Epidemiological, clinical, etiological and histopatological evaluation of delayed enzootic ataxia outbreaks in kids and lambs

摘要

> size="2" face="Verdana, Arial, Helvetica, sans-serif">An outbreak in 46 kids and 36 lambs with delayed enzootic ataxia (EA) raised in a single farm in the State of Pernambuco, Brazil, in 2001 and 2002 was described. The incidence was lower in 2001 (46.3% in kids and 24.2% in lambs) than in 2002 (100% in both species); only in 2001 the incidence was higher in kids (P0.002). All newborns with EA died, but one lamb and one kid. The clinical case was different according to the age of onset of EA. The animals between 30 and 45d old showed both fore and hindlimbs paralysis with muscular spasticity, followed by death. Animals older than 45d had only hindlimbs spasticity or flaccid paralysis followed by death. Only the under 45 days old kids presented head nodding. Axonal degeneration, spheroids, gliosis, and demyelination in the ventral lateral horns of the spinal cord were detected. Newborns less than 45d old had those lesions mainly in the cervical region, while the older in the lumbar region; only the kids had cerebellar lesions. The available diet to the herd had adequate levels of copper, but the liver copper concentration was low in animal with EA (45.8mg kg-1 D.M.); the antagonizing elements to the copper (molybdenum, sulfur and zinc) were normal, but the iron levels either in soil (8,600mg kg-1) and feedstuffs (284mg kg-1) were high. Excessive dietary intake of iron might have caused the copper deficiency in the newborns.