Pathological studies on chlamydiosis in parakeets (Psittacula krameri manillensis)

Abstract

SUMMARYHistological, immunohistochemical and ultrastructural findings are described in 20 parakeets (Psittacula krameri ntanillensis) affected with chlamydiosis. The main histological lesions consisted of focal necrosis in the liver and adrenal gland, lymphocytic depletion with fibrin exudation in the splenic sinuses and follicles and fibrinopurulent airsacculitis. In these lesions basophilic chlamydial inclusion bodies were found. Macrophages and plasma cells increased mainly in the liver and spleen. Immunohistochemically. more chlamydial inclusion bodies were observed in cells of various organs and tissues including epithelial cells, capillary endothelium and proliferated macrophages. With an electron microscope, the chlamydial inclusion bodies were shown to consist of chlamydial organisms in developmental stages. Concurrent lesions of pulmonary herpesvirus infection appeared frequently in the present cases and seemed to have a close relationship with the chlamydiosis onset.

Chlamydia psittaci infections in birds: A review on the pathogenesis and histopathological features

“…Livers of affected birds may show a dilatation of sinusoids with infiltration of mononuclear cells, lymphocytes, and heterophils (18,34). Histological examination of naturally infected imported parakeets showed focal necrosis of the liver with an infiltration of heterophils, macrophages, and plasma cells (34). Proliferated and swollen Kupffer cells engulfed yellowish-green pigment thought to be haemosiderin.…”

“…Some shedders are frequently seen (23). Serofibrinous or fibrinopurulent air sacculitis, pericarditis, and conjunctivitis, associated with basophilic intracytoplasmic inclusions, occur in septicaemic chlamydiosis in psittacine birds (34). Chlamydiosis in birds is characterized histologically by necrotizing and proliferative changes associated with chlamydial inclusion bodies (34).…”

“…Lesions concurrent with chlamydiosis but without inflammatory reaction (eosinophilic intranuclear inclusion bodies and syncytium formation) have been observed in the respiratory epithelium of the trachea, atria of the lung, and air sacs. In Japan herpes virus is often isolated from the lungs of imported, chlamydia-infected parakeets (34). Varying degrees of congestion and oedema of the lung parenchyma were noted.…”

“…In the respiratory system, lung consolidation resulting from focal mononuclear cell infiltration, oedema, congestion, and haemorrhage can be observed (15,32). Livers of affected birds may show a dilatation of sinusoids with infiltration of mononuclear cells, lymphocytes, and heterophils (18,34). Histological examination of naturally infected imported parakeets showed focal necrosis of the liver with an infiltration of heterophils, macrophages, and plasma cells (34).…”

“…The necrosis in the liver and other organs is most probably due to a direct effect of proliferating chlamydial organisms within cells. Immunohistochemical examination of paraffin-embedded sections was used to localize chlamydial antigen (34). In the liver, the antigen was found in necrotic areas, hepatocytes, bile duct epithelium, and swollen macrophages.…”