Organ cultures of respiratory epithelium infected with rhinovirus or parainfluenza virus studied in a scanning electron microscope

Organ cultures of bovine tracheal epithelium were infected with a rhinovirus or a strain of parainfluenza type 3 virus, and the epithelial surfaces were studied by scanning electron microscopy. When washed free from mucus, normal control cultures showed a thick carpet of normal cilia, whereas the two viruses each produced specific morphological abnormalities. In rhinovirus-infected cultures, degenerating ciliated and nonciliated cells with finely granular surfaces were rapidly extruded from the epithelium. The denuded epithelial surface was relatively smooth, and showed some evidence of squamous metaplasia. By contrast, in cultures infected with parainfluenza type 3 virus, damage developed more slowly and the epithelial surface was ultimately covered with a profuse array of short microvillous projections. In thin sections, some of these were shown to be the sites of viral maturation.

Mycoplasma-virus interrelationships in mouse tracheal organ cultures

The effects produced by single and mixed infections with Mycoplasma pulmonis and influenza A/PR-8 virus were studied in mouse tracheal organ cultures. M. pulmonis multiplied in the tracheal organ cultures, producing inhibition of ciliary activity and histologic tissue damage. The organism grew in close association with the cell membranes but did not appear to attach directly to the membranes or the cilia. Influenza A virus also replicated in tracheal organ cultures, producing ciliary inhibition and more extensive cytopathologic changes. Virus particles were seen by electron microscopy to attach to and cause clumping of the cilia. Simultaneous infection of the organ cultures with mycoplasma and virus resulted in more rapid inactivation of ciliary activity and greater tissue damage than occurred when the cultures were infected with only mycoplasma or virus. Presence of the virus appeared to have no effect on the growth of the mycoplasma; however, the mycoplasma partially interfered with virus replication.

The tissue localization of Mycoplasma meleagridis in turkey embryos

Mycoplasma meleagridis appears to localize primarily in the respiratory tissues of the developing turkey embryo. This was determined by the daily collection throughout the incubation period of smears of embryonic tissues from 261 fertile turkey eggs. The tissues were examined using fluorescent antibody procedures and the earliest detection from positive tissues were: day 6, blastoderm (10%); day 8, sinus (44%) and peritoneum (55%); day 19, lung (11%) and trachea (44%); day 23, air sacs (62%).