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. 2016 Jul 7:6:29564.
doi: 10.1038/srep29564.

Importance of mosquito "quasispecies" in selecting an epidemic arthropod-borne virus

Marie Vazeille  1 , Karima Zouache  1 , Anubis Vega-Rúa  1   2 , Jean-Michel Thiberge  3 , Valérie Caro  3 , André Yébakima  4 , Laurence Mousson  1 , Géraldine Piorkowski  5   6 , Catherine Dauga  7 , Marie-Christine Vaney  8 , Mosè Manni  9 , Giuliano Gasperi  9 , Xavier de Lamballerie  5   6 , Anna-Bella Failloux  1
Affiliations

Importance of mosquito "quasispecies" in selecting an epidemic arthropod-borne virus

Marie Vazeille et al. Sci Rep. .

Abstract

Most arthropod-borne viruses (arboviruses), perpetuated by alternation between a vertebrate host and an insect vector, are likely to emerge through minor genetic changes enabling the virus to adapt to new hosts. In the past decade, chikungunya virus (CHIKV; Alphavirus, Togaviridae) has emerged on La Réunion Island following the selection of a unique substitution in the CHIKV E1 envelope glycoprotein (E1-A226V) of an East-Central-South African (ECSA) genotype conferring a higher transmission rate by the mosquito Aedes albopictus. Assumed to have occurred independently on at least four separate occasions, this evolutionary convergence was suspected to be responsible for CHIKV worldwide expansion. However, assumptions on CHIKV emergence were mainly based on viral genetic changes and the role of the mosquito population quasispecies remained unexplored. Here we show that the nature of the vector population is pivotal in selecting the epidemic CHIKV. We demonstrate using microsatellites mosquito genotyping that Ae. albopictus populations are genetically differentiated, contributing to explain their differential ability to select the E1-226V mutation. Aedes albopictus, newly introduced in Congo coinciding with the first CHIKV outbreak, was not able to select the substitution E1-A226V nor to preferentially transmit a CHIKV clone harboring the E1-226V as did Ae. albopictus from La Réunion.

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Figures

Figure 1
Figure 1. Disseminated infection rates, transmission rates and viral loads of saliva for mosquitoes infected with the two parental strains Congo_2011 and DRC_2000.
(a) Disseminated infection rates, (b) transmission rates and (c) viral loads in saliva detected at 7 dpi for Aedes aegypti and Aedes albopictus from the Congo orally infected with the parental strains Congo_2011 and DRC_2000 provided at a titer of 106.5 pfu/mL in the blood-meal. In brackets, the number of mosquitoes tested.
Figure 2
Figure 2. Experimental design for selecting CHIKV strains by alternate passages and vector competence analysis of samples.
(a) The DRC_2000_HFF was alternatively passaged 10 times between mammalian HFF cells and mosquitoes (Ae. aegypti or Ae. albopictus) to mimic host alternation. Transmission efficiency was estimated after oral infection of mosquitoes. Genetic changes were identified by comparing the consensus sequence obtained with the reference CHIKV S27. Genetic diversity was determined by estimating variants in the viral population by deep sequencing. (b) Disseminated infection rates, (c) transmission rates and (d) viral loads of saliva at 7 dpi for mosquitoes orally infected with DRC_2000_HFF, and the 10 alternate passages between HFF cells and mosquitoes, provided at a titer of 106.5 pfu/mL in the blood-meal. Error bars show the confidence intervals (95%). Significant p values are indicated by an asterix. In brackets, the number of mosquitoes tested.
Figure 3
Figure 3. The biological clone E1-V IOL lineage is better transmitted by Ae. albopictus from La Réunion but not by Ae. albopictus from Congo.
Both strains of Ae. albopictus (Congo and La Réunion) and Ae. aegypti from Congo were exposed to an infectious blood-meal containing an individual clone or both clones provided at equal titers. Saliva collected at 7 dpi were inoculated on Vero cells. (a) For mosquitoes infected with one viral clone, the percentage of infectious saliva was determined. (b) For mosquitoes infected with both viral clones, saliva were collected and inoculated on Vero cells. Then, lytic plaques were collected for RNA extraction and sequencing to define the identity of the amino-acid at the position E1-226. Proportion of E1-V among clones examined in saliva was estimated at 7 dpi for mosquitoes blood-fed with E1-A and E1-V provided at equal proportions. Error bars show the confidence intervals (95%).
Figure 4
Figure 4. Genetic differentiation of Aedes albopictus populations.
(a) Map showing the four E1-A226V substitution emergence events in La Réunion Island, India, Cameroon and Gabon and spreading of CHIKV ECSA lineage correlated with the presence of Ae. albopictus. Date of introduction or first description of Ae. albopictus in the country is indicated. (b) Neighbor-joining cluster analysis (unrooted) based on Cavalli-Sforza and Edwards’s chord distance. Apparent root (CAL from India) is for visual purposes only. Numbers indicate bootstrap values above 65%. Genotyping included DNA extraction from 30 mosquitoes (15 males and 15 females), PCR amplification of 11 microsatellites and sequencing of fragments for scoring haplotypes. A dendrogram based on microsatellite Cavalli-Sforza & Edwards’s genetic distance clustering by the NJ method was constructed using 16 Ae. albopictus populations: ALPROV, Saint-Denis, La Réunion; BL, Bar-sur-Loup, France; CAL, Calcutta, India; CONG, Brazzaville, Congo; JRB, Jurujuba, Brazil; MAN, Manaus, Brazil; MFILOU, Brazzaville, Congo; MIA, Misiones, Argentina; MXA, Tapachula, Mexico; PNA, Colon, Panama; PNM, Parnamirim, Brazil; SAN, Santos, Brazil; STANDRE, Saint-André, La Réunion; STR, Santarém, Brazil; TYS, Tyson, United States; VRB, Florida, United states. F1 mosquitoes were used except for the lab colony CAL. The map was modified using PowerPoint from http://www.powerpointslides.net/powerpointgraphics/powerpointmaps.html using a map previously published in.
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References

    1. Wang E. et al.. Evolutionary relationships of endemic/epidemic and sylvatic dengue viruses. J Virol 74, 3227–3234 (2000). - PMC - PubMed
    1. Moncayo A. C. et al.. Dengue emergence and adaptation to peridomestic mosquitoes. Emerg Infect Dis 10, 1790–1796, 10.3201/eid1010.030846 (2004). - DOI - PMC - PubMed
    1. Anishchenko M. et al.. Venezuelan encephalitis emergence mediated by a phylogenetically predicted viral mutation. Proc Natl Acad Sci USA 103, 4994–4999, 10.1073/pnas.0509961103 (2006). - DOI - PMC - PubMed
    1. Schuffenecker I. et al.. Genome microevolution of chikungunya viruses causing the Indian Ocean outbreak. PLoS Med 3, e263, 10.1371/journal.pmed.0030263 (2006). - DOI - PMC - PubMed
    1. Juliano S. A. & Lounibos L. P. Ecology of invasive mosquitoes: effects on resident species and on human health. Ecol Lett 8, 558–574, 10.1111/j.1461-0248.2005.00755 (2005). - DOI - PMC - PubMed

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