Abstract
Introduction: A total of 32 young (1-3 months-old) lambs suffered from mortal neurological signs in a period of three months. The lambs were among the offspring of a herd of 300 sheep, in Tarhouna city, Libya. The affected lambs were initially treated with antibiotics, multivitamins and mineral supplements, however, none of these treatments attenuated the death toll among the small lambs. Methods: Three lamb carcasses were submitted to the National Center for Animal Health (NCAH) for post mortem examination. Gross pathological examination of the brains detected hydatid cysts and yellowish lesions within the cerebral cortex. Results: The histopathologic examination of the brain showed the presence of inflammatory lesions and necrotic features surrounded by granulomatous inflammatory patterns, which are accompanied by a few parasitic cysts. Ordinary and modified Ziehl-Neelsen stains for bacterial infection were performed, but the results did not strongly indicate bacterial infection. Toxoplasmosis, particularly T. gondii, and Neospora were first suspected. Immunohistochemistry testing for T. gondii did not show any conclusive indication for the presence of this pathogen. However, meticulous microscopic examination (100x) of the histopathologic features and the patterns of host-pathogen interaction of toxoplasmosis indicate that these lambs may have suffered from necrotic encephalitis associated with a different type of toxoplasmosis.