Respiratory syncytial virus Flashcards
What’s RSV family?
Pneumoviridae
T/F. RSV is a naked virus.
False, its enveloped
What type of nucleic acid does RSV has?
Single-stranded, negative-sense RNA
How does RSV initially appear under electron microscopy?
Tubular structure
What is the mature form of RSV under electron microscopy?
Spherical structure
What feature is present on the viral envelope of RSV?
Transmembrane glycoprotein spikes
Which proteins make up the RSV nucleocapsid complex?
- Nucleoprotein (N)
- Phosphoprotein (P)
- Polymerase (L)
- Transcription processivity factor (M2-1)
This protein accumulates on the inner envelope and is crucial for viral morphogenesis.
Matrix protein (M)
Mention the 3 surface glycoproteins present in RSV.
- Fusion protein (F)
- Attachment protein (G)
- Viroporin protein (SH)
What is the function of the RSV nonstructural proteins NS1 and NS2?
They inhibit type I and type III interferon activity
What proteins does the M2 gene encode, and what are their functions?
- M2-1: transcription processivity factor
- M2-2: Transcriptional regulatory protein
What is the primary attachment protein of RSV?
G protein
Which receptor does the RSV G protein bind to and in which cells?
CXCR3; respiratory epithelial and immune cells
Which RSV protein facilitates viral attachment by binding to nucleolin (the most important receptor)?
F protein
What is the role of the F protein in cell-to-cell contact?
It induces fusion forming syncytia
What structural changes does the F protein undergo?
Prefusion to postfusion form
This protein is critical for viral assembly and budding.
M protein
T/F. RSV causes a significant disease burden annually, unlike many other respiratory viruses.
True
When does RSV peak in drier climates?
During cooler months
Which age group is most affected by severe lower respiratory tract illness due to RSV?
Previously healthy infants within their first year of life
Which illnesses are commonly associated with primary RSV infection in infants?
Bronchiolitis and pneumonia
What are the main ways RSV is transmitted?
- Direct contact
- Contaminated objects
T/F. Small-particle aerosols are more likely to transmit RSV.
False, they are less likely
Which cells are primarily affected by RSV in the respiratory epithelium?
Ciliated columnar cells
Besides ciliated columnar cells, which other cells can RSV infect?
Type I and II pneumocytes
What type of imune infiltration is seen in RSV primary infection?
Lymphocytic peribronchial infiltration with CD69+ monocytes and edema
What happens to the bronchiolar epithelium in RSV infection?
Proliferation and necrosis of the bronchial epithelium
What causes airway obstruction in RSV?
Sloughed epithelium and increased mucus secretion
Why are infants at increased risk of atelectasis in RSV?
They have underdeveloped collateral channels
Which two conditions often occur together in RSV-infected infants?
Bronchiolitis and pneumonia
What are the key pathological features of RSV pneumonia?
Interstitial infiltration of mononuclear cells, edema, and necrosis
What are giant multinucleated syncytial cells, and why do they form in RSV?
Fused cells caused by RSV-induced cell fusion
How common is severe RSV disease after the first infection in healthy children?
Uncommon
Which part of the respiratory tract is primarily affected in RSV primary infections?
Lower respiratory tract
What is the most common clinical manifestation of RSV in young children?
Bronchiolitis, followed by peumonia and tracheobronchitis
What are the common symptoms of RSV when infection is confined to the upper respiratory tract?
Fever and otitis media
What are the most common symptoms among preschool-aged children with RSV seeking outpatient care?
- Wheezing
- Labored breathing
T/F. Hoarseness and laryngitis are common in RSV.
False
How does RSV typically begin?
As an URI with nasal congestion and cough
What are the signs of RSV progression to lower respiratory tract disease?
- More prominent and productive cough
- Increased respiratory raye, dyspnea, and intercostal retractions
- Bronchiolitis
- Crackles and wheesinf on auscultation
- Swings in oxygen saturation
Which lobes commonly show subsegmental opacities in RSV?
Right upper and middle lobes
What is a common complication of RSV infection in young children?
Acute otitis media
Which age group is more commonly affected by RSV-associated acute otitis media?
Children older than 1 year
What are the most common bacterial pathogens associated with RSV otitis media?
- Streptococcus pneumoniae
- Haemophilus influenzae
- Moraxella catarrhalis
Which populations are at higher risk of RSV infections among older children?
- Families with young children
- Schools
- Child care facilities
What type of illness do most recurrent RSV infections cause in older children?
Upper respiratory tract illnesses
What are typical symptoms of RSV infection in adults?
Upper respiratory symptoms followed by lower respiratory symptoms
Which symptom is more common with RSV than with other respiratory viruses?
Wheezing
Which adult populations are at the highest risk for severe RSV disease?
- Elderly
- Those with cardiopulmonary disease
- Immunocompromised patients
What symptoms were more common in RSV than influenza among healthy adults?
Earache, sinus pain, persistentmcough, and wheezing
Which groups of chidren are most likely to require hospitalization due to RSV?
- Premature infants
- Children with underlying conditions
Which demographic and environmental factors increase the risk of severe RSV infection?
- Male sex
- Crowded living conditions
- Lower socioeconomic status
- Tobacco smoke exposure
- Lack of breastfeeding
What is one of the most significant acute complications of RSV in young infants?
Apnea
What is the most frequently identified bacterial infection in RSV-hospitalized infants?
Urinary tract infections
What is one of the most common long-term complications of RSV bronchiolitis in infancy?
Wheezing
How does RSV infection affect the immune response?
It triggers a response similar to allergic sensitization
Gold standard to diagnose RSV.
RT-PCR
Most children and adults with RSV require supportive care, including:
- Comfort measures
- Fever control
- Adequate fluid intake
This is the only approved specific treatment for RSV lower respiratory tract disease in hospitalized infants.
Ribavarin
