Chikungunya virus vector competency of Brazilian and Florida mosquito vectors

Chikungunya virus is a vector-borne alphavirus transmitted by the bites of infected female Ae. aegypti and Ae. albopictus. In Brazil between 2014 and 2016 almost 320 thousand autochthonous human cases were reported and in Florida numerous imported CHIKV viremic cases (> 3,800) demonstrate the potential high risk to establishment of local transmission. In the present study, we carried out a series of experiments to determine the viral dissemination and transmission rates of different Brazilian and Florida populations of Ae. aegypti and Ae. albopictus at 2, 5, and 13 days post-infection for the emergent Asian genotype of CHIKV. Our results show that all tested populations of Ae. aegypti and Ae. albopictus have a high proportion (> 0.80) of individuals with disseminated infection as early as 2 days-post exposure. We found no significant treatment effects of mosquito population origin effects on viral dissemination rates. Transmission rates had a heterogeneous pattern, with US Ae. aegypti and Brazilian Ae. albopictus having the highest proportion of individuals with successful infection (respectively 0.50 and 0.82 as early as 2 days-post infection). Model results found significant effects of population origin, population origin x species, population origin x days post-infection and population origin x species x days post infection.基孔肯雅病毒（Chikungunya virus, CHIKV）是一类经虫媒传播的甲病毒，通过受感染的雌性埃及伊蚊（Aedes aegypti，简称Ae. aegypti）与白纹伊蚊（Aedes albopictus，简称Ae. albopictus）叮咬实现传播。2014至2016年间，巴西累计报告近32万例本土人间感染病例；而佛罗里达州发现的大量输入性基孔肯雅病毒血症病例（超3800例），充分凸显了当地存在本地病毒传播定植的高风险。本研究开展了一系列实验，旨在明确针对新兴亚洲基因型基孔肯雅病毒，不同巴西及佛罗里达种群的埃及伊蚊、白纹伊蚊在感染后2、5、13天时的病毒播散率与传播效率。研究结果显示，所有受试的埃及伊蚊与白纹伊蚊种群，在暴露后2天即可检出高比例（＞0.80）的个体发生播散性感染。本研究未观察到蚊虫种群来源对病毒播散率存在显著影响。传播率则呈现异质性分布特征：美国埃及伊蚊种群与巴西白纹伊蚊种群的成功感染个体比例最高，在感染后2天时即可分别达到0.50与0.82。模型分析结果显示，种群来源、种群来源×物种、种群来源×感染后天数以及种群来源×物种×感染后天数均存在显著效应。