WHO, ANSES, RICET, and the Ministry of Health and Consumption.

Invasion of new territories by insect vector species that can transmit pathogens is one of the most important threats for human health. The spread of the mosquito Aedes albopictus in Europe is emblematic, because of its major role in the emergence and transmission of arboviruses such as dengue or chikungunya. Here, we modeled the spread of this mosquito species in France through a statistical framework taking advantage of a long-term surveillance dataset going back to the first observation of Ae. albopictus in the Metropolitan area. After validating the model, we show that human activities are especially important for mosquito dispersion while land use is a major factor for mosquito establishment. More importantly, we show that Ae. albopictus invasion is accelerating through time in this area, resulting in a geographic range extending further and further year after year. We also show that sporadic “jump” of Ae. albopictus in a new location far from the colonized area did not succeed in starting a new invasion front so far. Finally, we discuss on a potential adaptation to cooler climate and the risk of invasion into Northern latitudes.

Since its emergence in Yap Island in 2007, Zika virus (ZIKV) has affected all continents except Europe. Despite the hundreds of cases imported to European countries from ZIKV-infested regions, no local cases have been reported in localities where the ZIKV-competent mosquito Aedes albopictus is well established. Here we analysed the vector competence of European Aedes (aegypti and albopictus) mosquitoes to different genotypes of ZIKV. We demonstrate that Ae. albopictus from France was less susceptible to the Asian ZIKV than to the African ZIKV. Critically we show that effective crossing of anatomical barriers (midgut and salivary glands) after an infectious blood meal depends on a viral load threshold to trigger: (i) viral dissemination from the midgut to infect mosquito internal organs and (ii) viral transmission from the saliva to infect a vertebrate host. A viral load in body ≥4800 viral copies triggered dissemination and ≥12,000 viral copies set out transmission. Only 27.3% and 18.2% of Ae. albopictus Montpellier mosquitoes meet respectively these two criteria. Collectively, these compelling results stress the poor ability of Ae. albopictus to sustain a local transmission of ZIKV in Europe and provide a promising tool to evaluate the risk of ZIKV transmission in future outbreaks.

Seven cases of urogenital schistosomiasis occurred in Corsica in 2015 and 2016. The episodes were related to exposure to the same river and involved the same parasite strain as an outbreak with 106 cases in summer 2013. The connection calls for further investigations on the presence of an animal reservoir and the survival of infested snails during winter. However, recontamination of the river from previously infected bathers remains the most likely hypothesis.

Dirofilaria immitis and D. repens are filarioid nematodes of animals and humans, transmitted by the bite of infected mosquitoes. Domestic and wild canids are a major natural host and reservoir for these parasites. In this study, we designed a duplex real-time PCR protocol targeting the mitochondrial cytochrome c oxidase subunit I (COI) gene, detecting both D. immitis and D. repens using two primer pairs and two Dirofilaria-specific hydrolysable probes. The sensitivity and specificity of the primers and probes were tested in both experimental and naturally infected samples. The detection limits of this assay were evaluated using plasmid DNA from D. immitis and D. repens. No cross-reaction was observed when testing this system against DNA from other filarial nematodes. The detection limit of the real-time PCR system was one copy per reaction mixture containing 5μl of template DNA. Field application of the new duplex real-time assay was conducted in Corsica. The prevalence rate of D. immitis was 21.3% (20/94) in dogs. In a locality where most dogs with Dirofilaria spp. infection were found, D. immitis and D. repens were detected in 5% (20/389) and 1.5% (6/389) of the Aedes albopictus population, respectively. These results suggest that this sensitive assay is a powerful tool for monitoring dirofilariosis in endemic or high risk areas.