Correlation between the geographic and genetic distance matrices.

<p>The regression line corresponds to the standard major axis regression between pairwise genetic distances and logarithmic geographic distances with equation: Fst = - 0.1620 + 0.09113·log (geographic distance). The relationship was significant (Mantel test: Z = 16.3746; r = 0.6164; P < 0.001).</p

Phylogenetic tree obtained with a Bayesian inference of concatenated CO1 and ND4 sequence data.

<p>Numbers in parentheses indicate the number of samples belonging to this haplotype. For the Australian sample, only the CO1 sequence was available. Rooting was inferred from DNA sequences of <i>Anopheles pullus</i> and <i>Culex quinquefasciatus</i> but were not represented for clarity</p

Representation of the MtDNA haplotype frequencies within the sample sites.

<p>The left circles indicate the CO1 haplotype frequencies and the right circles the ND4 haplotype frequencies. The arc length of each slice is proportional to the haplotype frequencies (as an example a semicircle represents 15 samples). Haplotype frequencies are indicated in <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0004374#pntd.0004374.s002" target="_blank">S1 Table</a>.</p

Median-joining network obtained with the haplotypes of all samples.

<p>A- Representation for the mtDNA CO1 sequences. B- Representation for mtDNA ND4 sequences. The diameters of grey circles represent the frequency of each haplotype for all individuals. The red number indicates the position of the mutation on the analyzed sequences.</p

Model-based clustering of 270 <i>Ae</i>. <i>aegypti</i> individuals using STRUCTURE software.

<p>Each individual is represented by a single vertical line; sample sites are separated by a black line; the whole sample is divided into K colors representing the number of clusters assumed. The colors show the estimated individual proportions of cluster membership.</p

Release & monitoring of <i>w</i>Mel-infected <i>Ae</i>. <i>aegypti</i> within 12 areas of Port Vila, Vanuatu.

Each release area was divided into a grid with 100 x 100 meter squares. Grid squares lacking mosquito releases were omitted. Release gradient was determined by using GPS coordinates of each release event and assigning the number of wMel-infected mosquitos to a corresponding grid square. Monitoring numbers were determined in the same way. Map produced in QGIS version 3.16.1 using boundaries aggregated from the enumeration area boundaries freely available from the Pacific Data Hub (https://pacificdata.org/data/dataset/2016_vut_phc_admin_boundaries) and OpenMapTiles basemap layer (https://openmaptiles.org/) with CARTO light design (https://carto.com/)). (PNG)</p

<i>w</i>Mel introgression in two areas in South Tarawa, Kiribati.

A) South Tarawa, Kiribati showing the two release areas: Betio (left) and Bairiki (right). B) Introgression of wMel. The line (left axis) represents the percent of Ae. aegypti tested that were infected with wMel Wolbachia, between May 2018 and December 2019. The bars (right axis) indicate the number of Ae. aegypti tested. Data points with less than five screened mosquitos have been omitted. Shaded orange areas indicate wMel mosquito release times. Map produced in QGIS version 3.16.1 using the enumeration area boundaries freely available from the Pacific Data Hub (https://pacificdata.org/data/dataset/2010_kir_phc_admin_boundaries) and OpenMapTiles basemap layer (https://openmaptiles.org/) with CARTO light design (https://carto.com/).</p

Suspected dengue cases notified in Port Vila from January 2016 –January 2022 by (A) hospitalisation status and (B) diagnostic test result.

Blue shading indicates release period for Wolbachia (wMel)-infected Ae. aegypti. Suspected dengue cases without any laboratory diagnostic testing are included in panel A, but excluded from panel B.</p

DENV Prevalence in <i>Wolbachia</i>-infected Mosquitoes.

Pacific Island countries have experienced periodic dengue, chikungunya and Zika outbreaks for decades. The prevention and control of these mosquito-borne diseases rely heavily on control of Aedes aegypti mosquitoes, which in most settings are the primary vector. Introgression of the intracellular bacterium Wolbachia pipientis (wMel strain) into Ae. aegypti populations reduces their vector competence and consequently lowers dengue incidence in the human population. Here we describe successful area-wide deployments of wMel-infected Ae. aegypti in Suva, Lautoka, Nadi (Fiji), Port Vila (Vanuatu) and South Tarawa (Kiribati). With community support, weekly releases of wMel-infected Ae. aegypti mosquitoes for between 2 to 5 months resulted in wMel introgression in nearly all locations. Long term monitoring confirmed a high, self-sustaining prevalence of wMel infecting mosquitoes in almost all deployment areas. Measurement of public health outcomes were disrupted by the Covid19 pandemic but are expected to emerge in the coming years.</div

Insecticide Resistance (IR) Profiles of Release Strains determined by WHO Biosaay.

A) Fiji release strain IR profile. B) Vanuatu release strain IR profile. C) Kiribati release strain IR profile. Each data point is the mean of five biological replicates (± s.d.) using approximately 20 mosquitoes per replicate. (TIFF)</p