Abstract
In Kagoshima Prefecture, 210 calf congenital abnormalities were observed from June 1987 through May 1992. Abnormalities in 4 calves obviously differed from Akabane disease. The calves were born in the northwest area of Kagoshima from February to April 1991 and in March 1992. Macroscopically, the dilated lateral ventricle and hydranencephaly were evident in all the animals. Cerebellar hypoplasia and cerebellar defect were seen. Some showed arthogryposis or gelatinized-yellowish skeletal muscle of the extremitas. Histopathologically, nonpurulent encephalitis in the cerebrum was demonstrated. The cerebellar structure was remarkably disordered. Loss or marked decrease in the nerve cells in the spinal ventral-horn and runt muscle of the extremitas were apparent. Antibody to Aino virus only was detected in the calves by the neutralization test. In the northwest area, Aino virus was shown most active between mid-October and early November in 1990 and 1991. Antibody-positive rates were higher than those of other areas. The present results suggest Aino virus infection of calves and the possibility that Aino virus may be an etiologic agent of these congenital abnormalities.
