Microbiology 15: Antiviral Therapy

Question 1

What disease does EBV cause ?

Answer 1

Infective mononucleosis

Question 2

Where does Varicella Zoster Virus lay dormant in the body?

Answer 2

Dorsal root ganglia

Question 3

What is a complication of Chickenpox in adults?

Answer 3

Varicella pneumonitis

Question 4

What is a complication of shingles in immunocompetent adults ?

What complication in immunocompromised

Answer 4

Post-herpetic neuralgia - dermatomal distribution occurs

experience multi-dermatomal or disseminated infection

Question 5

Which medication is 1st line for treatment of HSV and VZV ?

Answer 5

Aciclovir

Question 6

What type of anti viral is acyclovir ?

Answer 6

Nucleoside (guanosine) analogue

They get incorporated into growing chain of DNA causing it to terminate

Question 7

Give 2 reasons why aciclovir has reduced toxicity to normal cells compared to cells infected with a virus?

Answer 7

Aciclovir requires activation by viral thymidine kinase (found in cells infected by viruses)

Aciclovir has a higher affinity for Herpes virus DNA polymerase compared to human DNA polymerase

Question 8

Which medical emergency is caused by HSV ?

Tx

Answer 8

HSV encephalitis - get fever, confusion, altered consciousness +/- seizures

start empiric treatment IMMEDIATELY with IV Aciclovir 10mg/kg TDS WITHOUT waiting for test results

Question 9

What is the characteristic histological appearance of CMV infection ?

Answer 9

Owl’s eye inclusions

Question 10

Which virus are immunocompromised patients particularly at risk of compared to immunocompetent people ?

Answer 10

CMV (since opportunisitc infection) - lies latent in monocytes and dendritic cells

Question 11

In which cells does CMV tend to lie dormant ? (2)

Answer 11

Monocytes
Dendritic cells

Question 12

What anti viral treatments are used to treat CMV infection ?

Answer 12

• 1st: Ganciclovir/valganciclovir
• 2nd: Foscarnet
• 3rd: Cidofovir

Question 13

Which disease can EBV cause in immunocompromised patients ?

How do you treat?

Answer 13

• PTLD - post transplant lymphoproliferative disease
• This predisposes to lymphoma
• The EBV keeps dividing unless kept in check by the immune system
• This causes polyclonal activation of B cells

Tx: immunosuppression + rituximab

Question 14

What does PTLD predispose to ?

Answer 14

B cell lymphoma

Question 15

What is the treatment for PTLD ?

Answer 15

Rituximab - monoclonal antibody against CD20 B cell surface marker

Question 16

What are the 2 main surface proteins on influenza virus ?

Answer 16

• HA- haemaglutinin
• NA- Neuraminidase

These allows viruses to bind and enter the target cells

Question 17

Which disease is commonly caused by RSV ?

Answer 17

Bronchiolitis

Question 18

Who should palivizumab be given to prophylactically ?

Answer 18

• High risk infants (preterm, heart or lung disease, SCID) in the winter months
• Prevents severe LRTI from RSV

Question 19

Which 2 diseases does BK virus cause in immunocompromised patients?

Answer 19

Haemorrhagic cystitis in bone marrow transplant patients

BK nephritis in renal transplant patients

Question 20

Which immunomodulatory therapy is used to treat hepatitis B ?

Answer 20

Interferon Alpha

Question 21

Which antiviral drug is used to treat and prevent Influenza In the elderly?

What is MoA?

Answer 21

Oseltamivir (Tamiflu)

Directly inhibits the influenza neuraminidase (NA)

Question 22

Which antiviral can be used in aerosol form to prevent RSV infection in children with heart and lung disease ?

Answer 22

Ribavirin (guanosine analogue)

Question 23

Which antiviral is the drug of choice for CMV infection ?

Answer 23

Ganciclovir

Question 24

What is the prodrug of aciclovir that can be used in VZV infection ?

Answer 24

Valaciclovir (but aciclovir more common)

Question 25

Which antiviral drug is used to treat severe resistant herpes infection ?

Answer 25

Foscarnet

Question 26

Which HIV drug works by inhibiting reverse transcriptase by acting as a guanine analogue?

Answer 26

Zidovudine

Question 27

treatment for HSV meningitis

Answer 27

usually self limiting IV aciclovir 2-3 days, then switch to oral for 10 days valaciclovir alternative in immunocompetent to avoid cannulation

Question 28

describe how viruses gain entry into cells

Answer 28

* HA mediated virus binding and entry into target cell * NA allows the release of progeny virus particles from the host cell * NA is the target for current anti-influenza drugs

Question 29

adenovirus treatment

Answer 29

cidofovir IV IVIR brindcidofovir PO

Question 30

A 42-year-old lady is admitted with a 2 day history of fever and confusion and presents with new onset seizures. What antiviral medication should she receive as soon as possible?

Answer 30

IV aciclovir HSV encephalitis is a medical emergency and treatment is with a 2-3 week course of high dose IV aciclovir

Question 31

Transplant patients with CMV pneumonitis - what drug do you give + which adjunt?

Answer 31

**Ganciclovir + IVIg**

Question 32

New drug for CMV (2)

Answer 32

Maribavir Letermovir

Question 33

BK Virus is part of which family of viruses

Answer 33

polyomavirus

Question 34

Where does BK virus stay latent (2)

Answer 34

lifelong carriage in kidneys and urinary tract

Question 35

Tx of BK Haemorrhagic Cystitis Tx of BK nephropathy

Answer 35

* **IV Cidofovir** (+ probenecid) if significant morbidity - NB this is nephrotoxic * **Intravesical cidofovir** (5mg/kg/week)- this is an option of there is nephrotoxicity * normal human IVIg

Question 36

Which group does adenovirus present in? Tx (2)

Answer 36

paediatric transplant recipients Tx: Cidofovir + IVIg

Question 37

2 main Tx of hep B

Answer 37

* Main: IFN-alpha * Other: nucleotide analgoue (tenefovir)

Question 38

2 types of antiviral resistance assays (investigative procedure)

Answer 38

* Genotypic: sequencing the viral nucleic acids and identifying mutations known to confer resistance * Phenotypic: consists of a cell culture

Question 39

HSV drug resistance mechanism How to do Ix Tx (2)

Answer 39

Mutations are usually in viral thymidine kinase - Almost exclusively seen in immunocompromised patients Plaque Reduction assay Foscarnet and Cidofovir

Question 41

Mechanism of CMV resistance Tx (2)

Answer 41

In protein kinase gene (UL97) Foscarnet or Cidofovir

Question 42

Tx for EBV driven PTLD

Answer 42

Rituximab (anti-CD20)