Chikungunya Virus Transmission Potential by Local <i>Aedes</i> Mosquitoes in the Americas and Europe

<div><p>Background</p><p>Chikungunya virus (CHIKV), mainly transmitted in urban areas by the mosquitoes <i>Aedes aegypti</i> and <i>Aedes albopictus</i>, constitutes a major public health problem. In late 2013, CHIKV emerged on Saint-Martin Island in the Caribbean and spread throughout the region reaching more than 40 countries. Thus far, <i>Ae</i>. <i>aegypti</i> mosquitoes have been implicated as the sole vector in the outbreaks, leading to the hypothesis that CHIKV spread could be limited only to regions where this mosquito species is dominant.</p><p>Methodology/Principal Findings</p><p>We determined the ability of local populations of <i>Ae</i>. <i>aegypti</i> and <i>Ae</i>. <i>albopictus</i> from the Americas and Europe to transmit the CHIKV strain of the Asian genotype isolated from Saint-Martin Island (CHIKV_SM) during the recent epidemic, and an East-Central-South African (ECSA) genotype CHIKV strain isolated from La Réunion Island (CHIKV_LR) as a well-characterized control virus. We also evaluated the effect of temperature on transmission of CHIKV_SM by European <i>Ae</i>. <i>albopictus</i>. We found that (i) <i>Aedes aegypti</i> from Saint-Martin Island transmit CHIKV_SM and CHIKV_LR with similar efficiency, (ii) <i>Ae</i>. <i>aegypti</i> from the Americas display similar transmission efficiency for CHIKV_SM, (iii) American and European populations of the alternative vector species <i>Ae</i>. <i>albopictus</i> were as competent as <i>Ae</i>. <i>aegypti</i> populations with respect to transmission of CHIKV_SM and (iv) exposure of European <i>Ae</i>. <i>albopictus</i> to low temperatures (20°C) significantly reduced the transmission potential for CHIKV_SM.</p><p>Conclusions/Significance</p><p>CHIKV strains belonging to the ECSA genotype could also have initiated local transmission in the new world. Additionally, the ongoing CHIKV outbreak in the Americas could potentially spread throughout <i>Ae</i>. <i>aegypti</i>- and <i>Ae</i>. <i>albopictus</i>-infested regions of the Americas with possible imported cases of CHIKV to <i>Ae</i>. <i>albopictus</i>-infested regions in Europe. Colder temperatures may decrease the local transmission of CHIKV_SM by European <i>Ae</i>. <i>albopictus</i>, potentially explaining the lack of autochthonous transmission of CHIKV_SM in Europe despite the hundreds of imported CHIKV cases returning from the Caribbean.</p>