Control of Viral Population

Question 1

ways to control viral population

Answer 1

• Quarantine
• Good hygiene
• Changes in lifestyle
• Elimination of a vector
• Immunize the population
• Development and implementation of antivirals

Question 2

ways to control outbreak

Answer 2

ID source/reservoir, clean-up, quarantine, immunization, etc.

Question 3

Universal precautions when handling blood

Answer 3

assume contamination

Question 4

Essential in hospital / health care settings in order to control viral disease

Answer 4

Limit contact, immunize health care workers, improve hygiene

Question 5

disinfection for virus

Answer 5

70% ethanol, 15% chlorine bleach, autoclaving

Question 6

is education (public, research) important for viral control

Answer 6

yeah

Question 7

vaccines for virus

Answer 7

1) Inactivated (killed)
2) Live-attenuated
3) Subunit
4) DNA

Question 8

difference between prophylactic and therapeutic

Answer 8

prophylactic - used to prevent contracting infection

therapeutic - used to treat once infection has been contracted

Question 9

ways to prevent or treat viral populations

Answer 9

vaccines, antivirals, stimulate host innate immune system

Question 10

ways to stimulate host innate immune system

Answer 10

– Interferon (induces synthesis of cellular proteins capable of inhibiting translation or transcription)
– Activate NK kills (agents that bind to toll-like receptors)
– Antibodies (natural or passive immunization)

Question 11

what qualities make a vaccine good?

Answer 11

– Cheap (for majority of vaccines, new vaccines usually much more expensive)
– Used before discovery of viruses
– Result in decline of illness and death (polio, MMR, etc.) - humans and animals
– Eradication (smallpox)

Question 12

what are live attenuated vaccines

Answer 12

LIVE virus particles that grow in the vaccine recipient but do not cause disease because the vaccine has been altered (mutated) to a non pathogenic form

Question 13

examples of infections treated with live attenuated vaccines

Answer 13

Polio (Sabin), MMR, Yellow fever, Rotavirus, Varicella

Question 14

what are inactivated vaccines

Answer 14

Preparations of the normal (wild type) infectious, pathogenic virus then rendered non-pathogenic usually by chemical treatment such as with formalin that cross- links viral proteins

Question 15

example of infections treated with inactivated vaccines

Answer 15

Polio (Salk), Influenza, HepA

Question 16

what are subunit viral vaccines

Answer 16

• Purified virus components
• Recombinant proteins that self-assemble
into Virus Like Particles (VLPs) and they help host form resistance

Question 17

example of viruses treated with subunit

Answer 17

HepB, Quadrivalent HPV

Question 18

what type of vaccine is gardasil

Answer 18

subunit

Question 19

how does HPV vaccine work

Answer 19

– Recombinant L1 proteins that self-assemble into VLPs and is given before the onset of sexual activity
– ~100% protection from infection with vaccine HPV types
– Potential to prevent ~70% of cervical cancers,
~90% of genital warts

Question 20

what is a DNA viral vaccine

Answer 20

• Usually harmless viruses into which a gene for a (supposedly) protective antigen has been spliced
• Protective antigen is then made in the vaccine recipient to elicit an immune response

Question 21

how do antivirals work

Answer 21

they interfere with virus specific functions and interfere with cellular functions (preferably virus infected)

Question 22

properties of antivirals

Answer 22

water soluble, taken up by cells, stable

Question 23

what are antivirals not?

Answer 23

– toxic
– carcinogenic 
– allergenic
– mutagenic
– teratogenic

Question 24

what properties make a good medicine

Answer 24

• activity
• solubility
• oral bioavailability
• half life
• metabolic profile/toxicity

Question 25

viruses treatable with antivirals

Answer 25

* Herpes simplex virus * Varicella-zostervirus * Cytomegalovirus * Human immunodeficiency virus * Influenza A and B viruses * Respiratory syncytial virus * Hepatitis B and C viruses * Papillomavirus * Picornavirus

Question 26

goal of antivirals

Answer 26

virion disruption or inhibition of life cycle

Question 27

how do antivirals block attachment hence blocking subsequent stages

Answer 27

– tends to be virus specific, more for prophylaxis | – neutralizing antibodies bind viral receptors 􏰂 prevent attachment of the virus to the host cell

Question 28

how do antivirals block penetration

Answer 28

fusion inhibitors

Question 29

how do antivirals block uncoating

Answer 29

– amantadine

Question 30

how do antivirals block replication

Answer 30

– Nucleoside analogues: incorporated into viral genomes | – Get chain termination: analogues lack hydroxyl groups for linking of backbone

Question 31

example of an antiviral that blocks replication

Answer 31

acyclovir

Question 32

what is acyclovir used to treat

Answer 32

HHV I and HHV II infections

Question 33

how does acyclovir work

Answer 33

it is a guanine analogue that uses viral thymidine kinase --> monophosphate (using host cell TK) --> diphosphate (using host cell TK) --> triphosphate acyclovir triphosphate blocks DNA synthesis by chain termination which it does by inhibiting the function of viral DNA polymerase

Question 34

nucleoside inhibitors of reverse transcriptase

Answer 34

Azidothymidine (AZT), ddI (nucleoside polymerase inhibitors)

Question 35

what are non-nucleoside polymerase inhibitor example and how does it work?

Answer 35

Nevirapine - bind to various sites on enzyme

Question 36

antiviral that blocks assembly and release

Answer 36

Protease inhibitors (Saquinavir, etc.)

Question 37

how does Saquinavir (protease inhibitor) work

Answer 37

– Block cleavage of polyproteins – HIV is dependent on proteolytic enzyme for full infectivity – Drug-resistant strains > protease mutations

Question 38

what causes resistance to antivirals

Answer 38

``` • Targeted enzyme changes • Mutations, deletions, substitutions • Replication rate – type of NA figures heavily here • Preventative measures against resistance – Rationale behind antiviral “cocktails” ```

Question 39

examples of immunomodulators

Answer 39

• Interferons – IFN-α: active against many viral infections • Imiquimod – Toll-like receptor ligand, stimulates innate responses to attack the virus infection (HPV)

Question 40

examples of viruses that use interferons

Answer 40

Hep A, B, and C, HSV, HPV, and rhinovirus