Human Parainfluenza Viruses
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.
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]
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]
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)