Morphological changes of chicken tracheas and tracheal organ cultures infected with avian infectious bronchitis virus studied in scanning electron microscope.

Chicken tracheas infected in vitro in organ culture and in vivo with avian infectious bronchitis virus (IBV) were studied by scanning electron microscopy. In in vitro infection in organ culture the columnar epithelial cells lining the tracheal ring lost their cilia and rounded up in 48 hr. There were numerous elevations and holes on the infected cell surface. Subsequently the cells sloughed off. In in vivo infection the tracheal epithelial cells lost their cilia in 4 days. These cells without cilia appeared bulging, and the surfaces were covered with microvillus-like structures. Subsequently a pseudomembrane was present in most areas. In 10 days postinfection the cilia started regenerating, and in 12 days postinfection there was complete regeneration of cells and cilia, giving a normal appearance to the trachea.