Department of Pathogen Biology, Institute of Tropical Medicine, School of Public Health, Southern Medical University, Guangzhou, China.
Infect Dis Poverty. 2022 Jun 4;11(1):62. doi: 10.1186/s40249-022-00990-0.
Zika virus (ZIKV) and dengue virus (DENV) are closely related flaviviruses primarily transmitted by Aedes mosquitoes. Armigeres subalbatus is an emerging and widely distributed mosquito, and ZIKV has been detected and isolated from it. However, it is not clear whether Ar. subalbatus could be a vector for ZIKV and DENV or not. In this study, we investigated the infection and transmission of Ar. subalbatus to ZIKV and DENV.
A line of Ar. subalbatus was isolated from Guangdong, China, and further identified by the mitochondrial cytochrome oxidase subunit 1 (COI) gene. The adults of Ar. subalbatus were fed with blood meal containing ZIKV or DENV-2. At 4, 7, 10, 14, and 21 days post-inoculation (dpi), the infections of ZIKV or DENV-2 in the midguts, ovaries and salivary glands were detected and quantified by RT-PCR and RT-qPCR. To assess the transmissibility, suckling mice were exposed to bites of ZIKV-infected mosquitoes, and ZIKV was detected in brain tissue by RT-qPCR and plaque assays. Furthermore, the larvae of Ar. subalbatus were reared in artificial urine containing ZIKV or DENV-2. The infection rates and viral titers of larvae and adults were analyzed by RT-PCR and RT-qPCR, and the viral distribution in larval tissues was observed by immunohistochemistry. Chi-square test and one-way ANOVA analysis were used for assessing the infection rate and viral titer in varied tissues and different time points, respectively.
Following oral inoculation, ZIKV but not DENV-2 could be detected in Ar. subalbatus midguts at 4 dpi, ovaries at 7 dpi and salivary glands at 10 dpi. The highest infection rate (IR) of ZIKV was 27.8% in midgut at 7 dpi, 9.7% in ovary and 5.6% in salivary gland at 21 dpi. Eight days after being bitten by ZIKV-positive mosquitoes, ZIKV was detected in three brain tissues out of four suckling mice exposed to bites. ZIKV could be detected in the larvae reared in artificial urine contained ZIKV at a high concentration of 10 pfu/ml and various tissues of adults with a low infection rate (0.70-1.35%). ZIKV could be observed in anal papillae and midgut of larvae at 4 dpi under laboratory conditions.
ZIKV but not DENV-2 can infect Ar. subalbatus by blood meal and artificial urine, and the infected mosquitoes can transmit ZIKV to suckling mice by bite. From these findings, we can conclude that the Ar. subalbatus isolated from Guangdong province, China, is a potential vector for ZIKV and should therefore be considered in vector control programs to prevent and control of Zika virus disease.
寨卡病毒（ZIKV）和登革热病毒（DENV）是密切相关的黄病毒，主要通过伊蚊传播。白线斑蚊是一种新兴且分布广泛的蚊子，已从其体内检测到并分离出 ZIKV。然而，白线斑蚊是否可以作为 ZIKV 和 DENV 的传播媒介尚不清楚。在本研究中，我们研究了白线斑蚊对 ZIKV 和 DENV 的感染和传播。
从中国广东分离出白线斑蚊品系，并通过线粒体细胞色素氧化酶亚单位 1（COI）基因进一步鉴定。用含有 ZIKV 或 DENV-2 的血餐喂养白线斑蚊成蚊。在接种后 4、7、10、14 和 21 天（dpi），通过 RT-PCR 和 RT-qPCR 检测和定量检测 ZIKV 或 DENV-2 在中肠、卵巢和唾液腺中的感染情况。为了评估传播能力，用感染 ZIKV 的蚊子叮咬幼鼠，并用 RT-qPCR 和噬斑试验检测幼鼠脑组织中的 ZIKV。此外，在含有 ZIKV 或 DENV-2 的人工尿液中饲养白线斑蚊幼虫。通过 RT-PCR 和 RT-qPCR 分析幼虫和成虫的感染率和病毒滴度，并通过免疫组织化学观察幼虫组织中的病毒分布。卡方检验和单因素方差分析分别用于评估不同组织和不同时间点的感染率和病毒滴度。
经口接种后，白线斑蚊中肠在 4 dpi 时可检测到 ZIKV，但不能检测到 DENV-2，卵巢在 7 dpi 时可检测到 ZIKV，唾液腺在 10 dpi 时可检测到 ZIKV。ZIKV 的最高感染率（IR）为 7 dpi 时中肠的 27.8%，21 dpi 时卵巢的 9.7%和唾液腺的 5.6%。在被感染 ZIKV 的蚊子叮咬 8 天后，在暴露于叮咬的 4 只幼鼠中有 3 只脑组织中检测到 ZIKV。在含有高浓度 10 pfu/ml ZIKV 的人工尿液中饲养的幼虫和感染率较低（0.70-1.35%）的成虫的各个组织中均能检测到 ZIKV。在实验室条件下，4 dpi 时可在幼虫的肛乳突和中肠中观察到 ZIKV。
白线斑蚊可以通过血餐和人工尿液感染 ZIKV，感染的蚊子可以通过叮咬将 ZIKV 传播给幼鼠。从这些发现可以得出结论，从中国广东省分离出的白线斑蚊是 ZIKV 的潜在传播媒介，因此应考虑将其纳入媒介控制计划，以预防和控制寨卡病毒病。
