Inoculation of human volunteers with parainfluenza viruses types 1 and 3 (HA 2 and Ha 1)

Abstract

Eighteen human volunteers were inoculated intranasally with various doses of a strain of parainfluenza 1 virus. Nine became infected, and six of these developed illnesses resembling the common cold. Twenty volunteers received parainfluenza 3 virus. Eight became infected, of whom six developed cold-like illnesses, one had an illness like influenza, and one remained well. The colds produced were clinically indistinguishable from those occurring after instillation of washings containing a cold virus, but the incubation period was longer in the parainfluenza virus infections. © 1959, British Medical Journal Publishing Group. All rights reserved.