研究背景:
非洲猪瘟(African swine fever,ASF)是由非洲猪瘟病毒(African swine fever virus,ASFV)引起猪 的一种烈性、高度接触性传染病,引起猪的死亡率可 高达100%,与传统猪瘟相 似且综合症状复杂难辨。ASFV属非洲猪瘟病毒科非洲猪瘟病毒属,是一种有囊膜的双链 DNA病毒,也是唯 一的虫媒DNA病毒。
中国将非洲猪瘟列为一类动物疫病,世界动物卫生组织(OIE)将其列为必须报告的动物疫病。近年来,中国周边国 家格鲁吉亚、亚美尼亚、阿塞拜疆、俄罗斯、乌克兰等 国先后发生多起非洲猪瘟疫情。今年8月以来我国发生首例非洲猪瘟疫情以来,已相继有12个省(直辖市)报道非洲猪瘟疫情,当前中国对非洲猪瘟 的防控形势十分严峻,这就使得掌握 ASF的简便、快速精确的现场诊断方法变得尤为重要。
截至2018年10月29日全球非洲猪瘟疫情
截至10月29日,全球有37个国家和地区向OIE报告发生非洲猪瘟疫情,其中13个国家已经根除。2018年新发生疫情的国家包括匈牙利(4月)、保加利亚(8月)、中国(8月)、比利时(9月)。
2018年以来,全球有波兰、俄罗斯、拉脱维亚、捷克、罗马尼亚、摩尔多瓦、乌克兰、匈牙利、保加利亚、比利时、科特迪瓦、南非、乍得、赞比亚和中国等15个国家发生4183起非洲猪瘟疫情。
(来源:农业农村部、世界动物卫生组织)
结果速览
本研究中,分析了ASFV毒株的p54基因序列,选择高度保守的区域设计引物和探针,以确保所有基因型都能被检测。生物素和FITC分别标记在特异引物的5’端作为探针,在CPA扩增之后,产物的两端分别与FITC和生物素连接,然后通过嵌入在测试条、测试线以及对照线上的抗体进行鉴定,以指示检测结果。CPA技术不需要专门的设备,反应时间也大大减少。
试验操作不需要专业的实验室和人员,并且程序易于执行。采用该CPA方法检测来自乌干达的临床样本时,与高灵敏度的实时PCR技术结果高度一致(44/45)。在CPA条带中,只有一个样品经实时PCR检测阳性(CT值=34),而CPA方法为阴性。综上所述,建立的一种以P54基因为靶点与免疫层析试纸条(CPA条)相结合的ASFV CPA条带检测法特异性强、灵敏度高、简便易行、成本低,对ASF有可靠的监测潜力。
ABSTRACT: African swine fever (ASF) is a highly contagious disease caused by African swine fever virus (ASFV) in domestic pigs and wild boars. Up to now, no commercial vaccines against ASF are available. With the rapid development of international trade and modern logistics and the frequent trade activities with Africa, Europe and neighboring countries, the risk of cross-border transmission of ASF to ASF-free regions is increasing.
Therefore, there is an urgent need to establish a convenient and low-cost diagnostic method for rapid and on-site detection of the virus to timely implement the control measures. In this study, a cross-priming amplification in combination with immunochromatographic strip (CPA-strip) was established for rapid detection of ASFV. The CPA-strip assay displayed no cross-reactivity to other swine viruses. The minimum detection limit of this method was 200 copies.
Forty-five clinical swine blood samples collected from Uganda were examined by the novel assay, 6 out of 45 samples were tested positive for ASFV. The agreement rate between the CPA-strip assay and the universal probe library-based real-time PCR was 97.8% (44/45). In addition, a total of 100 tissue samples and 57 blood samples from Chinese swine herds were tested to be negative. We concluded that the established CPA-strip method is
suitable for on-site detection of ASFV.
该课题得到中国博士后科学基金(No.2016M591313)国家自然科学基(31700139号)、国家重点研究开发计划(2017YFD0501603和2016YFD0500 105)和中国哈尔滨应用技术研究开发项目(编号:2015RQQYJ056)的支持。
参考文献:
1.Yao Gao, Xing-Yu Meng, Huawei Zhang, Yuzi Luo, Yuan Sun, Yongfeng Li, Muhammad Abid,Hua-Ji Qiu.Cross-priming amplification combined with immuno-chromatographic strip for rapid on-site detection of African swine fever virus. Sensors and Actuators B: Chemical 274(2018): 304-309| DOI: 10.1016/ j.snb.2018.07.164 |
2.http://www.moa.gov.cn/ztzl/fzzwfk/yqxx/201810/t20181029_6161807.htm