Viral infection of the upper respiratory tract

Question 1

which viruses cause Acute Infection with replication confined to respiratory mucosal surface?

Answer 1

Picornavirus (rhinovirus)
Coronavirus
Paramyxovirus (parainfluenza and respiratory syncytial virus)
Orthomyxovirus (Influenza)

Question 2

Which viruses exhibit Persistent replication on respiratory mucosal surface?

Answer 2

EBV
Adenovirus
Papillomavirus

Question 3

Which virsuses are most likely to exhibit Systemic replication (dissemination) after primary replication in respiratory tract?

Answer 3

Paramyxovirus (mumps, measles)
Herpesviruses (EBV, VZV, HHV6, CMV)
Rubella
Picornavirus (polio), 
Other viruses: bunya, arena, parvo, pox, reo

Question 4

What are the key features of Coronaviruses?

Answer 4

Named for their “crown”of spikes” - lipid bilayer envelope
(+) ssRNA virus
Most strains cause cold-like symptoms
Rare new strains cause lethal respiratory diseases
SARS in 2003
MERS in 2013

Question 5

What virus cased SARS in 2003

MERS in 2013

Answer 5

coronavirus

Question 6

Myxoviruses: what are the two classes?

Answer 6

Myxo, Greek for mucus.

These viruses bind to mucin protein on RBCs

include Paramyxoviruses from Orthomyxoviruses

Question 7

Influenzavirus

Answer 7

Segmented (-) ssRNA
Nuclear replication
Enveloped

Question 8

What viruses are found withing the Paramyxovirus genera?

What are defining features?

Answer 8

Mumps
Parainfluenzavirus 1-4
Newcastle disease virus

Cytoplasmic replication
non-segmented (-) ssRNA
Enveloped

Question 9

What viruses are found within the Morbillivirus genera?

What are defining features?

Answer 9

Measles
Rinderpest
Canine distemper

Cytoplasmic replication
non-segmented (-) ssRNA
Enveloped

Question 10

What viruses are found within the Pneumovirus genera?

What are defining features?

Answer 10

Respiratory syncytial virus
Cytoplasmic replication
non-segmented (-) ssRNA
Enveloped

Question 11

How does influenza cause disease? What are the typical symptoms?

Answer 11

aerosol inoculation of virus > replication in respiratory tract> desquamation of mucus secreting and ciliated cells > influenza syndrome marked by:

Fever (usually high) 
Headache 
Tiredness (extreme) 
Cough 
Sore throat 
Runny or stuffy nose 
Body aches 
Diarrhea and vomiting

Question 12

What differentiates Paramyxoviruses from Orthomyxoviruses?

Answer 12

paramyxoviruses are

non-segmented (-) ss RNA genome
little genetic variation

Question 13

What causes croup?

Answer 13

Parainfluenza virus & Respiratory syncytial virus

Question 14

What is croup? When it is most common?

What is it treated with?

What complications can arise?

Answer 14

Croup = laryngotracheobronchitis
Peak incidence in winter
Starts like a cold in adults and infants
Infants may develop a distinctive barking cough, called croup

Commonly treated at home with steam and humidifiers
Complications include pneumonia and respiratory distress

Question 15

What do these all cause? Which cases it the most?

Rhinovirus
Coronavirus
Influenza virus

Answer 15

Common cold (rhinovirus)

30-50%
10-15%
5-15%

Question 16

What is the natural history of adenoviruses?

How infectious?

Morbidity high or low?

likely to infect where?

Answer 16

Widespread in nature, infecting birds, many mammals and humans

100 serotypes, 47 can infect humans

Most people have been infected with at least 1 type by age 15

Adenovirus infections are very common,

most are asymptomatic

Most infections involve the respiratory or gastrointestinal tracts or the eye.

Question 17

What type of virus causes Pharyngoconjunctival fever?

Answer 17

adenovirus

Question 18

What is the transmission for adenovirus?

Where are the sites of infection?

Where does the virus persist after infection?

What is needed for resolution?

Answer 18

many

aerosol, Fecal oral route, close contact, fingers, opthalmologic instruments

virus affects mucoepitheliod layers of upper respiratory and GI tract, conjunctivea,, cornea
virus persists in lymphoid tissue (tonsils, adenoids, pryers patch)

Antibody is essential for recovery

Question 19

Who are at risk for adenovirus?

When is infection most likely?

Answer 19

children

Question 20

What can cause febrile respiratory illness that there is a vaccine for typically given to military?

Answer 20

Ad4 (adenovirus)