Abstract
The commonest cause of common cold is infection by one of many rhinoviruses, but coronaviruses and a variety of other common respiratory syncytial, influenza and adenoviruses may cause clinically indistinguishable symptoms. Early studies showed that colds were likely to spread via infected droplets expelled from the respiratory tract, and more recently it has been shown that manual transmission is also possible. The comparative importance of the two routes of spread is not yet evaluated.
Intranasal inoculation of chicks with a mesogenic strain of Newcastle disease virus produced a localized infection of the middle turbinate which was histologically demonstrable 18 hours after inoculation. There was destruction of mucous cells of individual acini in the under surface of the middle turbinate, and the infection rapidly spread to ciliated and goblet cells and to neighboring acini. Normal nasal mucosa was essentially restored in 2 weeks after inoculation. These results were supported by the mucociliary function study, viral recovery from throat swabs and serum antibody titer. The infection is sequentially comparable to common cold of man.
Susceptibility and morbidity of upper respiratory tract to virus infections may be affected by the change of conditions of the host such as dehydration, protein deficient malnutrition or SO2 exposure rather than by the amount of inoculum.
