Estimating Spatio-Temporal Dynamics of Aedes Albopictus Dispersal to Guide Control Interventions in Case of Exotic Arboviruses in Temperate Regions

Abstract

The increasing number of exotic arbovirus cases imported in Europe and the 2017 chikungunya outbreak in central/southern Italy highlight the urgency of evidence-based outbreak management plans to predict, prevent or interrupt spreading of these arboviruses to non-endemic countries in temperate regions. We here present the results of three mark-release-recapture experiments conducted in a peri-urban area of North-East Italy to estimate the spatio-temporal dynamics of the dispersal of Aedes albopictus females looking for oviposition sites. The Flight Range of 90% of the mosquito population (FR 90 ) was found to exceed 200 m, consistently with data obtained from a previous study conducted in a highly urbanised area in Rome (Central Italy). Modelling results showed that dispersal can be so rapid that insecticide spraying within a 200m-radius around a potential infected case leaves >10% probability that a potentially infected mosquito escapes the treatment, even if this is carried out after only 2–3 days since the importation of a viremic case. These data provide evidence in favour of an update of guidelines for the control of exotic autochthonous arbovirus transmission in temperate areas and highlight the need of effective surveillance approaches and rapid response to contain the risks associated to imported viremic cases.

A bacterium against the tiger: preliminary evidence of fertility reduction after release of Aedes albopictus males with manipulated Wolbachia infection in an Italian urban area

“…These are ∼ 1.4 km from the treated site, a distance that exceeds the typical Ae. albopictus flight range . Despite the presence of active larval sites in the study areas, no insecticide treatments (against larvae or against adult mosquitoes) were carried out before and during the experiment, in either the treated or control site.…”

Landscape does matter: Disentangling founder effects from natural and human‐aided post‐introduction dispersal during an ongoing biological invasion

“…The context (i.e. ecological characteristics of study sites, objectives of dispersal studies) often impedes the direct comparison of mark–release–capture estimates but recent studies estimated a mean flight range of ~200 m (Marini et al., 2010, 2019). Modelling the potential range expansion of A. albopictus over time using occupancy–detection data, its natural dispersal capabilities and habitat suitability modelling revealed that both natural and human‐aided dispersal are responsible for the rapid expansion in the region of Grenoble since its first introduction in 2012 (Figure 3).…”

“…Probabilities of occurrence values >0.65 were converted into presence values based on the ROC. We modelled the potential natural dispersal of A. albopictus using this binary projection (representing the potential occupancy), yearly presence‐only data and dispersal capabilities estimated in A. albopictus using mark–release–recapture experiments (Marini et al., 2019). This last study estimated 212 m as the mean flight range (i.e.…”

“…four ranges: 2013–2014, 2014–2015, 2015–2016 and 2016–2017), (b) the maximum number of generations (i.e. seven generations considering a generation time of 3 weeks between May/June to October) and (c) the mean flight range per generation (212 m, Marini et al., 2010, 2019), the maximum natural dispersal distance between populations that may be subject to IBD does not exceed 5.9 km. Finding IBD within a geographical range of 5.9 km will thus indicate the influence of natural dispersal, while the absence of IBD above this threshold will be indicative of long‐distance human‐aided dispersal.…”

“…Inferences on dispersal abilities (e.g. Marini, Caputo, Pombi, Tarsitani, & Della Torre, 2010; Marini et al., 2019) combined with spatiotemporal occupancy–detection data make it possible to model the theoretical range expansion of a species over time due to natural dispersal and thus by comparison with new occupancies observed from year to year, to rigorously determine the different modes of dispersal over time and space.…”