Instituto de Pesquisas René Rachou, FIOCRUZ, Belo Horizonte, Minas Gerais, Brazil.
Programa de Pós-Graduação em Biologia Celular, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
PLoS Negl Trop Dis. 2021 Nov 2;15(11):e0009839. doi: 10.1371/journal.pntd.0009839. eCollection 2021 Nov.
Dengue virus (DENV) and Zika virus (ZIKV) belong to the same viral family, the Flaviviridae. They cause recurring threats to the public health systems of tropical countries such as Brazil. The primary Brazilian vector of both viruses is the mosquito Aedes aegypti. After the mosquito ingests a blood meal from an infected person, the viruses infect and replicate in the midgut, disseminate to secondary tissues and reach the salivary gland (SG), where they are ready to be transmitted to a vertebrate host. It is thought that the intrinsic discrepancies among mosquitoes could affect their ability to deal with viral infections. This study confirms that the DENV and ZIKV infection patterns of nine Ae. aegypti field populations found in geographically separate health districts of an endemic Brazilian city vary. We analyzed the infection rate, disseminated infection, vector competence, and viral load through quantitative PCR. Mosquitoes were challenged using the membrane-feeding assay technique and were tested seven and fourteen days post-infection (early and late infection phases, respectively). The infection responses varied among the Ae. aegypti populations for both flaviviruses in the two infection phases. There was no similarity between DENV and ZIKV vector competencies or viral loads. According to the results of our study, the risk of viral transmission overtime after infection either increases or remains unaltered in ZIKV infected vectors. However, the risk may increase, decrease, or remain unaltered in DENV-infected vectors depending on the mosquito population. For both flaviviruses, the viral load persisted in the body even until the late infection phase. In contrast to DENV, the ZIKV accumulated in the SG over time in all the mosquito populations. These findings are novel and may help direct the development of control strategies to fight dengue and Zika outbreaks in endemic regions, and provide a warning about the importance of understanding mosquito responses to arboviral infections.
登革热病毒（DENV）和寨卡病毒（ZIKV）属于同一病毒科，黄病毒科。它们对巴西等热带国家的公共卫生系统构成反复威胁。这两种病毒的主要巴西传播媒介是埃及伊蚊。蚊子从受感染的人身上吸食血液后，病毒会在中肠中感染和复制，传播到二级组织并到达唾液腺（SG），在那里它们准备传播给脊椎动物宿主。人们认为蚊子之间的内在差异会影响它们应对病毒感染的能力。这项研究证实，在巴西一个流行城市的地理位置不同的卫生区发现的 9 种埃及伊蚊野外种群的 DENV 和 ZIKV 感染模式存在差异。我们通过定量 PCR 分析了感染率、传播感染、媒介效能和病毒载量。使用膜饲喂测定技术对蚊子进行了挑战，并在感染后 7 天和 14 天（分别为早期和晚期感染阶段）进行了测试。在两个感染阶段，两种黄病毒在埃及伊蚊种群中的感染反应各不相同。在两种感染阶段，DENV 和 ZIKV 的媒介效能或病毒载量均无相似之处。根据我们的研究结果，在感染后的一段时间内，无论是 ZIKV 感染的蚊子还是 DENV 感染的蚊子，病毒传播的风险都会增加或保持不变。但是，根据蚊子种群的不同，DENV 感染的蚊子的风险可能会增加、减少或保持不变。对于这两种黄病毒，病毒载量即使在晚期感染阶段也会持续存在于体内。与 DENV 不同的是，ZIKV 会在所有蚊子种群中随着时间的推移而在 SG 中积累。这些发现是新颖的，可能有助于指导针对流行地区登革热和寨卡爆发的控制策略的制定，并提醒人们了解蚊子对虫媒病毒感染的反应的重要性。
