Institut Toulousain des Maladies Infectieuses et Inflammatoires (Infinity), Université de Toulouse, INSERM, CNRS, UPS, Toulouse, France.
Pathogenesis and Control of Chronic and Emerging Infections, University of Montpellier, INSERM, EFS, Montpellier, France.
Viruses. 2022 Jul 25;14(8):1619. doi: 10.3390/v14081619.
Usutu virus (USUV) is a neurotropic mosquito-borne flavivirus that has dispersed quickly in Europe these past years. This arbovirus mainly follows an enzootic cycle involving mosquitoes and birds, but can also infect other mammals, causing notably sporadic cases in humans. Although it is mainly asymptomatic or responsible for mild clinical symptoms, USUV has been associated with neurological disorders, such as encephalitis and meningoencephalitis, highlighting the potential health threat of this virus. Among the different transmission routes described for other flaviviruses, the capacity for some of them to be transmitted vertically has been demonstrated, notably for Zika virus or West Nile virus, which are closely related to USUV. To evaluate the ability of USUV to replicate in the placenta and gain access to the fetus, we combined the use of several trophoblast model cell lines, ex vivo human placental explant cultures from first and third trimester of pregnancy, and in vivo USUV-infected pregnant mice. Our data demonstrate that human placental cells and tissues are permissive to USUV replication, and suggest that viral transmission can occur in mice during gestation. Hence, our observations suggest that USUV could be efficiently transmitted by the vertical route.
乌苏图病毒（USUV）是一种神经嗜性蚊媒黄病毒，近年来在欧洲迅速传播。这种虫媒病毒主要遵循一个涉及蚊子和鸟类的地方性循环，但也可以感染其他哺乳动物，导致人类中出现明显的散发性病例。尽管它主要是无症状的或引起轻微的临床症状，但 USUV 与神经系统疾病有关，如脑炎和脑膜脑炎，突出了这种病毒的潜在健康威胁。在描述的其他黄病毒的不同传播途径中，已经证明其中一些病毒具有垂直传播的能力，特别是寨卡病毒或西尼罗河病毒，它们与 USUV 密切相关。为了评估 USUV 在胎盘内复制并进入胎儿的能力，我们结合使用了几种滋养层模型细胞系、来自妊娠第一和第三 trimester 的离体人胎盘外植体培养物以及体内感染 USUV 的怀孕小鼠。我们的数据表明，人胎盘细胞和组织允许 USUV 复制，并表明病毒在妊娠期间可以在小鼠中传播。因此，我们的观察结果表明，USUV 可以通过垂直途径有效地传播。
