Ataxia/paresis syndrome of sheep in West Africa associated with bilateral multifocal cerebrospinal poliomalacia

Between 1976 and 1981 a specific neurological disorder of sheep was observed in Ghana. It was encountered on eight properties on some of which it was responsible for losses of up to 72 per cent of the sheep stock in some years. The condition affected mainly adult ewes, and was characterised clinically by a brief period of ataxia, followed by paresis prostration and death in four to five days. Morphological examination of nine affected animals revealed significant lesions only in the central nervous system. These consisted of oedema of the intracellular glial compartment and bilateral, sometimes symmetrical, foci of spongy transformation, malacia and haemorrhage in the grey matter of the brain stem, cerebellum and spinal cord. The aetiology of ataxia/paresis syndrome was not determined but some possibilities are discussed in the context of other naturally occurring and experimental focal malacic disorders in animals.