From the Guidelines
Parainfluenza virus (PIV) is primarily transmitted through direct person-to-person contact via respiratory droplets and secretions, as well as indirect contact with contaminated surfaces or objects. When an infected person coughs, sneezes, or talks, they release virus-containing droplets that can be inhaled by others nearby 1. PIV can also spread through indirect contact when someone touches a contaminated surface or object and then touches their eyes, nose, or mouth. The virus can survive on environmental surfaces for several hours, making fomite transmission possible in settings like daycares, schools, and healthcare facilities. Close contact with infected individuals in crowded environments significantly increases transmission risk. PIV is highly contagious during the early stages of infection, often before symptoms fully develop, which contributes to its efficient spread. Individuals are typically contagious from about one day before symptoms appear until 7-10 days after symptom onset. Some key points to consider about PIV transmission include:
- Direct person-to-person contact via respiratory droplets and secretions is the primary mode of transmission
- Indirect contact with contaminated surfaces or objects can also spread the virus
- Close contact with infected individuals in crowded environments increases transmission risk
- Good hand hygiene, avoiding close contact with sick individuals, and disinfecting frequently touched surfaces are effective preventive measures against PIV transmission 1. It's worth noting that while other studies discuss transmission of similar viruses, such as influenza 1, the most relevant and recent guidance for PIV specifically is from 1.
From the Research
Transmission of Parainfluenza Virus
- The exact mechanism of Parainfluenza virus (PIV) transmission is not explicitly stated in the provided studies, but it can be inferred that it is primarily spread through respiratory droplets and contact with infected individuals 2, 3, 4, 5.
- PIV infection can lead to a wide variety of clinical syndromes, ranging from mild upper respiratory illness to severe pneumonia, and can be severe and life-threatening in immunocompromised individuals 2, 3, 5.
- The virus can enter cells by fusing directly at the cell surface membrane, and understanding the steps in this process can lead to possible strategies to prevent fusion and inhibit infection 6.
Modes of Transmission
- Respiratory droplets: PIV can be spread through respiratory droplets that are released when an infected person talks, coughs, or sneezes 3, 4, 5.
- Contact with infected individuals: PIV can also be spread through contact with infected individuals, such as touching or shaking hands 2, 3, 5.
- Contaminated surfaces: It is possible that PIV can also be spread through contact with contaminated surfaces, although this is not explicitly stated in the provided studies.
High-Risk Groups
- Immunocompromised individuals: PIV infection can be severe and life-threatening in immunocompromised individuals, such as those with compromised immune systems, elderly, or chronically ill persons 2, 3, 5.
- Children: PIV infection can also be severe in children, particularly those under the age of 6 years 3, 4, 5.