Biology subjects

Garros, C.

Publications and source records attributed to Garros, C..

3 recordsLinked to original sources

bioRxiv2025

Aedes albopictus is rapidly invading its climatic niche in France: wider implications for biting nuisance and arbovirus control in Western Europe

The Asian tiger mosquito, Aedes albopictus, is a competent vector of arboviruses, such as dengue. After its introduction into southern Europe, this invasive species has been rapidly spreading as well as causing autochthonous cases of arboviral diseases. Both Ae. albopictus presence and potential to transmit arboviruses are facilitated at warm temperatures, hence global warming is expected to affect their presence in temperate regions. We use a climate- and environmental-driven mechanistic modelling framework to investigate the impact of recent climate change on Ae. albopictus range expansion and its potential to transmit dengue in Western Europe. We simulate climatic suitability, adult density and dengue transmission risk which we compare with a large ensemble of entomological and epidemiological observations over the past 20 years. Most importantly, we analyze a novel spatiotemporal dataset of colonized municipalities in metropolitan France to estimate the spread rate of Ae. albopictus and compare it with model predictions. Lastly, we analyze the sensitivity of entomological and epidemiological risk to changes in temperature, rainfall and human density. Distribution of simulated mosquito populations and dengue transmission risk satisfactorily match entomological and dengue observations for Western Europe (AUC = 0.90 and 0.75 respectively). While lowlands in southern Europe were already climatically suitable for hosting Ae. albopictus around 2010, Western France, together with large populated cities, such as London, Zagreb and Vienna, have become suitable recently. Importantly, the accelerating colonization of Ae. albopictus in France may be approaching the limit of its theoretical climatic niche; future expansion will depend on the climate-driven enlargement of suitable areas. Area at risk of dengue transmission has recently expanded from the Mediterranean coasts over northern Spain and Western France. The sensitivity analysis suggests that climate change may expose medium-sized cities to the highest epidemiological risk; this finding is consistent with recently reported dengue outbreaks in Europe.

ecology↗

bioRxiv2020

Identifying candidate Culicoides spp. (Diptera: Ceratopogonidae) for the study of interactions with Candidatus Cardinium hertigii (Bacteroidetes).

Culicoides biting midges (Diptera: Ceratopogonidae) are disease vectors responsible for the transmission of several viruses of economic and animal health importance. The recent deployment of Wolbachia with pathogen-blocking capacity to control viral disease transmission by mosquitoes has led to a focus on the potential use of endosymbionts to control arboviruses transmitted by other vector species. Previous screens of Culicoides have described the presence of Candidatus Cardinium hertigii (Bacteroidetes). However, the biological impact of this symbiont is yet to be uncovered and awaits a suitable system to study Cardinium-midge interactions. To identify candidate species to investigate these interactions, accurate knowledge of the distribution of the symbiont within Culicoides populations is needed. We used a sensitive nested PCR assay to screen Cardinium infection in 337 individuals of 25 Culicoides species from both Palearctic and Afrotropical regions. Infections were observed in several vector species including C. imicola and the pulicaris complex (C. pulicaris, C. bysta, C. newsteadi and C. punctatus) with prevalence ranging from low and intermediate, to fixation. Infection in C. pulicaris was very rare in comparison to a previous study, and there is evidence the prior record of high prevalence represents a laboratory contamination error. Phylogenetic analysis based on the Gyrase B gene sequence grouped all new isolates within "group C" of the genus, a clade which has to date been exclusively described in Culicoides. Through a comparison of our results with previous screens, we evaluate the suitability of Cardinium-infected species for future work pertaining to the symbiont.

microbiology↗

bioRxiv2020

Cardinium symbiosis as a potential confounder of mtDNA based phylogeographic inference in Culicoides imicola (Diptera: Ceratopogonidae), a vector of veterinary viruses

Culicoides imicola (Diptera: Ceratopogonidae) is an important Afrotropical and Palearctic vector of disease, transmitting viruses of animal health and economic significance. The apparent incursions of C. imicola into mainland Europe via wind-movement events has made it important to trace this species to better predict new areas of arbovirus outbreaks. A widely used method for tracking dispersal patterns of C. imicola employs a phylogeographic approach anchored on the mtDNA marker COI (cytochrome c oxidase subunit I). However, a problem with this approach is that maternally-inherited symbiotic bacteria can alter the frequency of COI mitochondrial haplotypes (mitotypes), masking the true patterns of movement and gene flow. In this study, we investigate possible associations of the symbiont Cardinium with C. imicola mitotype distribution. Haplotype network analysis indicates the concordance of specific mitotypes with Cardinium infection status in C. imicola populations from the Mediterranean basin and South Africa. This observation urges caution on the single usage of the COI marker to determine population structure and movement in C. imicola, and instead suggests the complementary utilisation of additional molecular markers (e.g. microsatellites and nuclear markers).

microbiology↗