Microbiology
Summary
The Pneumoviridae family of viruses contains the respiratory syncytial virus (RSV) from the Orthopneumovirus genus and the human metapneumovirus (HMPV) from the Metapneumovirus genus. Both of these are enveloped, negative-sense RNA viruses characterized by a helical nucleocapsid. The G protein of these viruses facilitates the virus's attachment to respiratory epithelial cells, initiating infection, while the F protein triggers the fusion of infected host cells with adjacent uninfected cells, leading to the formation of multinucleated structures known as syncytia.
Transmission of these viruses primarily occurs through direct contact or large respiratory droplets. While typically resulting in mild respiratory diseases in healthy individuals, they can cause severe infections in vulnerable populations such as infants and the elderly. Premature children and those with asthma are at a higher risk of severe HMPV infection. Among adults, it's a less frequent cause of community-acquired pneumonia but can exacerbate chronic obstructive pulmonary disease (COPD). RSV is the leading cause of pneumonia and bronchiolitis in infants. High-risk groups for RSV include premature children and those aged 2 and below with underlying lung conditions. To mitigate its spread, especially in medical settings, it's crucial to isolate RSV-infected patients and adopt droplet precautions. For treatment and prevention, ribavirin can be used for immunocompromised patients (though it's contraindicated in pregnancy), and palivizumab, a monoclonal IgG antibody, offers preventive measures for high-risk children.
Lesson Outline
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FAQs
Respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) are both RNA viruses that belong to the Pneumoviridae family. RSV and HMPV are major causes of respiratory infections in humans, especially lower respiratory tract infections such as bronchiolitis and pneumonia.
The primary virulence factors for RSV and HMPV are their surface proteins. For both viruses, the G protein facilitates attachment to respiratory epithelial cells, initiating infection. Additionally, the F protein promotes cell-to-cell fusion, leading to the formation of multinucleated structures called syncytia. These proteins not only aid in infection but also play roles in evading the host immune response..
Populations at heightened risk of severe HMPV infections include infants, particularly those born prematurely, and individuals with asthma. Both premature children and asthma patients have increased vulnerability due to their compromised respiratory systems or underdeveloped immune defenses?
RSV and HMPV enter the body through the nose or mouth and travel down to infect the lungs, causing inflammation and infection in the alveoli. This can lead to bronchiolitis and pneumonia, particularly in more vulnerable populations like infants, older adults, and people with weakened immune systems.
