ABSTRACT
Based on serological and molecular analyses, HPIV are subdivided into four types (HPIV-1, HPIV-2, HPIV-3, and HPIV-4). In addition, two subtypes (HPIV-4A and HPIV-4B) are recognized in HPIV-4, and subgroups/genotypes in HPIV-1 and HPIV-3 have been also reported. HPIV are the second most common cause of lower respiratory tract infections in young children (after HRSV) and account for ~75% of the cases of croup. The close relatives of HPIV (Sendai virus (mouse PIV-1), bovine PIV-3, simian PIV-10,
Newcastle disease virus, Yucaipa virus, Kunitachi virus, avian PIV-3 to 9, La-piedad-Michoacan Mexico porcine virus, simian PIV-5 and PIV-41 (related to HPIV-2), canine parainuenza virus (CP2)) are responsible for diseases of varying severity in animals [1].
