DNA Viruses

Question 2

What are the 3 types of viral infections at the cellular level?

Answer 2

Lytic
Nonlytic
Oncogenic

Question 3

What characterizes lytic viral infections?

Answer 3

Virus accumulates inside cell —> ↑ osmotic pressure —> cell bursting

Question 4

What characterizes nonlytic viral infections?

Answer 4

Persistent, slow release of virus from cell via exocytosis or membrane budding
Latent infection via virus regulating its gene expression to conserve its genome

Question 5

What characterizes oncogenic viral infections?

Answer 5

DNA and retroviruses that establish a persistent infection by stimulating uncontrolled cell growth

Question 6

What is the name for the process in which oncogenic viruses stimulate uncontrolled cell growth by establishing a persistent infection?

Answer 6

Transformation or immortalization

Question 7

How can oncogenic viruses stimulate uncontrolled cell growth? (4)

Answer 7

Activating growth factors
Removing braking mechanisms that limit cell growth
Preventing apoptosis
Encoding oncogenes (retroviruses)

Question 8

What are the S&S of primary hepatitis B infection?

Answer 8

Jaundice
Light-coloured stool
Fever
Fatigue for weeks/months
Loss of appetite, nausea, vomiting

Question 9

What are the S&S of secondary hepatitis B infection?

Answer 9

Positive test for 6 months
Persistent elevated liver enzymes (ALT/AST)
Liver fibrosis
Liver Cirrhosis
Hepatocellular carcinoma

Question 10

What is the prevention for Hep B?

Answer 10

Vaccine available, but no use once infected
Transmitted via blood and sexual contact

Question 11

What type of anti-viral is used for the treatment of Hep B?

Answer 11

Nucleoside analogue reverse transcriptase inhibitors

Question 12

How are HHV transmitted?

Answer 12

Usually via active lesion, but HHV-2 can be shed while asymptomatic
Close bodily contact at mucous membranes

Question 13

What causes the lesions associated with HHV?

Answer 13

Inflammation and cell death at site of infection

Question 14

What causes cold sores?

Answer 14

HHV-1
Transmitted via casual contact

Question 15

What causes genital herpes?

Answer 15

HHV-2
Transmitted via sexual activity

Question 16

This class of antiviral helps manage several viruses including HHV, VZV, and CMV

Answer 16

Nucleoside analogue inhibitors

Question 17

How do nucleoside analogue inhibitors work?

Answer 17

False nucleotides that interfere with viral replication
Addition of false nucleotide —> chain termination —> virus unable to make new copies of itself
In retroviruses (ex. HIV) inhibits reverse transcriptase from converting viral RNA into DNA

Question 18

VZV is highly infectious and seen most commonly in children. What is the severity of this virus like in adults vs children?

Answer 18

More severe in adults than in children

Question 19

How long after infection do skin lesion appear for VZV?

Answer 19

2-3 wks

Question 20

How is VZV transmitted?

Answer 20

Resp tract or eyes

Question 21

What is herpes zoster/shingles?

Answer 21

Reactivation of VZV, typically in adulthood when the immune system is vulnerable

Question 22

Shingles is a reactivation of VZV. How does its presentation differ from VZV?

Answer 22

VZV is non-localized and tends to be diffuse
Shingles presents as a rash localized over a dermatome (area of skin supplied by a single spinal nerve)
Shingles is a reactivation of VZV; the initial infection moves up a spinal nerves and lies dormant in dorsal root ganglia
Reactivation —> virus moving down dermatome

Question 23

How is EBV transmitted?

Answer 23

Saliva

Question 24

What types of cells are affected by EBV and how are they affected?

Answer 24

EBV invases B lymphocytes, becomes latent in them and immortalizes them by suppressing apoptosis
Can cause B cell lymphoma in rare cases

Question 25

What group of people are susceptible to extreme disease r/t EBV?

Answer 25

Those with T cell deficiencies This is bc infected B cells aren’t removed by cytotoxic T cells —> virus proliferation

Question 26

What virus causes “mono”?

Answer 26

EBV

Question 27

How is CMV transmitted?

Answer 27

Sexual contact In utero exposure Vaginal birth Blood transfusions Organ transplants

Question 28

What are the complications associated with CMV?

Answer 28

Birth defects that can result in death IC pts can develop pneumonia, blindness, or CMV mononucleosis (similar to infectious mononucleosis)

Question 29

How is CMV diagnosed?

Answer 29

- Detection of abnormally enlarged cell - CMV viral load

Question 30

How is CMV treated?

Answer 30

Ganiciclovir or valganciclovir Fomiversen for CMV eye infections

Question 31

What virus causes “slapped cheek disease”?

Answer 31

Parvovirus

Question 32

What is the prevention for parvovirus?

Answer 32

No treatment, no vaccine :(

Question 33

What are important consideration for parvovirus risk to pregnant individuals?

Answer 33

Spontaneous abortion Congenital anomalies Hydrops fetalis (fetal anemia, fetal viral myocarditis, impaired hepatic function) B19-Specific IgG and IgM can be given to this population

Question 34

What is the treatment for HPV?

Answer 34

No viral tx Med for symptoms: podophylin, imiquimod, podofilox Intervention for symptoms: freezing, electrical burn, laser, direct interferon injection, removal

Question 35

What is the main concern with HPV infection?

Answer 35

Cancer

Question 36

This is one of the causative agents of the common cold and is spread via resp droplets

Answer 36

Adenovirus

Question 37

Infection of the conjunctiva with this virus can cause pinkeye

Answer 37

Adenovirus