Polioencephalomalacia Caused by Thiamine Deficiency in Sheep ofBasrah Province, Iraq

POLIOENCEPHALOMALACIA caused by thiamine deficiency in sheep of Basrah province have been diagnosed. This current research was conducted on 44 local sheep breeds 1-3 years old and of both sexes reared in Basrah province. Ten clinically normal local sheep breeds were selected as a controls. Diseased sheep show various clinical manifestations, such as anorexia, head pressing and muscular tremors, opisthotonus and nystagmus, incoordination and ataxia, Furthermore, circling with lateral deviation of the head (41%), recumbency and inability to stand and some sheep exhibit blindness (18.1%). Moreover, significant increase in respiratory and heart rate of diseased animals in comparison with control animals , while rumen motility was decreased significantly in affected animals compared to control group . Considerable changes were detected in biochemical parameters of affected sheep in comparison with controls. The gross pathological features and histopathological examination of dying or slaughtered sheep show pale discoloration of the dorsal cerebral cortex, especially the occipital lobes, which might indicate a necrosis. However, gross lesions might also represent flattening of cerebral gyri, hemorrhages, necrosis to cavitations in the gray matter of the occipital and temporal regions. The histopathological examinations revealed gliosis as well to vacuolative changes of some neurons. The white matter of brain showed also gliosis with wallerian degeneration of some neuronal axons and severe vaculation of neuronal cell body and central chromatolysis of some neurons. thiamine estimated by simple spectrophotometric method. It is concluded that thiamine deficiency is an important disease which could affect domesticated animals and result in economic losses, Therefore, good care and good management will be the ideal way to control the disease.