The problems associated with investigation of respiratory disease
in calves are examined and the need for a laboratory model study
A germ free mouse colony is described and evaluated in terms of
residual disease. Methods are described for exposing germ free mice
to aerosols of parainfluenza 1 (Sendai)virus. The distribution of
viras within lung tissue was ascertained using immunofluorescent stains.
The interaction of Sendai viras with the germ free mouse was measured
by titrating virus in lung tissue. The interaction of the germ free
mouse with Sendai virus was measured by histological quantitation.
A method for comparing the uninfected animal with the infected was
developed to produce a numerical count of bronchiolar mucosal cells
per millimetre of basement membrane.
The effect of climate on the function of respiratory physiology
and pathology is reviewed. The effect of varying environmental
temperature and relative humidity on mice infected with Sendai virus
is examined. Temperature and relative humidity are both shown to
affect the pathogenesis of the disease.
It is concluded that a cooler environment (10°C) allows a higher
virus titre to develop with a resultant increase in cellular
destruction, while a lower relative humidity (55%) delays bronchiolar
mucosal cell regeneration during the post viral recovery phase.