Chickens 3 wk old, inoculated intranasally with a mesogenic (moderately virulent) strain of Newcastle disease virus, developed necrotic lesions of the mucous acini, predominantly of the middle turbinates. The infection subsequently spread to involve much of the rest of the mucosa, including mucous and ciliated epithelial cells, and other acini.
The early phase of adsorption of a virulent strain of the virus to the middle turbinates of chicks 5–21 days of age was studied by giving a standard inoculum intranasally to unanesthetized animals.
Variation in amounts adsorbed by individual chickens was large, but was minimized by making measurements on pools of turbinates from three chicks at intervals of 1, 3, and 5 hr after exposure of the excised turbinates to antibody, by washing, and by trypsinization. The virus released from the cells into the trypsin was designated as adherent virus, and the infectious virus in the cells after destruction of the cells by water grinding, as cell virus.
Paralysis of ciliary action by cocaine increased the number of infected cells in the turbinates about 10-fold at all three time intervals.
Pilocarpine injection before virus inoculation caused a large increase in the amount of infected cells 1 hr after virus administration, but was followed by a sharp drop in infected cells by 3 or 5 hr. Pilocarpine given after the virus decreased the number of infected cells and changed the relationship of infected cells to adherent virus.
Exposure of chicks to sustained or severe cold caused a similar but less marked effect. The drop in infected cells was restored to control values if chicks were returned to brooder temperatures.
The marked drop of infected cells produced by pilocarpine and cold in living chicks, and in cultures of chicken trachea (previous study), is consonant with the idea that virus has been adsorbed on mucus granules in the mucous cells of the turbinates and then has been reexcreted, as unincorporated virus, into the moving mucous sheet. A series of accessory data support this interpretation.