【摘要】 目的针对黑龙江省近几年夏季奶牛经常发生以高热、气喘和流涎等症状为主的疾病,给畜牧业造成严重经济损失,本文旨在研究其病原因素及感染牛中和抗体的变化趋势。方法本研究采集爆发高热病的牛群中患病牛乳汁和鼻液进行病毒分离,经CPE和扫描电镜观察、理化特性试验、血凝试验、病毒中和试验以及RT-PCR方法鉴定分离的病毒,最后应用病毒中和试验跟踪监测5头典型发病牛中和抗体13个月。结果从病料中分离到一种RNA病毒,能够产生典型的细胞融合样CPE,有囊膜和栅栏样纤突,但是没有血凝性,能够与参考毒株牛副流感病毒3型抗血清发生病毒中和反应,HN基因的序列分析发现与牛副流感病毒3型HN基因同源性最高达99.6%。发病牛中和抗体跟踪监测结果显示康复期抗体效价是急性期的4倍以上,同时可见感染牛的中和抗体效价在6-8个月内能够维持在1:25～1:27,然后开始下降,最后维持在1:22～1:23之间。结论综上所述确定分离毒株是牛副流感病毒3型,进一步证实该病毒是引起本牛群高热病的病因之一,而且感染后中和抗体效价至少在6个月以内能够维持在较高的水平。更多还原

【Abstract】 To study this pothogeny and neutralization antibody titer change of infected cattle,the milk and blenna narium of fever symptomatic dairy cattle were collected in this study to isolate virus.The virus were identified by observing the CPE on MDBK cell,scanning electron microscope,physical and chemical properties test,hemagglutination test,viral neutralization test,and RT-PCR.The neutralization antibody of five pathogenetic cattle was monitored by means of viral neutralization test for thirteen month.A RNA virus isolated from the samples could lead CPE of cell fusion with envelope and projections from the virion envelope but no hemagglutination,and it could neutralize antiserum for the reference bovine parainfluenza virus type 3(BPIV-3) BN-1 strain.The homology was up to 99.6% between HN gene and Japanese BPIV-3(GenBank accession number Y00114 and D84095).The results of neutralization antibody titer of cattle monitored showed that antibody titer for convalescent period was four times more than acute stage.Meanwhile the neutralized antibody titer of infected bovine could be maintained at 1∶25 to1∶27 for 6 to 8 months,then began to descent,and finally remained stable at 1∶22 to 1∶23.Overall,the isolated strain was identified as BPV-3.It was further confirmed that the BPIV-3 was one of etiological factors for the hyperthermia of cattle herd.The neutralizing antibody titer could be maintained at a high level for at least six months.更多还原