State Key Laboratory of Pathogen and Biosecurity, Beijing 100071, China; Jiangxi International Travel Healthcare Center, Nanchang 330002, China.
Jiangxi Provincial Center for Disease Control and Prevention, Nanchang 330002, China.
Infect Genet Evol. 2024 Sep;123:105627. doi: 10.1016/j.meegid.2024.105627. Epub 2024 Jun 21.
Hainan Island and the Leizhou Peninsula, the southernmost part of mainland China, are areas where Aedes aegypti and Ae. albopictus are sympatric and are also high-incidence areas of dengue outbreaks in China. Many studies have suggested that Aedes endogenous viral components (EVEs) are enriched in piRNA clusters which can silence incoming viral genomes. Investigation the EVEs present in the piRNA clusters associated with viral infection of Aedes mosquitoes in these regions may provide a theoretical basis for novel transmission-blocking vector control strategies.
In this study, specific primers for endogenous Flaviviridae elements (EFVEs) and endogenous Rhabdoviridae elements (ERVEs) were used to detect the distribution of Zika virus infection associated EVEs in the genomes of individuals of the two Aedes mosquitoes. Genetic diversity of EVEs with a high detection rate was also analyzed.
The results showed that many EVEs associated with Zika virus infection were detected in both Aedes species, with the detection rates were 47.68% to 100% in Ae. aegypti and 36.15% to 92.31% in sympatric Ae. albopictus populations. EVEs detection rates in another 17 Ae. albopictus populations ranged from 29.39% to 89.85%. Genetic diversity analyses of the four EVEs (AaFlavi53, AaRha61, AaRha91 and AaRha100) of Ae. aegypti showed that each had high haplotype diversity and low nucleotide diversity. The number of haplotypes in AaFlavi53 was 8, with the dominant haplotype being Hap_1 and the other 7 haplotypes being further mutated from Hap_1 in a lineage direction. In contrast, the haplotype diversity of the other three ERVEs (AaRha61, AaRha91 and AaRha100) was more diverse and richer, with the haplotype numbers were 9, 15 and 19 respectively. In addition, these EVEs all showed inconsistent patterns of both population differentiation and dispersal compared to neutral evolutionary genes such as the Mitochondrial COI gene.
The EFVEs and ERVEs tested were present at high frequencies in the field Aedes mosquito populations. The haplotype diversity of the EFVE AaFlavi53 was relatively lower and the three ERVEs (AaRha61, AaRha91, AaRha100) were higher. None of the four EVEs could be indicative of the genetic diversity of the Ae. aegypti population. This study provided theoretical support for the use of EVEs to block arbovirus transmission, but further research is needed into the mechanisms by which these EVEs are antiviral to Aedes mosquitoes.
海南岛和雷州半岛是中国大陆最南端的地区，是埃及伊蚊和白纹伊蚊共生的地区，也是中国登革热爆发的高发地区。许多研究表明，埃及伊蚊内源性病毒成分（EVEs）在富含 piRNA 簇的地方富集，这些 piRNA 簇可以沉默传入的病毒基因组。研究这些地区与登革热病毒感染相关的埃及伊蚊中存在的 piRNA 簇中的 EVEs，可能为新型传播阻断的蚊虫控制策略提供理论依据。
在这项研究中，使用了内源性黄病毒元件（EFVEs）和内源性弹状病毒元件（ERVEs）的特异性引物，来检测两种埃及伊蚊个体中与寨卡病毒感染相关的 EVEs 的分布。还分析了高检出率 EVEs 的遗传多样性。
结果表明，在两种埃及伊蚊中都检测到了许多与寨卡病毒感染相关的 EVEs，埃及伊蚊的检出率为 47.68%100%，共生的白纹伊蚊种群的检出率为 36.15%92.31%。在另外 17 个白纹伊蚊种群中，EVEs 的检出率在 29.39%~89.85%之间。对埃及伊蚊的 4 个 EVEs（AaFlavi53、AaRha61、AaRha91 和 AaRha100）的遗传多样性分析表明，每个 EVEs 都具有高度的单倍型多样性和低度的核苷酸多样性。AaFlavi53 的单倍型数量为 8 个，优势单倍型为 Hap_1，其他 7 个单倍型是在谱系方向上由 Hap_1 进一步突变而来。相比之下，其他三个 ERVEs（AaRha61、AaRha91 和 AaRha100）的单倍型多样性更加多样和丰富，单倍型数量分别为 9、15 和 19。此外，与线粒体 COI 基因等中性进化基因相比，这些 EVEs 的种群分化和扩散模式都不一致。
在所测试的现场埃及伊蚊种群中，EFVEs 和 ERVEs 的检出率都很高。EFVE AaFlavi53 的单倍型多样性相对较低，而三个 ERVEs（AaRha61、AaRha91、AaRha100）的单倍型多样性较高。这四个 EVEs 都不能指示埃及伊蚊种群的遗传多样性。本研究为利用 EVEs 阻断虫媒病毒传播提供了理论支持，但需要进一步研究这些 EVEs 对埃及伊蚊抗病毒的机制。
