Viral infection of the upper respiratory tract Flashcards
which viruses cause Acute Infection with replication confined to respiratory mucosal surface?
Picornavirus (rhinovirus)
Coronavirus
Paramyxovirus (parainfluenza and respiratory syncytial virus)
Orthomyxovirus (Influenza)
Which viruses exhibit Persistent replication on respiratory mucosal surface?
EBV
Adenovirus
Papillomavirus
Which virsuses are most likely to exhibit Systemic replication (dissemination) after primary replication in respiratory tract?
Paramyxovirus (mumps, measles) Herpesviruses (EBV, VZV, HHV6, CMV) Rubella Picornavirus (polio), Other viruses: bunya, arena, parvo, pox, reo
What are the key features of Coronaviruses?
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
What virus cased SARS in 2003
MERS in 2013
coronavirus
Myxoviruses: what are the two classes?
Myxo, Greek for mucus.
These viruses bind to mucin protein on RBCs
include Paramyxoviruses from Orthomyxoviruses
Influenzavirus
Segmented (-) ssRNA
Nuclear replication
Enveloped
What viruses are found withing the Paramyxovirus genera?
What are defining features?
Mumps
Parainfluenzavirus 1-4
Newcastle disease virus
Cytoplasmic replication
non-segmented (-) ssRNA
Enveloped
What viruses are found within the Morbillivirus genera?
What are defining features?
Measles
Rinderpest
Canine distemper
Cytoplasmic replication
non-segmented (-) ssRNA
Enveloped
What viruses are found within the Pneumovirus genera?
What are defining features?
Respiratory syncytial virus
Cytoplasmic replication
non-segmented (-) ssRNA
Enveloped
How does influenza cause disease? What are the typical symptoms?
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
What differentiates Paramyxoviruses from Orthomyxoviruses?
paramyxoviruses are
non-segmented (-) ss RNA genome
little genetic variation
What causes croup?
Parainfluenza virus & Respiratory syncytial virus
What is croup? When it is most common?
What is it treated with?
What complications can arise?
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
What do these all cause? Which cases it the most?
Rhinovirus
Coronavirus
Influenza virus
Common cold (rhinovirus)
30-50%
10-15%
5-15%
What is the natural history of adenoviruses?
How infectious?
Morbidity high or low?
likely to infect where?
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.
What type of virus causes Pharyngoconjunctival fever?
adenovirus
What is the transmission for adenovirus?
Where are the sites of infection?
Where does the virus persist after infection?
What is needed for resolution?
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
Who are at risk for adenovirus?
When is infection most likely?
children
What can cause febrile respiratory illness that there is a vaccine for typically given to military?
Ad4 (adenovirus)
