Parainfluenza viral infections in children: correlation of shedding with clinical manifestations.

Children presenting with acute respiratory disease to a private group practice in the fall of 1975 were studied to: (1) evaluate the efficacy in a pediatric office of a simple technics of obtaining nasal washes for the diagnosis of parainfluenza virus infections and (2) to determine the quantities of virus shed in relation to clinical characteristics. The nasal wash technic proved feasible for an office or clinic. Parainfluenza virus type 1 was recovered from 26 (74%) of 35 children with croup and from 40 (56%) of the total 72 children presenting with any form of respiratory illness. Virus was recovered significantly more often from children with croup and from those of younger age. The mean quantity of virus in 26 nasal washes was 2.97 log10 TCID50/ml. The shedding of greater quantities was correlated with younger age and the more frequent occurrence of laryngitis, pharyngitis, and fever.