Grupo Mosquitos Vetores: Endossimbiontes e Interação Patógeno-Vetor, Instituto René Rachou-Fiocruz, Belo Horizonte, MG, Brazil.
PLoS Negl Trop Dis. 2020 Apr 14;14(4):e0007518. doi: 10.1371/journal.pntd.0007518. eCollection 2020 Apr.
Newly emerging or re-emerging arthropod-borne viruses (arboviruses) are important causes of human morbidity and mortality worldwide. Arboviruses such as Dengue (DENV), Zika (ZIKV), Chikungunya (CHIKV), and West Nile virus (WNV) have undergone extensive geographic expansion in the tropical and sub-tropical regions of the world. In the Americas the main vectors of DENV, ZIKV, and CHIKV are mosquito species adapted to urban environments, namely Aedes aegypti and Aedes albopictus, whereas the main vector of WNV is Culex quinquefasciatus. Given the widespread distribution in the Americas and high permissiveness to arbovirus infection, these mosquito species may play a key role in the epidemiology of other arboviruses normally associated with sylvatic vectors. Here, we test this hypothesis by determining the vector competence of Ae. aegypti, Ae. albopictus, and Cx. quinquefasciatus to Mayaro (MAYV) virus, a sylvatic arbovirus transmitted mainly by Haemagogus janthinomys that has been causing an increasing number of outbreaks in South America, namely in Brazil. Using field mosquitoes from Brazil, female mosquitoes were experimentally infected, and their competence for infection and transmission rates of MAYV was evaluated. We found consistent infection rate for MAYV in Ae. aegypti (57.5%) and Ae. albopictus (61.6%), whereas very low rates were obtained for Cx. quinquefasciatus (2.5%). Concordantly, we observed high potential transmission ability in Ae. aegypti and Ae. albopictus (69.5% and 71.1% respectively), in contrast to Cx. quinquefasciatus, which could not transmit the MAYV. Notably, we found that very low quantities of virus present in the saliva (undetectable by RT-qPCR) were sufficiently virulent to guarantee transmission. Although Ae. aegypti and Ae. albopictus mosquitoes are not the main vectors for MAYV, our studies suggest that these mosquitoes could play a significant role in the transmission of this arbovirus, since both species showed significant vector competence for MAYV (Genotype D), under laboratory conditions.
新出现或再现的节肢动物传播病毒（arboviruses）是全球人类发病率和死亡率的重要原因。登革热（DENV）、寨卡（ZIKV）、基孔肯雅（CHIKV）和西尼罗河病毒（WNV）等 arboviruses 在世界热带和亚热带地区广泛传播。在美洲，DENV、ZIKV 和 CHIKV 的主要传播媒介是适应城市环境的蚊子物种，即埃及伊蚊和白纹伊蚊，而 WNV 的主要传播媒介是库蚊。鉴于这些蚊子在美洲的广泛分布和对 arbovirus 感染的高度易感性，它们可能在其他通常与森林媒介相关的 arboviruses 的流行病学中发挥关键作用。在这里，我们通过确定埃及伊蚊、白纹伊蚊和库蚊对 Mayaro（MAYV）病毒的媒介能力来检验这一假设，Mayaro 病毒是一种主要由 Haemagogus janthinomys 传播的森林 arbovirus，近年来在南美洲（尤其是巴西）引起了越来越多的暴发。使用来自巴西的野外蚊子，对雌性蚊子进行了实验性感染，并评估了它们对 MAYV 的感染和传播率。我们发现 MAYV 在埃及伊蚊（57.5%）和白纹伊蚊（61.6%）中的感染率一致，而库蚊的感染率非常低（2.5%）。一致地，我们观察到埃及伊蚊和白纹伊蚊具有很高的潜在传播能力（分别为 69.5%和 71.1%），而库蚊则不能传播 MAYV。值得注意的是，我们发现唾液中存在的病毒量非常低（无法通过 RT-qPCR 检测到）足以保证传播。尽管埃及伊蚊和白纹伊蚊不是 MAYV 的主要传播媒介，但我们的研究表明，这两种蚊子在实验室条件下对 MAYV（基因型 D）具有显著的媒介能力，因此它们可能在该 arbovirus 的传播中发挥重要作用。
