Vector competence of biting midges and mosquitoes for Shuni virus

Background
Shuni virus (SHUV) is an orthobunyavirus that belongs to the Simbu serogroup. SHUV was isolated from diverse species of domesticated animals and wildlife, and is associated with neurological disease, abortions, and congenital malformations. Recently, SHUV caused outbreaks among ruminants in Israel, representing the first incursions outside the African continent. The isolation of SHUV from a febrile child in Nigeria and seroprevalence among veterinarians in South Africa suggests that the virus may have zoonotic potential as well. The high pathogenicity, extremely broad tropism, potential transmission via both biting midges and mosquitoes, and zoonotic features warrants prioritization of SHUV for further research. Additional knowledge is essential to accurately determine the risk for animal and human health, and to assess the risk of future epizootics and epidemics. To gain first insights into the potential involvement of arthropod vectors in SHUV transmission, we have investigated the ability of SHUV to infect and disseminate in laboratory-reared biting midges and mosquitoes.
Methodology/Principal findings
Culicoides nubeculosus, C. sonorensis, Culex pipiens pipiens, and Aedes aegypti were orally exposed to SHUV by providing an infectious blood meal. Biting midges showed high infection rates of approximately 40–60%, whereas infection rates of mosquitoes were lower than 2%. SHUV successfully disseminated in both species of biting midges, but no evidence of transmission in orally exposed mosquitoes was found.
Conclusions/Significance
The results of this study show that different species of Culicoides biting midges are susceptible to infection and dissemination of SHUV, whereas the two mosquito species tested were found not to be susceptible.

### 背景
舒尼病毒（Shuni virus, SHUV）是隶属于辛布血清群（Simbu serogroup）的正布尼亚病毒属（Orthobunyavirus）病毒。该病毒已从多种家养动物及野生动物体内分离得到，与神经系统疾病、流产及先天性畸形相关。近期，舒尼病毒在以色列反刍动物种群中引发暴发，这是该病毒首次在非洲大陆以外区域被检出。此前研究从尼日利亚一名发热患儿体内分离到舒尼病毒，南非兽医群体中的血清阳性率数据也提示该病毒具备人畜共患潜力。鉴于其高致病性、极广泛的组织嗜性、可通过吸血蠓与蚊子两种媒介传播，以及人畜共患特性，舒尼病毒亟需被优先纳入后续研究范畴。目前仍需补充更多研究数据，以精准评估其对动物与人类健康的风险，并预判未来兽疫与流行病暴发的可能性。为初步探究节肢动物媒介在舒尼病毒传播过程中的潜在作用，本研究针对实验室饲养的吸血蠓与蚊子，开展了舒尼病毒感染与播散能力的相关实验。

### 方法与主要发现
本研究通过感染性血餐途径，对嗜蛛库蠓（Culicoides nubeculosus）、索诺拉库蠓（C. sonorensis）、尖音库蚊（Culex pipiens pipiens）及埃及伊蚊（Aedes aegypti）进行经口暴露感染。实验结果显示，库蠓的感染率较高，约为40%~60%，而蚊子的感染率则低于2%。舒尼病毒可在两种库蠓体内成功播散，但经口感染的蚊子未发现病毒传播证据。

### 结论与意义
本研究结果表明，不同种类的库蠓均对舒尼病毒的感染与播散具有易感性，而本次测试的两种蚊子则不具备该易感性。