This study provides a review of the transmission, pathophysiology, and clinical manifestation of respiratory syncytial virus infection.
Respiratory syncytial virus (RSV) is a common respiratory pathogen with a bimodal distribution, mostly affecting the pediatric and geriatric populations. Affected healthy adults are usually asymptomatic, but severe infection can occur in elderly, immunocompromised, or other high-risk populations. A study in the journal Cureus reviewed the transmission, pathophysiology, and clinical manifestations of RSV infection.
The Role of Close Contact and Contaminated Surfaces
Transmission occurs through large droplet inoculation in the eyes, nose, or mouth due to close contact with RSV-infected subjects or autoinoculation via contaminated fomites or skin.
Replication and Spread of Respiratory Syncytial Virus
After inhalation and passage across the mucus membranes, RSV infects the airway epithelial cells of the upper respiratory tract. It then reaches the lower respiratory system and bronchioles, where viral replication is more effective. Ciliated cells in the bronchial epithelia and type-I alveolar pneumocytes are primarily targeted. Viral mRNA is transcribed in the cytoplasm of the host cell by the viral RNA-dependent RNA polymerase complex into positive-sense anti-genome intermediates needed to replicate new negative-sense genomes packed into virion particles. RSV virions are assembled near the plasma membrane, from where they detach and are released.
Impact on Respiratory Epithelial Cells and Inflammatory Response
RSV infection causes severe deterioration of respiratory epithelial cells. Proinflammatory cells are drawn to the infection site. There is leakage of plasma proteins due to increased capillary permeability. This process also inhibits surfactant function. Proinflammatory mediators that cause strong bronchoconstriction are released in severe infection.
Clinical Manifestation in the Pediatric Population
Initial symptoms are similar in all groups, comprising nasal congestion and a low-grade fever, followed by a productive cough. Lower respiratory tract infection frequently occurs in infants 2–3 days after symptom onset. Infants and children can present with rhinitis, pharyngitis, fever, apnea, pneumonia, bronchiolitis, laryngotracheitis, hypoxemia, and dehydration, with bronchiolitis being the most common progression. RSV infection can also lead to long-term complications like atelectasis, hyperinflation, otitis media, RSV-associated hepatitis, respiratory failure, hyponatremia, meningitis, etc.
Clinical Manifestation in Geriatric and Immunocompromised Populations
Elderly and immunocompromised individuals present with symptoms similar to pediatric patients; however, with increased severity and lower respiratory system involvement, which can be attributed to delayed diagnosis due to early symptoms mimicking influenza or the common cold.
The typical initial presentation is that of nasal congestion progressing to lower respiratory tract symptoms in 3–4 days, such as productive cough, wheezing, and dyspnea. Clinical manifestations of RSV infection in older adults, elderly patients, and immunocompromised individuals include rhinorrhea, hoarseness, cough, fever, sinusitis, headache, wheezing, dyspnea, respiratory failure, etc.
Immunocompromised patients are predisposed to otalgia and sinusitis, which should raise suspicion of RSV infection in this population. RSV-associated complications in adults, the elderly, and immunocompromised patients include pneumonia, bronchiolitis, respiratory failure, hypoxemia, and exacerbations of COPD, congestive heart failure, and asthma.
Source
Kaler, J., Hussain, A., Patel, K., Hernandez, T., & Ray, S. (2023). Respiratory Syncytial Virus: A Comprehensive Review of Transmission, Pathophysiology, and Manifestation. Cureus, 15(3), e36342. https://doi.org/10.7759/cureus.36342