Epidemiological and clinico-pathological study of congenital defects in cattle

1985年11月至1986年4月，在日本九州岛观察到2000多头无脑积水和小脑发育不全的牛犊。他们出生时一般都很虚弱，神志不清，不能自己吸奶。大多数幼崽在几个小时后都能站起来，但没有一只表现出自我吸吮的能力。护理几天后只有少数病例出现自吸，但通常情况下仍不够充分，导致明显的生长迟缓。一些人表现出持续性的瘫痪。许多病例出现反张、痉挛、眼球震颤等神经症状。即使他们能走路，他们也只是漫无目的地行走，可能是因为视力障碍。一种新的奥尔比病毒，楚赞病毒，最初被怀疑，后来被证实是病原体。1987年，只收集到53例缺陷牛犊。多为骨骼、心脏和中枢神经系统疾病，未发现明显的阿卡巴内或楚赞病毒病征象。1988年，阿卡巴内病在3~6月间以低产仔牛居多。然而，它们在以下几个方面与本病的典型模式相区别：没有关节融合的先兆，相对较多的荷斯坦病例和一些合并小脑发育不良的病例。在研究期间，报告了两种遗传缺陷。1972年至1974年，宫崎市的一个地区发生了疑似8头日本黑牛犊的遗传性出血性素质；1980年至1982年，鹿儿岛发生了日本黑牛的先天性致死性皮肤缺陷。每一次都是由一头种公牛引起的，这些公牛后来被淘汰了。然而，这些缺陷仍然很少发现，可能是隐性基因造成的。

More than 2,000 calves with hydranencephaly and cerebellar hypoplasia was observed in Kyushu island, Japan during November, 1985 and April, 1986. They were generally weak and paretic at birth and could not suck milk by themselves. Most calves could stand several hours later, but none of them showed self-suck. Only a few cases showed self-suck after several days of nursing, but even then it usually was not enough, causing marked retarded growth. Some showed persistent paresis. Nervous signs such as opisthotonus, spasms and nystagmus were found in many cases. Even if they could walk, they only walked aimlessly probably due to disturbance of vision. A new orbi virus, Chuzan virus, was first suspected and later confirmed to be the causative agent.In 1987, only 53 cases of defective calves were collected. Most of them were classified as skeletal, cardial and central nervous system, but no obvious signs of Akabane or Chuzan virus diseases were found.In 1988, the moderate occurrence of Akabane disease mostly in cattle with low paritus was found between March and June. However, they were differentiated from the typical patterns of this disease in the following aspects; no preceding signs of arthrogryposis, relatively many cases of holstein and some cases complicated with cerebellar hypoplasia.During the research periods, two hereditary defects were reported. 'Hereditary hemorrhagic dithesis suspected in eight Japanese black beef calves' occurred in one area of Miyazaki during 1972 and 1974 and ' congenital lethal skin defects in Japanese black cattle' occurred in Kagoshima during 1980 and 1982. Each of them was caused by one stud bull and those bulls were eliminated later. However, these defects are still found rarely probably due to recessive gene.