Infection of a French Population of Aedes albopictus and of Aedes aegypti (Paea Strain) with Zika Virus Reveals Low Transmission Rates to These Vectors’ Saliva

Abstract

Disease caused by the Zika virus (ZIKV) is a public health emergency of international concern. Recent epidemics have emerged in different regions of the world and attest to the ability of the virus to spread wherever its vector, Aedes species mosquitoes, can be found. We have compared the transmission of ZIKV by Ae. aegypti (PAEA strain originating from Tahiti) and by a French population of Ae. albopictus to better assess their competence and the potential risk of the emergence of ZIKV in Europe. We assessed the transmission of ZIKV by Ae. albopictus in temperatures similar to those in Southern France during the summer. Our study shows that the extrinsic incubation period of Ae. aegypti for transmission was shorter than that of Ae. albopictus. Both vectors were able to transmit ZIKV from 10 to 14 days post-infection. Ae. aegypti, however, had a longer transmission period than the French population of Ae. albopictus. Although the salivary glands of both vectors are highly infected, transmission rates of ZIKV to saliva remain relatively low. These observations may suggest that the risk of emergence of ZIKV in Europe could be low.

One-step RT-qPCR assay for ZIKV RNA detection in Aedes aegypti samples: A protocol to study infection & gene expression during ZIKV infection

“…At this time, only five studies [19,21,24,43,47] have detected ZIKV RNA in mosquitoes using SYBR green. However, in three of these studies [24,43,47] commercial kits designed to obtain mostly viral RNA from samples were used, which will not allow for analysis of mosquito gene expression from the same sample.…”

“…In recent studies utilizing RT-qPCR to detect ZIKV RNA in mosquitoes, which mostly analyzed vector competence, it is possible to observe a methodological trend favoring the utilization of hydrolysis probes as a fluorescent label (83% of the papers in literature) and the use of viral RNA extraction kits to obtain the RNA templates (56% of the studies). However the number of studies could actually be higher since some of them do not specify the extraction RNA method used for the experiments [9,14,16,18,19,21,22,23,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51]. Although this approach has demonstrated to be relatively effective in detecting ZIKV RNA, since the isolation of viral RNA is prioritized, it does not permit the study of the gene expression in mosquito genes during viral infection using the same samples.…”

European and tropical Aedes albopictus mosquito populations have similar systemic Zika virus infection dynamics

“…temperature [57][58][59] , rearing or experimental settings) conditions might further complicate comparisons across vector competence studies. An almost unanimous consensus is however prevailing on the existence of a low transmission efficiency 22,24,25,27,43,44,50,60 in the Ae. albopictus/ZIKV couple.…”

One-step RT-qPCR assay for ZIKV RNA detection in Aedes aegypti samples: a protocol to study infection and gene expression during ZIKV infection

“…Molecular detection of ZIKV ribonucleic acid (RNA) in mosquitoes can be challenging due to the limited number of primers and probes published [14][15][16][17][18][19][20][21][22][23][24][25][26][27], as well as the presence of viral genetic material integrated in mosquito genomes [28,29], which can reduce the specificity for RNA detections by quantitative reverse transcription polymerase chain reaction (RT-qPCR) [30]. Most of these ZIKV oligos were optimized in mammalian cells and samples and show often-unresolvable background when used to detect infection in mosquito tissues.…”

“…In recent studies utilizing RT-qPCR to detect ZIKV RNA in mosquitoes, which mostly analyzed vector competence, it is possible to observe a methodological trend favoring the utilization of hydrolysis probes as a fluorescent label (83% of the papers in literature) and the use of viral RNA extraction kits to obtain the RNA templates (56% of the studies). However, the number of studies could actually be higher since some of them do not specify the extraction RNA method used for the experiments [9,14,16,[18][19][20][21][22][23]. Although this approach has demonstrated to be relatively effective in detecting ZIKV RNA, since the isolation of viral RNA is prioritized, it does not permit the study of the gene expression in mosquito genes during viral infection using the same samples.…”