Histopathology
The most critical histopathological finding in liver sections of
diseased birds was the presence of inclusion bodies in the hepatocytes
(Figure 2), appearing as large basophilic intranuclear inclusion bodies
surrounded by a pale halo. Many hepatocytes were degenerated and swollen
with vacuolated cytoplasm. Infrequently, necrosis of scattered
hepatocytes occurred. Moreover, there was lymphocytic and heterophilic
hepatitis. These inflammatory infiltrates appeared clearly around the
central vein. Additionally, there was widening and infiltration of
sinusoids with lymphocytes, heterophils, and histiocytes (Figure 3).
Histopathological sections of testicles from infected birds revealed
degeneration of spermatozoa, spermatids, Sertoli cells, and Leydig
cells. In the interstitial tissue, there was intertubular hemorrhage and
large vacuoles. Also, there was dilation of seminiferous tubular lumens
that contained necrotic debris and were devoid of spermatozoa, a lesion
reported for the first time in the present study (Figure 4).