Ultrastructural changes in the nasal turbinate bones of pigs in early infection with Bordetella bronchiseptica.

The ultrastructural changes in the turbinates of young pigs killed four, seven, 14 and 28 days after intranasal inoculation (dpi) with Bordetella bronchiseptica were restricted to osteoblasts. In a few cells irregularities and evagination of the nuclear membrane were associated with enlargement of the Golgi apparatus at four dpi. By seven dpi many osteoblasts had these changes and also a dilatation of the endoplasmic reticulum while mitochondria retained normal definition: an amorphous degeneration occurred within the enlarged Golgi apparatus. These features had progressed at 14 and 28 dpi to produce shrunken osteoblasts with small, irregular nuclei, a grossly distended endoplasmic reticulum, absent or degenerate Golgi apparatus, but apparently intact mitochondria. At this stage the numbers of osteoid fibres were greatly reduced and macroscopic hypoplasia of the turbinates was observed.