Andoh Kiyohiko, Hayashi Takumi, Nishimori Asami, Matsuura Yuichi
National Institute of Animal Health, National Agriculture and Food Research Organization, 3-1-5 Kannondai, Tsukuba, Ibaraki, 305-0856, Japan.
Oita Livestock Hygiene Service Center of Oita Prefecture, 442 Onozuru, Oita, Oita, 870-1153, Japan.
Heliyon. 2024 Aug 17;10(16):e36201. doi: 10.1016/j.heliyon.2024.e36201. eCollection 2024 Aug 30.
Bovine viral diarrhea (BVD) is a serious disease in cattle and causes economic losses in the livestock industry. Bovine viral diarrhea virus (BVDV) is the causative agent of BVD and spreads among herds via persistently infected (PI) animals that shed large amounts of the virus throughout their lives. Hence, identifying, and culling PI animals and assessing the immune status against BVDV on farms are important strategies for controlling BVD. Additionally, estimating the time when individuals around PI animals were infected with the virus could also be supportive information to interpret a farm status. We herein constructed a BVDV-specific IgM capture ELISA using recombinant E2 antigen and applied it to detecting BVDV-specific IgM antibodies on farms with identified PI cattle. The IgM ELISA detected anti-BVDV IgM antibodies during approximately 2-3 weeks post infection and identified IgM-positive cattle on two farms with recognized PI cattle. Virus neutralization tests showed that almost all adult cattle had high virus neutralization antibodies against BVDV, and sero-positive and -negative cattle coexisted in young herds. In this situation, most of the IgM-positive cattle were in relatively young animals, implying that BVDV had been recently spreading in these young herds. Thus, our findings demonstrated that detecting IgM antibodies could be useful to know recent BVDV infection on farm on which PI cattle were identified.
牛病毒性腹泻（BVD）是牛的一种严重疾病，给畜牧业造成经济损失。牛病毒性腹泻病毒（BVDV）是BVD的病原体，通过终身大量排毒的持续感染（PI）动物在牛群中传播。因此，识别和淘汰PI动物以及评估农场对BVDV的免疫状况是控制BVD的重要策略。此外，估计PI动物周围个体感染病毒的时间也可以作为解释农场状况的辅助信息。我们在此使用重组E2抗原构建了一种BVDV特异性IgM捕获ELISA，并将其应用于在已识别出PI牛的农场中检测BVDV特异性IgM抗体。IgM ELISA在感染后约2至3周内检测到抗BVDV IgM抗体，并在两个已识别出PI牛的农场中鉴定出IgM阳性牛。病毒中和试验表明，几乎所有成年牛都具有针对BVDV的高病毒中和抗体，并且年轻牛群中存在血清阳性和阴性牛。在这种情况下，大多数IgM阳性牛是相对年轻的动物，这意味着BVDV最近在这些年轻牛群中传播。因此，我们的研究结果表明，检测IgM抗体有助于了解已识别出PI牛的农场中最近的BVDV感染情况。
