Zoonotic viruses circulate in the natural reservoir and sporadically spill over into human populations, resulting in endemics or pandemics. We previously found that the Chaoyang virus (CYV), an insect-specific flavivirus (ISF), is replication-defective in vertebrate cells. Here, we develope a proof-of-concept mosquito-delivered vaccine to control the Zika virus (ZIKV) within inaccessible wildlife hosts using CYV as the vector. The vaccine is constructed by replacing the pre-membrane and envelope (prME) proteins of CYV with those of ZIKV, assigned as CYV-ZIKV. CYV-ZIKV replicates efficiently in Aedes mosquitoes and disseminates to the saliva, with no venereal or transovarial transmission observed. To reduce the risk of CYV-ZIKV leaking into the environment, mosquitoes are X-ray irradiated to ensure 100% infertility, which does not affect the titer of CYV-ZIKV in the saliva. Immunization of mice via CYV-ZIKV-carrying mosquito bites elicites robust and persistent ZIKV-specific immune responses and confers complete protection against ZIKV challenge. Correspondingly, the immunized mice could no longer transmit the challenged ZIKV to naïve mosquitoes. Therefore, immunization with an ISF-vectored vaccine via mosquito bites is feasible to induce herd immunity in wildlife hosts of ZIKV. Our study provides a future avenue for developing a mosquito-delivered vaccine to eliminate zoonotic viruses in the sylvatic cycle.

人畜共患病毒在天然宿主中传播，并偶尔蔓延到人群中，导致地方病或大流行。我们之前发现朝阳病毒 (CYV) 是一种昆虫特异性黄病毒 (ISF)，在脊椎动物细胞中存在复制缺陷。在这里，我们开发了一种概念验证蚊子接种疫苗，以使用 CYV 作为载体来控制难以接近的野生动物宿主体内的寨卡病毒 (ZIKV)。该疫苗是通过将 CYV 的前膜和包膜 (prME) 蛋白替换为 ZIKV 的蛋白而构建的，指定为 CYV-ZIKV。CYV-ZIKV 在伊蚊中有效复制蚊子并传播到唾液，未观察到性病或经卵巢传播。为了降低 CYV-ZIKV 泄漏到环境中的风险，对蚊子进行 X 射线照射以确保 100% 不育，这不会影响唾液中 CYV-ZIKV 的滴度。通过携带 CYV-ZIKV 的蚊虫叮咬对小鼠进行免疫，可引发强烈而持久的 ZIKV 特异性免疫反应，并提供针对 ZIKV 攻击的完全保护。相应地，免疫小鼠不能再将受攻击的 ZIKV 传播给幼稚的蚊子。因此，通过蚊虫叮咬使用 ISF 载体疫苗进行免疫接种是可行的，可以在 ZIKV 的野生动物宿主中诱导群体免疫。我们的研究为开发蚊子疫苗以消除森林循环中的人畜共患病毒提供了未来途径。