Antivirals

Question 1

Composition of viruses

Answer 1

Nucleic acid (DNA or RNA)
Protein (structural coat, non-structural enzymes)
\+/- Lipid envelope

Question 2

Acute virus infections

Answer 2

RNA viruses

Influenza, measles, mumps, Hep A

Question 3

Chronic virus infections

Answer 3

Usually DNA viruses
Can be latent with or without recurrences e.g. Herpes simplex, Cytomegalovirus
Can be persistent such as HIV, HTLV, Hep B, Hep C

Question 4

Non-vesicular viral rashes

Answer 4

Measles
Rubella
Parvovirus
Adenovirus
HHV6

Question 5

Vesicular viral rashes

Answer 5

Chickenpox (HHV3)
Herpes simplex (HHV1/2)
Enterovirus

Question 6

Respiratory viral infections

Answer 6

Influenza A/B
Respiratory Syncytial Virus
Parainfluenza virus
Human metapnuemovirus
Rhinovirus (cold)
Coronavirus (including SARS)

Question 7

Viral infections causing gastroenteritis

Answer 7

Rotavirus
Norovirus
Astrovirus
Sapovirus
Adenovirus (group F)

Question 8

Neurological viral disease

Answer 8

Encephalitis/meningitis!
HSV
Enteroviruses
Rabies
Japanese encephalitis virus
Nipah virus

Question 9

Blood-borne viruses

Answer 9

Hepatitis viruses (HBV, HCV
Retroviruses (HIV 1, 2 and HTLV 1, 2)

Question 10

When to use antivirals

Answer 10

Acute infections in general population where high risk of complications
Chronic infections e.g. HIV, HBV, HCV
Infections in the immunocompromised - post-transplant, immunosuppressed patients, those with primary immunodeficiencies

Question 11

Treatment of chickenpox and shingles

Answer 11

Treat with acicovir
Treat all adults with chickenpox
Treat shingles if:
 - The patient is >60
 - The eye is involved
 - They are immunocompromised

Question 12

Treatment of influenza

Answer 12

Neuraminidase inhibitors (oral oseltamivir and inhaled zanamavir)
Treat high risk patients:
- Chronic neurological, hepatic, renal, pulmonary and chronic cardiac disease
- Diabetes mellitus
- Severe immunosuppression
- Age over 65 years
- Pregnancy (including up to two weeks postpartum)
- Children under 6 months
- Morbid obesity (BMI over 40)

Question 13

Treatment of chronic virus infections

Answer 13

Usually lifelong antivirals
Antiviral toxicity and maintenance of good adherence can be issues
Need to avoid emergence of resistance
Exception is HCV which is caused by an RNA virus

Question 14

Virus replication

Answer 14

1: Virus attachment to cell via receptor
2: Cell entry
3: Virus uncoating
4: Early proteins produced - viral enzymes
5: Replication
6: Late transcription/translation - viral structural proteins
7: Virus assembly
8: Virus release and maturation

Question 15

HAART

Answer 15

Highly Active Antiretroviral Therapy
2 NRTIs + NNRTI or R NRTIs + boosted PI or integrase inhibitor
Often used in fixed drug combinations (more than one drug in pill)
Aim to switch off virus replication
Require life-long treatment

Question 16

Treatment of HCV

Answer 16

Directly acting antivirals
Generally use combination therapy (2 or 3 agents) for 8-12 weeks
Cure rate >95%
Different genotypes of HCV require different combinations although some antivirals work against all genotypes