An outbreak of polio-encephalomalacia in cobalt-deficient sheep

Abstract

Extract In New Zealand two forms of polio-encephalomalacia have been recognized in sheep. The mild form is characterized clinically by blindness (amaurosis), and pathologically by laminar necrosis of the cerebral cortex (Mullins et al., 1958 Andrews, E. D. , Hart, L. I. and Stephenson, B. J. 1960. N.Z. J. agric. Res., 3: 364–364. [Taylor & Francis Online] [Google Scholar] ). The severe form is characterized clinically by a wide variety of neurological signs and pathologically by extensive cerebro-cortical necrosis (Hartley and Kater, 1959 Hartley, W. J. and Kater, Joan C. 1959. N.Z. vet. J., 7: 75–75. [Taylor & Francis Online] [Google Scholar] ). The mild form has a relatively high morbidity and low mortality, whereas the severe form has a low morbidity and a very high mortality.