Respiratory viruses

Question 1

Where do RNA and DNA viruses replicate

Answer 1

RNA: cytoplasm
- 1 exception: Influenza rep. in Nucleus

DNA: Nucleus
- 1 exception: Poxvirus rep in cytoplasm.

Question 2

Enveloped tend to be transmitted how?

Answer 2

Mucosal

- Not F-O cant make it past stomach acid

Question 3

Killed vaccine (most common influenza vaccine) - shot in arm

Attenuated vaccine (oral)

Answer 3

generate only Ab response

Generate Ab and T cell response

Question 4

Why do we need a new Influenza vaccine every year?

Answer 4

Antigenic drift: in HA and NA occur via point mut in gene –> aa seq changes that alter Ag sites and host’s immune system no longer recognizes it.

Need to match the circulating strain!
- Protect against Bivalent, A+B (not C)

Question 5

Influenza tx

Answer 5

1. Neuraminidase inhibitors
   - Zanamivir
   - osteltamivir
   - peramivir
2. Adamantane agents
   - amantadine
   - rimantadine

Question 6

Viruses that infect the URT

Answer 6

1. Rhinovirus
2. Parainfluenza virus
3. RSV
4. Influenza virus
5. Adenovirus
6. HSV
7. EBV

Question 7

Viruses that infect the LRT

Answer 7

1. Parainfluenza virus (diff strains)
2. RSV
3. Influenza virus
4. Adenovirus (diff strains)

Question 8

Temp diff between URT and LRT

Answer 8

URT: 33C
LRT: 37C

Question 9

Which viruses have this pattern of infxn:

Acute Infxn w/ rep. confined to respiratory mucosal surfaces

Answer 9

1. Paramyxovirus
   - Parainfluenza 1,2,3
   - RSV
2. Orthomyxovirus
   - Influenza A,B,C
3. Coronavirus
4. Picornavirus
   - rhinovirus

Question 10

Which viruses have this pattern of infxn:

Persistent replication on respiratory mucosal surfaces

Answer 10

1. EBV
2. Adenovirus
3. Papillomavirus

Question 11

Which viruses have this pattern of infxn:

Systemic replication AFTER primary replication on resp. mucosal surfaces

Answer 11

1. Paramyxovirus
   - mumps
   - measles
2. VZV
3. HHV6
4. CMV
5. Rubella
6. Bunyaviruses
7. Arenavirus
8. Parvovirus
9. Picornavirus
10. Poxvirus
11. Reovirus

Question 12

Most common viral causes of common cold

Answer 12

1. Rhinovirus
2. Coronavirus
3. Influenza virus

Question 13

Which one is segmented, Orthomyxoviridae or paramyxoviridae?

WHich one is enveloped?

Answer 13

Orthomyxoviridae
Segmented (-) sense RNA

Paramyxoviridae
Nonsegmented (-) sense RNA

• BOth are enveloped

Question 14

Influenza virus envelope carries what?

Answer 14

2 types of protruding spikes

1. NA
   - 9 antigenic types
2. HA
   - 13 major antigenic types

variations –> influenza subtypes (H1N1, H1N2 ect)

Question 15

Influenza A, B, C, which one infects mainly humans?

Answer 15

B, C

A- any

vaccines are against A and B not C

Question 16

Antigenic shift occurs in which influenza strain?

Answer 16

A -mAjor change in HA and NA
See shift and drift in A, only drift in B

• Ag appear unlike those of viruses immediately preceeding them
• emergence of new antigenic variants (due to genetic reassortment from other animal species - easier if virus is segmented)

Question 17

THe flu vaccine does NOT protect against which type influenza?

Answer 17

Type C

- cause mild respiratory illness not thought to cause epidemics