Respiratory Viruses I, II, & III Flashcards
In general, symptoms from a viral infection depend on ______________.
where the virus has infected (e.g., nasopharynx, upper airway) and not on the specific virus itself
Name the viral syndrome based on where it infects.
Rhinitis (nasal turbinate) Pharyngitis Laryngitis Tracheitis Bronchitis Bronchiolitis Bronchopneumonia
What viruses most commonly infect the respiratory tract?
Influenza Parainfluenza Coronavirus Rhinovirus Adenovirus Respiratory syncytial virus Human metapneumovirus
Some viruses prefer different ______________.
temperatures; Rhinovirus, for instance, prefers to replicate at 33º (which is the temperature of the nasopharynx)
Describe the three patterns of viral replication.
- Acute infection with replication confined to respiratory mucosal surface: RSV, Coronovirus, Picornavirus, Parainfluenza virus, and Othomyxovirus
- Persistent replication confined to mucosal surface: EBV, HPV, and adenovirus
- Primary infection followed by systemic infection: VZV, HHV6, Poxvirus, Paramyxovirus, and Rubella
What family is influenzavirus in?
Orthomyxoviridae
The only RNA virus that replicates in the nucleus is ______________.
Influenzavirus
Give a rundown on Influenzavirus.
- ssRNA
- Negative sense
- Enveloped
- Segmented
The paramyxoviridae family includes ______________.
- Paramyxovirus: Mumps and Parainfluenza
- Morbillivirus: Measles
- Pneumovirus: RSV
- Henipavirus: Hendra and Nipah
What do the H and N stand for in influenza nomenclature?
Envelope glycoproteins:
•H: hemagglutinin
•N: neuraminidase
What organisms can influenza A, B, and C infect?
A: humans and many other animals
B: humans
C: humans
Influenza vaccines target which strains of influenza?
A and B
The surface proteins of __________ are the most variable.
influenza strain A
Very few people infected with ____________ are asymptomatic.
influenza
Research shows that about __________ people are infected per case of influenza.
three to nine
True or false: in rare cases, influenza can develop systemic viremia.
False. Influenza is confined to the respiratory mucosa.
It is estimated that about ___________ influenza deaths per year could be prevented by better vaccination rates.
20,000
What’s the difference between antigenic drift and antigenic shift?
•Antigenic drift is the accumulation of point mutations that leads to immune escape.
–Occurs in all strains of influenza
•Antigenic shift is the sudden accumulation of new surface proteins from other virions, such as in a person who got infected with two strains of A.
– Occurs only in strain A because that is the only one that can move from animals to humans
(“Shift is Sudden. DRIft occurs DRIp by DRIp.”)
Amantadine blocks ____________.
M2
Why do paramyxoviruses have less variation than orthomyxoviruses?
Paramyxoviruses are not segmented!