Cattle with a low bovine leukemia virus proviral load are rarely an infectious source
Cattle with a low bovine leukemia virus proviral load are rarely an infectious source
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DOI：
10.14943/jjvr.66.3.157
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发表时间：
2018-08-01
影响因子：
0.4
通讯作者：
Norimine, Junzo
中科院分区：
文献类型：
--
作者：
Mekata, Hirohisa;Yamamoto, Mari;Norimine, Junzo
牛白血病病毒（BLV）是牛致死性b细胞白血病和恶性淋巴瘤的病原。具有较高BLV原负荷的牛在水平和垂直传播方面都具有较高的风险。因此，量化BLV的原病毒载量对于确定主要传染源和保护无BLV的牛不接触受感染的牛具有重要意义。在这项研究中，我们证实，在常规条件下，携带极低BLV原病毒载量的牛不会将病毒传播给无病毒的牛。我们总共观察了7次试验，其中一头感染blv的公牛被允许与57至92头没有blv的牛同居12或22个月。然后我们评估了病毒传播的频率。一头感染blv的公牛“原病毒载量非常低”（即，前病毒拷贝数少于100 /50 ng基因组DNA），在两次测试中有两次没有将病毒传播给任何没有病毒的牛。然而，在5次试验中的2次中，一头感染blv的牛“前病毒载量低”（即100至500拷贝/50纳克）将病毒传染给了3头没有病毒的牛。这些结果表明，“非常低的原病毒载量”感染blv的牛在常规条件下不传播病毒，而“低原病毒载量”的牛可以传播病毒，尽管传播率很低。我们相信本研究结果将促进构建有效的预防BLV感染和控制BLV传播的措施。
Bovine leukemia virus (BLV) is an etiological agent of fatal B-cell leukemia and malignant lymphoma in cattle. Cattle with higher BLV proviral loads represent a higher risk of both horizontal and vertical transmission. Therefore, quantifying the proviral load of BLV is important in identifying major infectious sources and protecting BLV-free cattle from exposure to infected cattle. In this study, we confirmed that cattle with very low BLV proviral loads did not transmit the virus to virus-free cattle under conventional conditions. We observed a total of 7 tests in which a BLV-infected bull was allowed to cohabit with 57 to 92 BLV-free cattle for 12 or 22 months. We then evaluated the frequency of viral transmission. A BLV-infected bull with a "very low proviral load" (i.e., fewer than 100 proviral copies/50 ng of genomic DNA) did not transmit the virus to any virus-free cattle in 2 out of 2 tests. However, a BLV-infected bull with a "low proviral load" (i.e., 100 to 500 copies/50 ng) transmitted the virus to a total of 3 virus-free cattle in 2 out of 5 tests. These results suggest that BLV-infected cattle with "very low proviral loads" do not transmit the virus under conventional conditions, while cattle with "low proviral loads" can transmit the virus, although at low rates. We believe that the results of this study will promote the construction of effective measures to prevent BLV infection and control the spread of BLV.