Avian encephalomyelitis virus ( aev ) is a picornavirus with a predilection for the central nervous system and other parenchymous organs of chickens that is transmited by the oral - faecal route . the virus may be spread by the vertical and horizontalroutes , and because of its great stability , contaminated areas may remain infectious for long periods . the egg - adapted van roekel strain is highly neurotropic and does not grow efficiently in the enteric tract of the chicken , and the field isolates of aev is usually enterotropic . despite this . the virion polypeptides of both naturally - occurring strains and the van roekel strain are antigenically identical 侵害鸡的中枢神经系统和其它实质性器官，该病毒通过口-粪途径传播，具有水平和垂直传播的能力。由于它极大的稳定性，被污染的区域可能长期保持传染性。鸡胚适应株vanroekel是高度嗜神经的，并且在鸡的肠道内不能有效的生长，而野毒株却是嗜肠道型的。
