Avian Pathol: Circovirus inclusion bodies in intestinal muscle cells of a canary.
Multiple cytoplasmic inclusion bodies were observed in the
intestinal smooth-muscle cells of an adult canary from an aviary with a
history of high mortality (50%). Grossly, a mild enteritis was the only
lesion appreciable. Smears of the proventricular content contained a few
megabacteria (Macrorhabdus ornithogaster). The intestinal inclusions
were found in high numbers in all parts of the tract examined. They
appeared round to oval, amphophilic, and hyaline in sections stained
with hematoxylin and eosin, and magenta with Feulgen stain. Inclusions
of the same type were occasionally detectable in the wall of splenic and
pancreatic arteries. No inclusions or lesions were seen in the other
organs examined. Transmission electron microscopy of the intestinal wall
revealed circovirus-like particles, either in paracrystalline arrays or
loose arrangements, mostly within the cytoplasm of the intestinal-muscle
cells. Polymerase chain reaction amplification and sequence analysis
confirmed infection with canary circovirus.