Enzootic ataxia in red deer (Cervus elaphus) in Argentina

Abstract

Enzootic ataxia is a pathology that causes slow and progressive paralysis of the hind limbs in red deer and has been related to copper (Cu) deficiency. This condition is not seen until deer are about 9 months old. The objective of this paper is to describe a clinical case of enzootic ataxia in red deer kept in captivity in Argentina. The problem started with two pregnant female deer that showed hind limb weakness. One was slaughtered for necropsy. Blood and organ samples were taken, and the latter were kept in formaldehyde at 10%. A necropsy of the foetus was also carried out and a liver sample was taken. Grass and water were analyzed. Cu, Fe, Zn, Mo and SO₄ levels were measured in grass, while total salt, SO₄ , Ca, Mg, Na and Cl levels were measured in water. Disease prevalence was 0.14%. Liver Cu values were 14.6 ppm and 337 ppm DM in the female and foetus respectively. Blood Cu level in the female was 0.5 μg/ml and haematocrit was 46%. In spinal cord a general medullar myelin sheath loss was found, but it was more severe in dorsal regions of the medulla. Vacuolization of white substance with no inflammatory response was also observed. Although liver Cu levels in the slaughtered female were lower than those considered as limiting, cupraemia was within the normal range. This is a commonly observed characteristic in Cu deficiency. Cu liver values in the foetus were also below the normal range. As this is a cronic disease, it is probable that the animals were exposed to a low Cu level diet for a long time. This condition could have been worsened by the high Cu demand during foetal growth in the last third of the gestation period. Since this disease is usually found in certain geographical areas and appears seasonally, it is important to take blood samples at the time of higher risk (beginning of spring) in order to carry out an early diagnosis. Therefore, according to the clinical, laboratory and epidemiological data, it is concluded that the diagnosis corresponds to enzootic ataxia due to Cu deficiency.