UMR ASTRE, CIRAD, Montpellier, France.
IPPTS, DHPI EA 7292, Université de Strasbourg, Strasbourg, France.
Transbound Emerg Dis. 2018 Feb;65(1):e94-e103. doi: 10.1111/tbed.12686. Epub 2017 Aug 15.
Following the emergence of the Schmallenberg virus (SBV) in 2011 in Germany and its rapid spread in Europe, Culicoides (Diptera: Ceratopogonidae) collected through the French surveillance network were analysed in order to record the presence of virus genome into species diversity collected, to assess the minimum infectious rates (MIR) and the virus circulation dynamics in Culicoides populations. Two vector activity periods were selected (2011, August to October, 53 sites and 2012, June to October, 35 sites) corresponding to 704 night collections. A total of 29,285 individual midges covering at least 50 species were tested either in pools of maximum 50 females or individually (for Culicoides obsoletus/Culicoides scoticus) using real-time RT-PCR. Nine species were found SBV positive (C. obsoletus, C. scoticus, Culicoides chiopterus, Culicoides dewulfi, Culicoides imicola, Culicoides pulicaris, Culicoides newsteadi, Culicoides lupicaris and Culicoides nubeculosus) with overall MIR ranging from 0.2% to 4.2%. While the Culicoides nubeculosus laboratory strain is generally considered to have only low vector competence for viruses, interestingly, field-caught C. nubeculosus specimens were found positive twice for SBV. The first SBV-positive pool was recorded in August 2011 in north-eastern France, dating the virus circulation in France 5 months earlier than the first recorded congenital malformations and 2 months earlier than the former recorded date based on retrospective serological data. The MIR were maximum in October 2011, and in July 2012 according to dates of virus arrival in the studied areas. Moreover, our study also showed that virus circulation could be locally intense with infection rate (IR) reaching up to 16% for C. obsoletus/C. scoticus in July 2012 in one site of western France. This retrospective study demonstrates the importance of large-scale analysis to describe the spatio-temporal dynamics of virus circulation.
2011 年德国出现沙米伦贝格病毒（SBV）后，该病毒迅速在欧洲传播，为了记录病毒基因组在收集的物种多样性中的存在，评估最小感染率（MIR）和库蠓种群中的病毒循环动态，对通过法国监测网络收集的库蠓进行了分析。选择了两个向量活动期（2011 年 8 月至 10 月，53 个地点和 2012 年 6 月至 10 月，35 个地点），对应于 704 个夜间收集。共测试了至少 50 种的 29285 只中蠓，这些中蠓要么在最多 50 只雌性的池中进行测试，要么单独进行测试（对于 C. obsoletus/Culicoides scoticus），使用实时 RT-PCR。发现 9 种 SBV 呈阳性（C. obsoletus、C. scoticus、Culicoides chiopterus、Culicoides dewulfi、Culicoides imicola、Culicoides pulicaris、Culicoides newsteadi、Culicoides lupicaris 和 Culicoides nubeculosus），总体 MIR 范围为 0.2%至 4.2%。虽然通常认为库蠓实验室株对病毒的媒介能力较低，但有趣的是，在野外捕获的 C. nubeculosus 标本两次被发现 SBV 呈阳性。第一个 SBV 阳性池于 2011 年 8 月在法国东北部记录，这比首次记录的先天性畸形早了 5 个月，比基于回顾性血清学数据的前一个记录日期早了 2 个月。2011 年 10 月和 2012 年 7 月 MIR 最高，这是根据研究区域病毒到达的日期得出的。此外，我们的研究还表明，病毒循环可能在局部地区非常强烈，感染率（IR）在 2012 年 7 月可达 16%，这是在法国西部一个地点的 C. obsoletus/C. scoticus。这项回顾性研究表明，大规模分析对于描述病毒循环的时空动态非常重要。
