Paramyxoviruses

Question 1

Comparison of Orthomyxovirues and Paramyxoviruses (8)

Answer 1

Viruses:
Ortho- Influenza A, B, C
Para- Measles, Mumps, RSV, Parainfluenza viruses, Human Metapneumovirus

Genome:
Ortho- Segmented (8 pieces) ssRNA of negative polarity
Para- Non-segmented ssRNA of negative polarity

Vision RNA Polymerase? Yes

Capsid? Helical

Envelope? Yes

Size:
Ortho- Smaller
Para- Larger

Surface spikes:
Ortho- HA and NA on different spikes
Para- HA and NA on same spikes

Giant cell Formation?
Ortho- No
Para- Yes

Question 2

General Characteristics (3)

Answer 2

Enveloped

Linear genome, negative sense ssRNA

Nom-segmented genome, hence all members antigenically stable

Question 3

Viral attachment?

Answer 3

HA glycoproteins and HN proteins

Question 4

Which age group mostly?

Answer 4

Children

Question 5

RSV General Information (5)

Answer 5

1- Most common cause of VIRAL LOWER RESPIRATORY TRACT infection of infants + children

2- Almost all children infected with RSV by their SECOND BIRTHDAY

3- Responsible for 50-90% of bronchiolitis and 5-40% of bronchopneumonia

4- In older children and adults, symptoms much milder

5- Reinfections common and may cause no more than cold

Question 6

Clinical Manifestation of baby with RSV (6)

Answer 6

Fever (typically low-grade)

CROUPY COUGH

Tachypnea

Cyanosis

Intercostal Retractions

Wheezing, rales, rhonchi (bubbling sound —> accumulation of fluid in airways)

Question 7

Parainfluenza Virus (3)

Answer 7

1- SECOND most common cause of LOWER RESPIRATORY TRACT infection in young

2- 75% of cases of CROUP

3- Reinfections URT

Question 8

PIV-1 and PIV-2 (4)

Answer 8

PIV-1 —> Croup in children
PIV-2 —> Less frequently detected

Both cause URT and LRT infection

Causes URT illness: Cold-like symptoms (fever, nasal congestion, pharyngitis, non-productive cough)

Question 9

PIV-3 (2)

Answer 9

More severe- Bronchiolitis, Bronchitis, Pneumonia

Otitis Media

Question 10

PIV-4a and b

Answer 10

Not recognized as often but may cause MILD-SEVERE respiratory tract illness

Question 11

Human Metapneumovirus (HMPV) (4)

Answer 11

Usually asymptomatic or mild: fever, runny nose, sore throat, cough

Respiratory illness in elderly and Immunocompromised: wheezing, bronchiolitis, difficulty breathing, pneumonia, poor feeding

By age 5 years most children infected

Single serotype with2 subtypes A and B

Question 12

Measles (4)

Answer 12

1- Acute, highly contagious

2- Fever with Rash

3- Frequent in developing countries

4- Developed countries —> Encephalitis

Question 13

Measles Pathogenesis (6)

Answer 13

1- Incubation Period 10-12 days

2- Prodromal Period (Non-specific symptoms) (Fever 39.5 or higher, cough, runny nose, conjunctivitis)

3- Koplik spots (small white spots develop inside mouth)

4- Maculopapular rash (3-4 days after first symptoms)

5- Centrifugal: Start on head and neck, then spreads to trunk, arms, legs

6- Fades in order of appearance

Question 14

Mumps (5)

Answer 14

1- Spread by SALIVARY AND RESPIRATORY secretions

2- Acute contagious childhood disease

3- ENLARGEMENT of one or both PAROTID GLANDS (Parotitis)

4- Mostly mild childhood disease, but in ADULTS, complications such as MENINGITIS or ORCHITIS common

5- More than 1/3 ASYMPTOMATIC

Question 15

Mumps Clinical Manifestations (3)

Answer 15

1- Prodromal period: Headache, Fever, Muscle aches, Malaise, Anorexia followed by rapid swelling of PAROTID GLANDS

2- Gland enlargement is painful, bilateral or unilateral

3- Complications in adults: ORCHITIS (could lead to temporary sterility or infertility in men), OOPHORITIS, MENINGITIS, ENCEPHALITIS

Question 16

MMR Vaccine

Answer 16

1st dose —> 12-15 months

2nd dose —> 4-6 years