Objective: Macroscopic and microscopic lesions of experimentally induced ovine babesiosis with Babesia ovis.
Design: Experimental study.
Animals: Twelve ito 2- year -old native breed sheep (Chall).
Procedure: Babesiosis was induced by intravenous injection of Babesia ovis. These sheep were negative for babesial infection before the experiment. Six of them were splenectomized. Clinical symptoms were recorded and serological and hematological examinations were carried out. Four seriously affected sheep (three splenectomized and one intact) were necropsied and macroscopic lesions were recorded. The tissue samples were fixed in 10% neutral buffered formalin, embedded in paraffin, sectioned at 5tt and stained with H&E, Giemsa Gener’s and PAS for histopathology.
Results: Grossly, the liver was enlarged and dark brown in color and gallbladder was distended with watery bile. The kidneys were dark with cortical petechial and ecchymotic hemorrhages and moist on cut surface. Numerous subepicardial petechial hemorrhages were present. The lymph nodes were edematous and hemorrhagic. Gross examination of the CNS revealed edema and congestion of the brain and meninges. The lungs were diffusely congested and edematous. The cut surface of these organs was moist and the tracheal and bronchial lumina contained a large amount of frothy, pinkish edema fluid. The blood was thin and watery. Some carcasses
were icteric. Histopathologic examination revealed focal necrosis, lymphoplasmocytic pericholangitis and cholangiohepatitis and canalicular cholestasis in liver. Proliferative glomerulitis, congestion of glomerular capillaries and ischemic acute tubular necrosis was present. Lymphocytic epicarditis and endocarditis, lymphohistiocytic myocarditis together with zenkers necrosis of cardiac muscle fibers and hemorrhages were observed. Severe edema, mild lymphocytolysis and hemorrhagic lymphadenitis were present. Perineuronal and perivascular edema and status spongiosis were noticed in brain. Microscopically, acute alveolar edema and interstitial neutrophilic and macrophages infiltration were present. Congestion of skeletal muscles was also present.
Clinical implications: These findings indicate that the disease is more complex than a simple syndrome of intravascular hemolysis. The intense visceral congestion and pulmonary edema suggest that death may be partly due to circulatory shock associated with accumulation of toxins, release of vasoactive substances and anemic anoxia. J. Fac. Vet. Med Univ. Tehran. 59, 1:49-56, 2004
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