Transmission electron micrograph of parainfluenza virus. Two intact particles and free filamentous nucleocapsid

Human parainfluenza viruses (HPIVs) are a group of four distinct serotypes of single-stranded RNA viruses belonging to the paramyxovirus family.^[1]

Parainfluenza viruses can be detected via cell culture, immunofluorescent microscopy, and PCR.

[edit] Clinical significance

They are the second most common cause of lower respiratory tract infection in younger children. Together, the parainfluenza viruses cause ~75% of the cases of Croup.

Repeated infection throughout the life of the host is not uncommon. Symptoms of later breakouts include upper respiratory tract illness as in a cold and sore throat. The incubation period of all four serotypes is 1 to 7 days. In immunosuppressed people, such as transplant patients, parainfluenza virus infections can cause severe pneumonia, which is often fatal.^[2]

[edit] Prevention

Though no vaccines currently exist, research is underway.^[3]

Parainfluenza viruses last only a few hours in the environment and are inactivated by soap and water.^[4]

[edit] Types

There are four serotypes.^[5] These include:

• HPIV-1 (most common cause of croup; also other upper and lower respiratory tract illnesses typical)
• HPIV-2 (causes croup and other upper and lower respiratory tract illnesses)
• HPIV-3 (associated with bronchiolitis and pneumonia)
• HPIV-4 (includes subtypes 4a and 4b)

[edit] Notes

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