进境蓝舌病抗体阳性动物带毒分析及检疫处理研究

Virus carrier analysis andentry-exit quarantine of bluetongue virus seropositive animals in international trade

为评估进口蓝舌病病毒(BTV)抗体阳性动物的感染状态,分析其带毒风险,对从国外进口的9批19714头动物,无菌采集全血分离血清,采用竞争ELISA方法检测BTV抗体。对BTV抗体检测阳性的动物,采集抗凝血,采用OIE推荐的套式RT-PCR和荧光RT-PCR方法进行检测,同时将样品送往蓝舌病参考实验室进行病毒分离鉴定,以确定动物的蓝舌病感染状态。结果 9批动物中检出28头BTV抗体阳性动物,但核酸检测和病毒分离鉴定的结果均表明这些BTV抗体阳性动物并不携带有非感染性和感染性病毒粒子。结合9个批次的进口动物并无明显临床表现,且进口动物来源地也无蓝舌病(BT)的疫情发生,据此根据OIE《陆生动物卫生法典》条款,判定这些抗体阳性动物为带毒阴性。本研究通过对BTV抗体阳性动物的带毒分析,并结合OIE确定BTV感染的要求,对BTV口岸隔离检疫流程提出建议,以指导动物检疫工作,阻止病原经口岸传入。

The objective of the present study was to investigate the infection status and virus carrier state of bluetongue virus （BTV） seropositive animals. In this study, 19714 sera were aseptically collected from 9 batches of imported animals and tested for anti-BTV antibodies by competitive ELISA. For the seropositive animals, the presence of BTV was detected using real-time RT-PCR or RT-nPCR from anticoagulant-treated whole blood according to the recommendation of OIE. Meanwhile, to confirm the infection status, all positive samples were sent to the BT reference laboratory at Yun Nan Entry-Exit Inspection and Quarantine Bureau and subjected to virus isolation. Among the19714 animals that were tested, 28 were positive for antibodies against BTV. However, infectious or noninfectious virus could not be detected by virus isolation （VI） technique or nucleic acid tests. Furthermore, there were no significant clinical symptoms present in the 9 batches of imported animals, and the origin place had no BT epidemic. Based on the above results and relevant items in the OIE＂ Terrestrial Animal Health Code＂, the conclusion was drown that there was no virus presence in seropositive animals. Also, the quarantine procedure for BTV was proposed in this study according to the detection of virus from BTV seropositive animal and the requirement for definite diagnosis of BT by OIE, which will be useful for specific guidelines for trading animals quarantine and preventing potential invasion of BTV.