Demonstration of efficient vertical and venereal transmission of dengue virus type-2 in a genetically diverse laboratory strain of Aedes aegypti.
Demonstration of efficient vertical and venereal transmission of dengue virus type-2 in a genetically diverse laboratory strain of Aedes aegypti.
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DOI：
10.1371/journal.pntd.0006754
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发表时间：
2018-08-01
影响因子：
3.8
通讯作者：
Olson, Ken E
中科院分区：
文献类型：
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作者：
Sanchez-Vargas, Irma;Harrington, Laura C;Olson, Ken E
埃及伊蚊是登革热病毒（DENV；血清型1-4）的主要蚊媒。在流行期间，人-蚊传播循环维持DENV，但在人类感染和媒介丰度最低的情况下，这些病毒如何存活的问题仍然存在。伊蚊可通过两种替代途径在病媒种群中传播登革热病毒：垂直传播和性传播（分别为VT和VNT）。我们在一个遗传多样性实验室（GDLS）菌株中测试了VT和VNT的效率。经口感染DENV2的埃及伊蚊（牙买加1409）。我们通过在C6/36细胞中扩增病毒，然后进行间接免疫荧光测定（IFA），检测了在第一和第二淋养循环（E1和E2）中产生的受感染雌性F1幼虫的病毒包膜(E)抗原。RT-PCR/巢式PCR分析证实IFA阳性样品中存在DENV2 RNA。我们观察了病毒对幼虫和成年雄性后代的VT，以及与通过VT途径获得病毒的雄性交配后病毒对未感染的处女雌虫的VT。在第一个淋养循环后的30个幼虫池（20只/池）中未检测到DENV2，表明病毒在感染后7天传播有限。在感染E2-10d-F1和E2-21-F1后10天和21天接受第二次无病毒血食的E2雌虫，49个幼虫池中有27个（55%）和51个幼虫池中有35个（68.6%）分别检测到DENV2。E2-10d-F1和E2-21d-F1的最小子代感染率分别为1:36和1:29。交配后8天，E2-10d-F1雄虫对未感染GDLS雌虫的VNT率为31.6%（374只中的118只）。在交配前接受血液喂养的感染vnt的雌性蚊子中，有21%的蚊子在头部传播了病毒，这表明病毒有可能再次进入人-蚊子传播周期。这是首次报道由雄性伊蚊传播登革热病毒的VNT。埃及伊蚊和伊蚊首次通过自然感染的雄性进行性传播。我们的研究结果表明，DENV的VT和VNT在本质上可能是流行病间期病毒维持的机制。
Aedes aegypti is the primary mosquito vector of dengue viruses (DENV; serotypes 1-4). Human-mosquito transmission cycles maintain DENV during epidemics but questions remain regarding how these viruses survive when human infections and vector abundance are minimal. Aedes mosquitoes can transmit DENV within the vector population through two alternate routes: vertical and venereal transmission (VT and VNT, respectively). We tested the efficiency of VT and VNT in a genetically diverse laboratory (GDLS) strain of Ae. aegypti orally infected with DENV2 (Jamaica 1409). We examined F1 larvae from infected females generated during the first and second gonotrophic cycles (E1 and E2) for viral envelope (E) antigen by amplifying virus in C6/36 cells and then performing an indirect immunofluorescence assay (IFA). RT-PCR/nested PCR analyses confirmed DENV2 RNA in samples positive by IFA. We observed VT of virus to larvae and adult male progeny and VNT of virus to uninfected virgin females after mating with males that had acquired virus by the VT route. We detected no DENV2 in 30 pools (20 larvae/pool) of F1 larvae following the first gonotrophic cycle, suggesting limited virus dissemination at 7 days post-infection. DENV2 was detected by IFA in 27 of 49 (55%) and 35 of 51 (68.6%) F1 larval pools (20 larvae/pool) from infected E2 females that received a second blood meal without virus at 10 or 21 days post-infection (E2-10d-F1 and E2-21-F1), respectively. The minimum filial infection rates by IFA for E2-10d-F1 and E2-21d-F1 mosquitoes were 1:36 and 1:29, respectively. The VNT rate from E2-10d-F1 males to virgin (uninfected) GDLS females was 31.6% (118 of 374) at 8 days post mating. Twenty one percent of VNT-infected females receiving a blood meal prior to mating had disseminated virus in their heads, suggesting a potential pathway for virus to re-enter the human-mosquito transmission cycle. This is the first report of VNT of DENV by male Ae. aegypti and the first demonstration of sexual transmission in Aedes by naturally infected males. Our results demonstrate the potential for VT and VNT of DENV in nature as mechanisms for virus maintenance during inter-epidemic periods.