Institut de Recerca i Tecnologia Agroalimentàries (IRTA), Centre de Recerca en Sanitat Animal (CReSA), Campus de la Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès), 08193, Barcelona, Spain.
Servei de Control de Mosquits, Consell Comarcal del Baix Llobregat, Barcelona, Spain.
Parasit Vectors. 2019 Jul 25;12(1):363. doi: 10.1186/s13071-019-3620-7.
Aedes caspius (Pallas, 1771) is a floodwater mosquito species widely distributed in the Western Palaearctic. As an anthropophilic species, its role as an arbovirus vector may be the key for understanding the transmission cycle of certain diseases in Europe such as Zika virus (ZIKV). Concerning vector competence for ZIKV, studies related to Ae. caspius are still scarce. ZIKV is an arbovirus that has provoked a widespread epidemic in the Pacific region (2007-2013) and in the Americas (2015-2016). ZIKV is associated with serious neurological injuries (e.g. microcephaly) and Guillain-Barré syndrome. Due to the ZIKV epidemics in the American continent, some viraemic travellers coming from endemic countries have been reported in Europe. More knowledge is therefore required to define the susceptibility of autochthonous mosquito species such as Ae. caspius for ZIKV in order to improve arbovirus surveillance and control programmes. In the present study, the vector competence of a European population of Ae. caspius was evaluated for two ZIKV lineages, the Suriname ZIKV strain (Asian lineage) and the MR766 ZIKV strain (African I lineage). Females were tested at 7, 14 and 21 days post-exposure (dpe) to infectious blood meals. An Ae. aegypti PAEA strain was used as a positive control.
Aedes caspius presented low susceptibility to ZIKV infection and the virus was only detected by RT-qPCR in body samples. Low viral loads were detected for the MR766 strain at 7 dpe and for the Suriname strain at 14 and 21 dpe. Aedes caspius was unable to produce a disseminated infection and virus transmission at any of the tested time points. Using Ae. aegypti PAEA strain, infection, dissemination and transmission rates were calculated for the Suriname ZIKV strain (Asian lineage) at each time point. For the MR766 ZIKV strain (African I lineage), while only infection rates were estimated at each time point, no dissemination or transmission were detected in either species.
The results of the present study reveal that the tested Ae. caspius population has a strong midgut escape barrier that limits the dissemination or transmission of the virus. As such, it seems unlikely that European Ae. caspius mosquitoes could be involved in ZIKV transmission if ZIKV was introduced into Europe. This information may help in designing a better strategy to European surveillance and control programmes for ZIKV.
亚洲虎蚊（Pallas，1771）是一种广泛分布于西古北区的洪水蚊种。作为一种嗜人蚊种，它作为虫媒病毒载体的作用可能是理解欧洲某些疾病（如寨卡病毒（ZIKV））传播周期的关键。关于寨卡病毒的媒介能力，与亚洲虎蚊相关的研究仍然很少。寨卡病毒是一种虫媒病毒，曾在太平洋地区（2007-2013 年）和美洲（2015-2016 年）引发广泛的流行。寨卡病毒与严重的神经损伤（例如小头畸形）和格林-巴利综合征有关。由于美洲大陆的寨卡病毒流行，一些来自流行国家的带病毒旅行者在欧洲被报告。因此，为了改善虫媒病毒监测和控制计划，需要更多的知识来确定像亚洲虎蚊这样的本地蚊种对寨卡病毒的易感性。在本研究中，评估了欧洲亚洲虎蚊种群对两种寨卡病毒谱系（苏里南寨卡病毒株（亚洲谱系）和 MR766 寨卡病毒株（非洲 I 谱系）的媒介能力。在感染性血液餐 7、14 和 21 天后（PE）测试雌性。埃及伊蚊 PAEA 品系被用作阳性对照。
亚洲虎蚊对寨卡病毒感染的易感性较低，仅在尸体样本中通过 RT-qPCR 检测到病毒。在 7 天 PE 时检测到 MR766 株的低病毒载量，在 14 和 21 天 PE 时检测到苏里南株的低病毒载量。亚洲虎蚊无法在任何测试时间点产生弥散感染和病毒传播。使用埃及伊蚊 PAEA 品系，在每个时间点计算了苏里南寨卡病毒株（亚洲谱系）的感染、传播和传播率。对于 MR766 寨卡病毒株（非洲 I 谱系），虽然仅在每个时间点估计了感染率，但在两种物种中均未检测到传播或传播。
本研究结果表明，所测试的亚洲虎蚊种群具有很强的中肠逃逸屏障，限制了病毒的传播或传播。因此，如果寨卡病毒传入欧洲，欧洲的亚洲虎蚊似乎不太可能参与寨卡病毒的传播。这些信息可能有助于制定更好的策略，以对欧洲的寨卡病毒监测和控制计划进行监测。
