The ovine nervous syndrome in Côte-d’Ivoire. I. An Epidemiological and clinical study, diagnostic methods and treatment

Abstract

The ovine nervous syndrome in Cote-d’Ivoire is similar to the cerebrocortical necrosis (CCN) due to vitamin B1 deficiency. All classical symptoms of CCN were observed (locomotor ataxia with subsequent paralysis) and histological evidence for polioencephalomalacia was given. However, the circumstances for occurrence of the disease are very different in the two cases, i.e. CCN is a disease encountered in young fattening ruminants in developed countries while the ovine nervous syndrome is mainly observed in Côte-d’Ivoire during the dry season when pastures become sparse and dry and when the feed supply is insufficient. Thus, the main cause, which is rather univocal, is a sudden decrease in the nutritive value of the diet, but the accurate etiopathogenesis of the disease has not yet been determined. In a flock where 10-30 % of the animals are ill, the mortality may reach 80-90 %. No classical biochemical assays were specific enough to establish a precise diagnosis of the nervous syndrome. However, it should be pointed out that the CK (creatinine kinase) values very regularly rose and that the ASAT (aspartate aminotransferase) values were high in 75 % of the cases. In the present African field conditions, the precise diagnosis is based on the efficiency of the vitamin B1 treatment and, for the dead animals, on the histological analysis of the brain.