Human parainfluenza viruses belong to the paramyxovirus genus (those of the real flu are, on the other hand, orthomyxoviruses), of which four main serotypes are recognized (HPIV 1-4).
(RSV) and the causative agent of measles. In particular, parainfluenza viruses belonging to the genera Respirovirus (human parainfluenza virus 1, HPIV-1 and human parainfluenza virus 3, HPIV-3) and Rubulavirus (HPIV-2 and HPIV-4) are recognized Parainfluenza viruses are negative single-stranded RNA viruses.HPIV 1-4 are closely related for the manifestations they are capable of causing, but are distinct from each other from a genomic, serological and antigenic point of view.
HPIV-1 and HPIV-2
Human parainfluenza virus serotype 1 (HPIV-1, Human Parainfluenza Virus-1) is responsible for the most important epidemics that usually occur every two years. Clinically, HPIV-1 is typically the cause of laryngotracheobronchitis (like HPIV-2).
Parainfluenza virus serotypes 1 and 2 can cause infections of both the upper and lower respiratory tract.
HPIV-3
HPIV-3 outbreaks occur annually, especially in spring and summer. Infections caused by this parainfluenza virus are often associated with bronchiolitis, bronchitis and pneumonia.
HPIV-4
Human parainfluenza virus 4 (HPIV-4) is the most rarely isolated serotype, so it is not very well known. The infections it causes are minor and are therefore diagnosed less frequently.
