van Maanen C, Sloet van Oldruitenborgh-Oosterbaan M M, Damen E A, Derksen A G
Animal Health Service, Deventer, The Netherlands.
Equine Vet J. 2001 Mar;33(2):191-6. doi: 10.1111/j.2042-3306.2001.tb00600.x.
An outbreak of neurological disease caused by EHV-1 infection is described with emphasis on diagnosis and prognosis for recumbent horses. In April 1995, an outbreak of the neurological form of Equine herpesvirus type 1 (EHV-1) occurred in a well-managed riding school with 41 horses: 34 horses showed a temperature spike and 20 some degree of neurological signs, of which 10 were nursed intensively in the indoor arena of the riding school for 3 to 20 days, 8 having to be maintained in slings for 2-18 days, while 9 needed bladder catheterisation b.i.d. for 2-16 days. Within the first 3 days, one horse was subjected to euthanasia and another horse died. Postmortem examination revealed a mild vasculitis with perivascular mononuclear cuffing and axonal degeneration in the central nervous system. Clinical diagnosis was confirmed by serology and virology: 28 horses seroconverted in one or more tests during the outbreak, whereas 12 had already high CF and SN titres in the first sample, suggestive of recent infection. Virus was isolated from nasal swabs of 4 horses, and identified as EHV-1 with type-specific monoclonal antibodies. Restriction enzyme analysis revealed that the EHV-1 strains from this outbreak belonged to genome type EHV-1.IP. The electropherotypes were identical to those from another, epidemiologically unrelated, outbreak of neurological disease 2 months earlier. The timing of the temperature spikes and seroconversions indicated that the infection was probably introduced by a horse purchased 3 weeks before neurological signs occurred. At follow-up one year later, the 10 horses that showed mild neurological signs had recovered completely. Of the 8 horses that survived intensive care, 3 had returned to around their former performance level (2 of which had been in slings), while the other 5 had become pasture-sound. At follow-up 4 years later, all pasture-sound horses had been subjected to euthanasia because of persistent mild ataxia and incontinence. In conclusion, the prognosis for recumbent horses due to EHV-1 infection is grave. For virological diagnosis, extensive and strategic sampling of febrile in-contact horses is required, and the EHV-1-specific glycoprotein G (gG) ELISA is a valuable tool for specific serological diagnosis of EHV-1 infection causing neurological disease.
本文描述了一起由EHV - 1感染引起的神经系统疾病暴发，重点关注卧地不起马匹的诊断和预后。1995年4月，一所管理良好的骑术学校发生了1型马疱疹病毒（EHV - 1）神经型疾病的暴发，该校共有41匹马：34匹马出现体温骤升，20匹马有一定程度的神经症状，其中10匹马在骑术学校的室内场地进行了3至20天的强化护理，8匹马需用吊索维持2 - 18天，9匹马需要每天两次膀胱插管2 - 16天。在最初3天内，1匹马实施了安乐死，另一匹马死亡。尸检显示中枢神经系统有轻度血管炎伴血管周围单核细胞套袖状浸润和轴突变性。血清学和病毒学检查确诊了临床诊断：暴发期间28匹马在一项或多项检测中出现血清转化，而12匹马在首个样本中CF和SN滴度就已很高，提示近期感染。从4匹马的鼻拭子中分离出病毒，并用型特异性单克隆抗体鉴定为EHV - 1。限制性酶切分析表明，此次暴发的EHV - 1毒株属于基因组型EHV - 1.IP。其电泳型与2个月前另一起流行病学上无关联的神经疾病暴发的毒株相同。体温骤升和血清转化的时间表明，感染可能是由在出现神经症状前3周购入的一匹马引入的。一年后的随访中，10匹有轻度神经症状的马已完全康复。在重症监护下存活的8匹马中，3匹恢复到了接近以前的表现水平（其中2匹曾使用吊索），而另外5匹在牧场环境中状况良好。4年后的随访中，所有在牧场环境中状况良好的马因持续存在轻度共济失调和尿失禁而实施了安乐死。总之，EHV - 1感染导致的卧地不起马匹预后严重。对于病毒学诊断，需要对发热的接触马匹进行广泛且有策略的采样，EHV - 1特异性糖蛋白G（gG）ELISA是对引起神经疾病的EHV - 1感染进行特异性血清学诊断的宝贵工具。
