Modified spinning top homogeneous spray apparatus for use in experimental respiratory disease studies.

The May spinning top generator was adapted to a modified Henderson tube for producing large aerosol particles (>4 mum) to obtain almost exclusive upper respiratory tract deposition of infectious aerosols in exposed mice. The system was installed in a biological safety cabinet to permit experimentation with pathogens. A novel mechanism utilizing parts from a machinists micrometer and the mechanical stage from a light microscope was developed for the spinning top generator as a means for precisely positioning the liquid feed needle. Aerosol light-scatter properties were continuously analyzed to provide relative measures of particle size distribution and aerosol concentration. When mice were exposed to influenza virus aerosols in which none of the virus was contained in particles with aerodynamic diameters <4 mum, essentially all of the virus was deposited in the upper respiratory tract tissues.