RESUMO
Objective Parainfluenza virus is an important pathogen of lower respiratory tract infections in infants and young children.This study was to search for a method for rapid culture and identification of human parainfluenza viruses from nasal swabs. Methods Nasal swab specimens were collected from 0-5 years old children with acute respiratory tract infection.The specimens were inoculated onto 96 plates with prefabricated LLC-MK2 cells and then centrifuged for 1 hour at 3000 r/min and also inoculated using the traditional culture method, followed by addition of virus mainte-nance medium containing 4 μg/mL TPCK trypsin.The cytopathic effect was observed daily, and hemagglutination and blood absorption tests were done at 2, 5, and 8 days after inoculation.In case of posi-tive result of either test, the specimen was subjected to immunofluo-rescence staining. Results Six strains of parainfluenza virus were isolated from the 83 nasal swab specimens, with a positive rate of 7.2%.There was a significant difference in the rate of separation be-tween the rapid and traditional culture methods after 2 days of culturing (7.2%vs 0%, P<0.05).The infected cells produced a cy-topathic effect that characterized by syncytium and crush formation.Hemagglutination and blood adsorption tests were positive at 4℃and negative at the room temperature.Immunofluorescence staining exhibited specific apple green fluorescence. Conclusion The method for rapid culture and identification of human parainfluenza viruses in nasal swab specimens was successfully established, which can be used to obtain and identify parainfluenza viruses with virulence and biological activity in 2 days.