Lec 21 - Respiratory viral infections 1: IV and RSV

Question 1

What common complication arises from viral infection of the respiratory tract?

Answer 1

• Viral infection damages epithelia
• Secondary bacterial infection results

Question 2

What are the 2 types of transmission and how are they different?

Answer 2

1. Short range transmission = droplets or aerosols by direct or indirect contact
2. Long range transmission = aerosols by indirect contact

Question 3

What are fomites?

Answer 3

Objects/materials carrying infection eg clothes, furniture

Question 4

What is the classification and transmission of Rhinovirus?

Answer 4

• Enterovirus of Picornaviridae; group 4 (+) ssRNA non-enveloped
• Transmission = droplets and fomites

Question 5

What are the human species of Rhinovirus and what cell surface molecule do they bind?

Answer 5

• RV-A, RV-B, RV-C species
• ICAM-1 used by A and B

Question 6

Where does Rhinovirus replicate and what are the symptoms? Describe the allergic immune response.

Answer 6

• Replication = 33C in nasopharynx’s mucosa; LRT infection in babies/children
• Sinusitis, bronchitis, otitis, exacerbated asthma and atopic
• Atopic = Th2 production increases ICAM-1 on bronchoepithelial cells with reduce antiviral cytokine production = severe infection

Question 7

What is the classification and location of replication of RSV?

Answer 7

• Orthopneumovirus of Pneumoviridae; group 5 (-) ssRNA filamentous; glycoproteins
• Infects and reps in nasopharynx then spreads to LRT

Question 8

Describe the pathology of RSV infection and how babies can be protected naturally.

Answer 8

• Increased mucus and inflammation = bronchiolitis and airway narrowing
• Passive maternal neutralising antibodies in 3rd trimester
• No long term immunity

Question 9

How does RSV evade immunity?

Answer 9

• Glycosylation and structural variability = escape neutralising antibodies
• G protein binds anti-RSV antibodies and inhibits type 1 IFN production by TLR pathway

Question 10

What is the classification and location of infection of human metapneumovirus (HPMV)?

Answer 10

• Paramyxovirus; enveloped group 5 (-) ssRNA; glycoproteins
• URT and LRT infections in all ages

Question 11

What are the symptoms and complications of human metapneumovirus? How does it modulate the immune response?

Answer 11

• Symptoms = cough, fever, nasal congestion, shortness of breath, bronchitis, pneumonia, exacerbated COPD, bronchiolitis
• Complications = encephalitis, neurological
• Modulates = infected DC factors impair CD69 upregulation which inhibits T cell priming

Question 12

What is the classification of Rubella/German measles virus?

Answer 12

• Rubivirus of metonaviridae; enveloped group 4 (+) ssRNA

Question 13

What are the symptoms and complications of Rubella/German measles virus?

Answer 13

• Symptoms = mild illness, rash, systemic infection
• Complications = miscarriage, congenital rubella syndrome = blueberry muffin skin lesions, cataracts, deafness, blindness

Question 14

Why are there different vaccine responses for Rubella/German measles virus?

Answer 14

High and low vaccine responders from SNPs in innate immune receptors

Question 15

What is the classification and transmission of Measles virus?

Answer 15

• Morbillivirus of paramyyxoviridae; group 5 (-) ssRNA
• Transmission = airborne by aerosols and droplets, or direct contact
• Transmission = 4 days before rash to 4 days after rash

Question 16

What are the symptoms and complications of Measles virus?

Answer 16

• Symptoms = coughing, sneezing, systemic
• Complications = otitis media, croup, pneumonia, encephalitis, subacute sclerosing panencephalitis

Question 17

How does Measles virus infection affect the immune system?

Answer 17

Immune amnesia = memory B and T cells and naïve B cells destroyed to clear infection

Question 18

What is the classification and transmission of Mumps virus

Answer 18

• Orthorubulavirus of paramyxolviridae; enveloped group 5 (-) ssRNA
• Transmission = inhalation of aerosols

Question 19

Describe the pathology of Mumps virus and list the symptoms and complications involved.

Answer 19

• Infects activated T cells in RT then disseminates to salivary glands, testes and CNS
• Symptoms = swollen parotid gland, usual flu-like symptoms
• Complications = meningitis, encephalitis, deafness, pancreatitis

Question 20

What is the classification and and pathology of parainfluenza virus?

Answer 20

• Resipovirus of paramyxovirus; enveloped group 5 (-) ssRNA
• HA binds sialic acid on respiratory mucosa’s neuraminidase

Question 21

What are the symptoms of Parainfluenza virus in the typical illness vs the severe illness?

Answer 21

• URT = fever, rhinitis, cough, sneezing, laryngitis
• Severe = croup, bronchitis, pneumonia

Question 22

What is the classification and transmission of Adenovirus?

Answer 22

• Adenoviridae; non-enveloped group 1 dsDNA
• Droplets, faecal matter, fomites, close contact
• URT and LRT then digestive and ocular tracts

Question 23

List the symptoms and complications of Adenovirus.

Answer 23

• Symptoms = erythematous rash, pharyngitis, keratoconjunctivitis
• Complications = hepatitis, cystitis, colitis, meningoencephalitis, bronchopneumonia

Question 24

How does Adenovirus affect the immune response?

Answer 24

Suppresses type 1 IFN and IFN-y

Question 25

Who is JC virus named after?

Answer 25

John Cunningham

Question 26

Describe the initial infection and reactivation of JC virus.

Answer 26

• Acquired by RT then disseminates to kidneys
• Persistent latent infection in lungs and brain causing progressive multifocal leukoencephalopathy