Parainfluenza Flashcards
What type of genetic material do parainfluenza viruses (PIV) have?
Single-stranded, negative-sense RNA
To which virus family do parainfluenza viruses belong?
Paramyxoviridae
Are parainfluenza viruses enveloped or non-enveloped?
Enveloped
Mention the four major serotypes of human PIV.
- PIV-1
- PIV-2
- PIV-3
- PIV-4
T/F. PIVs don’t have hemagglutinin and neuraminidase.
False
What are the structural characteristics of parainfluenza virions?
- Pleomorphic
- Lipid bilayer envelope derived from host cell
Mention the 6 viral proteins encoded by PIV’s RNA.
- Nucleocapsid protein (NP)
- Phosphoprotein (P)
- Matrix protein (M)
- Fusion glycoprotein (F)
- Hemagglutinin-neuraminidase glycoprotein (HN)
- RNA polymerase (L)
What proteins are targets for neutralizing antibodies?
HN and F proteins
Which proteins make the nucleocapsid core?
NP, P and L
This glycoproteins are critical for attaching the virus to the host cell wall.
HN proteins
After attachment, this protein mediates virus-cell membrane fusion and infection.
F protein
Where does viral replication occur?
Cytoplasm
What shape does the nucleocapsid has?
Helical
Which cells do PIVs preferentially infect?
Cilliated epithelial cells
Where does initial replication occur?
Epithelial cells of the nose and oropharynx
How is parainfluenza virus transmitted?
- Direct person-to-person contact via large respiratory droplets
- Contact with fomites contaminated with respiratory secretions
At what age does initial PIV infection typically occur?
Before the age of 5
Which PIV serotype affects up to 50% of children within their first year of life?
PIV-3
When do PIV-1 and PIV-2 typically cause initial infections?
Between ages 3 and 5
T/F. PIV is the second most common viral cause of hospitalization in children.
True
Primary disease associations for PIV-1 and PIV-2.
Croup (Laryngotracheobronchitis) in children
Primary disease associations for PIV-3.
Pneumonia and bronchiolitis
Primary disease associations for PIV-4.
Mild upper respiratory infections
When do PIV-1 and PIV-2 cause seasonal outbreaks?
During fall
When does PIV-3 cause epidemics?
During spring
Which PIV serotype is more common in the autumn and winter months?
PIV-4
What range of illness severity can PIV infections cause?
From mild cold-like symptoms to life-threatening pneumonia
T/F. Most PIV infections require hospitalization.
False
What type of respiratory infections are more common in children?
Upper respiratory infections
What complications can arise from upper respiratory tract PIV infections in children?
Otitis media and sinusitis
What are the typical symptoms of PIV-induced croup?
- Fever, rhinorrhea, pharyngitis
- Barking cough, stridor, dyspnea, chest wall retractions
T/F. PIV-2 disease is generally less severe than PIV-1.
True
Which PIV serotype is associated with distal lung involvement, particularly in infants under 6 months old?
PIV-3
Which PIV serotype is usually associated with mild upper respiratory infections or asymptomatic infections?
PIV-4
What are the three primary methods for diagnosing PIV?
- Culture
- Antigen detection
- PCR
What are the best specimens for diagnosing PIV?
Swabs, aspirates, and washes from the nasopharynx or orophraynx
T/F. There are rapid antigen kits for PIV detection.
False; there aren’t
T/F. There are no proven antiviral treatments for parainfluenza.
True
T/F. There is no vaccine approved for parainfluenza virus.
True
