMV cause?

Answer 18

petechiaie (purple spots), liver disease, neurologic deficits

Question 19

what disease causes mono?

Answer 19

EBV: epstei-barr virus

Question 20

EBV caspid symmetry, nucleic acid, site of replication

Answer 20

isosahedral, linear dsDNA, nucleus

Question 21

EBV transmission, initial target, primary viremia target, secondary viremia target

Answer 21

direct contact with saliva, sexual; initial target: oropharyngeal cells, salivary cells, B lymphocytes;

primary viremia target n/a; secondary viremia target n/a

Question 22

If you do a Wright stain on EBV patients, what should you see?

Answer 22

atypical lymphocytes: cytotoxic suppressor T lymphocytes that are killing the infected B cells

Question 23

What is the heterophile antibody test?

Answer 23

it’s how you can tell early (3-7 wk) diagnosis of EBV

non-specific gluttination of non-human red blood cells ?

Question 24

why does the football player with mono get told to calm down and stop playing?

Answer 24

splenomegaly and hepatomegaly during the 5.5 - 10.5 week period

Question 25

when does HHV6 happen (agewise) most often?

Answer 25

primary infetion common first year of life, peaks in second six months

fever and then transient rash (roseola) -> 20% ED visits of these infants 6- 18 mo

most adults are HHV-6 positive

Question 26

HHV 8 COMMON NAME? what was a disease is it associated with?

Answer 26

Kaposi’s sarcoma. major associated with AIDS. common in HIV+ men MSM

Question 27

how do you treat HHV8?

Answer 27

pretumor: give some gancyclovir, but isn’t super effective. post tumor, surgery, irratiation, chemotherapy, try to bring back immunosuppression (HAART for HIV patinets)

Question 28

poxvirus: nucleic acid, caspid symmetry, site of replication

Answer 28

complex, linear dsDNA, cytoplasm

Question 29

poxvirus transmission

Answer 29

airborne