澳大利亚致倦库蚊和白纹伊蚊对 Zika 病毒流行株的媒介效能。
Vector competence of Australian Aedes aegypti and Aedes albopictus for an epidemic strain of Zika virus.
机构信息
Mosquito Control Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia.
Institute of Health and Biomedical Innovation, and School of Biomedical Sciences Queensland University of Technology, Brisbane, Queensland, Australia.
出版信息
PLoS Negl Trop Dis. 2019 Apr 4;13(4):e0007281. doi: 10.1371/journal.pntd.0007281. eCollection 2019 Apr.
BACKGROUND
Recent epidemics of Zika virus (ZIKV) in the Pacific and the Americas have highlighted its potential as an emerging pathogen of global importance. Both Aedes (Ae.) aegypti and Ae. albopictus are known to transmit ZIKV but variable vector competence has been observed between mosquito populations from different geographical regions and different virus strains. Since Australia remains at risk of ZIKV introduction, we evaluated the vector competence of local Ae. aegypti and Ae. albopictus for a Brazilian epidemic ZIKV strain. In addition, we evaluated the impact of daily temperature fluctuations around a mean of 28°C on ZIKV transmission and extrinsic incubation period.
METHODOLOGY/PRINCIPAL FINDINGS: Mosquitoes were orally challenged with a Brazilian ZIKV strain (8.8 log CCID50/ml) and maintained at either 28°C constant or fluctuating temperature conditions. At 3, 7 and 14 days post-infection (dpi), ZIKV RNA copies were quantified in mosquito bodies, as well as wings and legs, using qRT-PCR, while virus antigen in saliva (a proxy for transmission) was detected using a cell culture ELISA. Despite high body and disseminated infection rates in both vectors, the transmission rates of ZIKV in saliva of Ae. aegypti (50-60%) were significantly higher than in Ae. albopictus (10%) at 14 dpi. Both species supported a high viral load in bodies, with no significant differences between constant and fluctuating temperature conditions. However, a significant difference in viral load in wings and legs between species was observed, with higher titres in Ae. aegypti maintained at constant temperature conditions. For ZIKV transmission to occur in Ae. aegypti, a disseminated virus load threshold of 7.59 log10 copies had to be reached.
CONCLUSIONS/SIGNIFICANCE: Australian Ae. aegypti are better able to transmit a Brazilian ZIKV strain than Ae. albopictus. The results are in agreement with the global consensus that Ae. aegypti is the major vector of ZIKV.
背景
寨卡病毒（ZIKV）在太平洋和美洲的最近流行突显了其作为具有全球重要性的新兴病原体的潜力。已知埃及伊蚊（Aedes aegypti）和白纹伊蚊（Ae. albopictus）都可以传播 ZIKV，但不同地理区域和不同病毒株的蚊种群之间观察到可变的媒介传播能力。由于澳大利亚仍然存在引入 ZIKV 的风险，我们评估了当地埃及伊蚊和白纹伊蚊对巴西流行的 ZIKV 株的媒介传播能力。此外，我们评估了每日温度波动在平均 28°C 左右对 ZIKV 传播和外潜伏期的影响。
方法/主要发现：蚊子通过口服接种巴西 ZIKV 株（8.8 log CCID50/ml），并在 28°C 恒定或波动温度条件下饲养。在感染后 3、7 和 14 天（dpi），使用 qRT-PCR 定量检测蚊子体内、翅膀和腿部的 ZIKV RNA 拷贝数，同时使用细胞培养 ELISA 检测唾液中的病毒抗原（传播的替代物）。尽管两种蚊载体的身体和传播感染率都很高，但在 14 dpi 时，埃及伊蚊唾液中 ZIKV 的传播率（50-60%）明显高于白纹伊蚊（10%）。两种蚊种在体内都支持高病毒载量，恒定和波动温度条件之间没有显著差异。然而，在种间翅膀和腿部的病毒载量之间观察到显著差异，在恒定温度条件下饲养的埃及伊蚊的滴度更高。为了使 ZIKV 在埃及伊蚊中传播，必须达到 7.59 log10 拷贝的传播病毒载量阈值。
结论/意义：澳大利亚埃及伊蚊比白纹伊蚊更能传播巴西 ZIKV 株。结果与全球共识一致，即埃及伊蚊是 ZIKV 的主要传播媒介。
Zotero 插件