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Background Elimination of hepatitis C virus (HCV) among people who use drugs (PWUD) remains a challenge even in countries in which HCV care is provided free of cost. We assessed whether an innovative community-based, respondent-driven sampling (RDS) survey, coupled with HCV screening and immediate treatment, could be efficient to detect and cure current PWUD with chronic HCV in a large city of Southern France. Methods At a community site with peers, PWUD (cannabis not included) were enrolled after confirmation by a urine drug test. Participants were then screened for hepatitis B virus, HCV, and human immunodeficiency virus and benefited from onsite HCV treatment evaluation and prescription. Peer support was provided during treatment, and a systematic visit was scheduled 12 weeks after the end of treatment. The cost of the intervention was estimated. Results Five hundred fifty-four participants were enrolled. Most were male (78.8%) with a median age of 39 years (interquartile range, 33–46). Cocaine (73.1%) and heroine (46.8%) were the main drugs consumed. Overall, 32.6% of PWUD (N = 181) were HCV seropositive, 49 (27.1%) of which had detectable HCV ribonucleic acid and were thus eligible for treatment. Ten of these patients had severe fibrosis. Hepatitis C virus treatment was initiated for 37 (75.5%) patients, 30 (81.1%) of whom completed their treatment and 27 (73.0%) achieved sustained viral response at week 12. The total cost was 161 euros € per screened patient and 1816€ per patient needing treatment. Conclusions A community-based RDS survey approach, involving peers, proved efficient and cost-effective to reach and cure PWUD for HCV. This innovative strategy could be key for the final step of HCV elimination. Clinical trial registration. ClinicalTrials.gov, NCT04008927.

Insect pheromone traps are becoming an increasingly important tool in biosecurity and pest surveillance, alerting managers to the presence of unwanted organisms. To expand the role of these traps beyond their present sentinel role, it is necessary to develop reliable operational models of local insect dispersal. Following the detection of an insect incursion using a pheromone trap, such models could simulate the dispersal of the insect from its emergence site to the point of detection, enabling biosecurity managers to estimate the most likely proximal source of the incursion. An individual-based moth movement model was developed to simulate observed patterns of moth movement in response to the presence or absence of a pheromone. Using parameters derived from a genetic algorithm, it was possible to fit a model based on the three behavioural components (upwind, upwind with zigzags and casting) described in insect anemotaxis theory to a subset of observed movement patterns (0–135° to the wind), but not to the whole spectrum of movement patterns. It appears that current insect anemotaxis theory is missing a downwind flight component. Whilst the frequency of downwind movements is small; their ground speed could lead to significant downwind displacement, having a disproportionately strong influence on a moth movement model, and hence projections of the likely source or target locations.

International audience; Modelling moth dispersal in relation to wind direction and strength could greatly enhance the role of pheromone traps in biosecurity and pest management applications. Anemotaxis theory, which describes moth behaviour in the presence of a pheromone plume and is used as a framework for such models. Currently, however, that theory includes only three components: upwind, zigzagging, and sideways casting behaviour. We test anemotaxis theory by analysing the data from a series of mark– release–recapture experiments where the wind direction was known and the insects were trapped using an irregular grid of pheromone traps. The trapping results provide evidence of a downwind component to the flight patterns of the released insects. This active or passive downwind dispersal is likely to be an appetitive behaviour, occurring prior to the elicitation of pheromone-oriented flight patterns (pheromone anemotaxis). Given the potential for significant displacement during down-wind dispersal, this component will have impact on final trap captures and should be considered when constructing moth dispersal models.

The enemy release hypothesis posits that the initial success of invasive species depends on the scarcity and poor adaptation of native natural enemies such as predators and parasitoids. As for parasitoids, invading hosts are first attacked at low rates by a species-poor complex of mainly generalist species. Over the years, however, parasitoid richness may increase either because the invading host continuously encounters new parasitoid species during its spread (geographic spread-hypothesis) or because local parasitoids need different periods of time to adapt to the novel host (adjustment-hypothesis). Both scenarios should result in a continuous increase of parasitoid richness over time. In this study, we reconstructed the development of the hymenopteran parasitoid complex of the invasive leafminer Cameraria ohridella (Lepidoptera, Gracillariidae). Our results show that the overall parasitism rate increases as a function of host residence time as well as geographic and climatic factors, altogether reflecting the historic spread of C. ohridella. The same variables also explain the individual parasitism rates of several species in the parasitoid complex, but fail to explain the abundance of others. Evidence supporting the “geographic spread-hypothesis” was found in the parasitism pattern of Cirrospilus talitzkii (Hymenoptera, Eulophidae), while that of Pediobius saulius, another eulophid, indicated an increase of parasitism rates by behavioral, phenological or biological adjustments. Compared to fully integrated host-parasitoid associations, however, parasitism rates of C. ohridella are still very low. In addition, the parasitoid complex lacks specialists, provided that the species determined are valid and not complexes of cryptic (and presumably more specialized) species. Probably, the adjustment of specialist parasitoids requires more than a few decades, particularly to invaders which establish in ecological niches free of native hosts, thus eliminating any possibility of recruitment of pre-adapted parasitoids.

Summary 1 Biological invasions have an anthropogenic origin, and although many species are able to spread on their own within the newly invaded area, long-distance dispersal events shown to accelerate rates of spread are frequently associated with human activities. In a previous study, the performances of several invasion models of the spread of the horse chestnut leafminer Cameraria ohridella in Germany were compared, demonstrating that the best model in qualitative and quantitative terms was a stratified dispersal model taking into account the effect of human population density on the probability of long-distance dispersal events. 2 Similar data were collected in France over 4 years (2000–2004, 5274 observation points). These data were used to assess the performance of the best-fit models from Germany using the original parameters and to model the spread of the leafminer in France. 3 The stratified dispersal model accounting for variations in human population density developed in Germany, predicted the invasion of France with a similar level of predictive power as in the area where it was developed. This suggests that an equivalent level of predictability can be expected in a newly invaded country with similar environmental conditions. 4 We applied the model to forecast the future invasion dynamics in the UK from 2005 to 2008, based on the first observations of Cameraria in the country in 2002–2004. Predictions are discussed in the light of different prevailing environmental conditions. 5 Synthesis and application. The model and predictions developed in this study provide one of the few examples of an a priori model of invasion in a newly invaded country, and provide a simple modelling framework that can be used to explore the spread of other invading organisms. In the case of Cameraria, little can be done to prevent or slow its spread but our model, by predicting changes in distribution and rates of spread, provides fore-warning of where and when damaging pest populations are likely to appear.

The leafminer Cameraria ohridella Deschka & Dimic is an invasive pest of horse chestnut, Aesculus hippocastanum L., trees that has spread rapidly across Europe over the past 19 yr. It was recently reported in the United Kingdom, Denmark, and the Ukraine, and this spread is expected to continue through the Scandinavian countries until the northern limit of the host tree distribution is reached. The presence of the species is generally reported first in the cities, either as consequence of human-related transportation or because of the higher number of host trees in these areas. As a consequence, detailed studies of the spread of this pest through rural areas have not yet been carried out. We have monitored the spread of the moth at the fringe of its known distribution in eastern France during the period 2001–2003. The population was estimated by observing the damage caused by the pest and by establishing a network of pheromone traps. Pheromone traps were set up to measure two generations in 2001 and 2002, whereas the spatial pattern of the spread of the species measured by damage assessment was followed for each generation between 2001 and 2003 (nine generations). Spatial and temporal patterns in the population estimates made using these two methods were compared. We found that estimates made from damage assessment correlated with log-transformed estimates from pheromone trap catches, suggesting that both techniques can be used to monitor the spread of this pest. Over the period 2001–2003, the spread rate ranged from 17.0 to 37.9 km/yr, depending on the population threshold and method used.

International audience; We modelled the ecoclimatic niche of Culicoides imicola, a major arthropod vector of midge-borne viral pathogens affecting ruminants and equids, at fine scale and on a global extent, so as to provide insight into current and future risks of disease epizootics, and increase current knowledge of the species' ecology. Based on the known distribution and ecology of C. imicola, the species' response to monthly climatic conditions was characterised using CLIMEX with 109 spatial resolution climatic datasets. The species' climatic niche was projected worldwide and under future climatic scenarios. The validated model highlights the role of irrigation in supporting the occurrence of C. imicola in arid regions. In Europe, the modelled potential distribution of C. imicola extended further West than its reported distribution, raising questions regarding ongoing process of colonization and non-climatic habitat factors. The CLIMEX model highlighted similar ecological niches for C. imicola and the Australasian C. brevitarsis raising questions on biogeography and biosecurity. Under the climate change scenarios considered, its' modelled potential distribution could expand northward in the Northern hemisphere, whereas in Africa its range may contract in the future. The biosecurity risks from bluetongue and African horse sickness viruses need to be re-evaluated in regions where the vector's niche is suitable. Under a warmer climate, the risk of vector-borne epizootic pathogens such as bluetongue and African horse sickness viruses are likely to increase as the climate suitability for C.imicola shifts poleward, especially in Western Europe.

KINDL J., KALINOVA B., FREISE J., HEITLAND W., AUGUSTIN S., GUICHARD S., AVTZIS N., SVATOS A. (2002): Monitoring the population dynamics of the horse chestnut leafminer Cameraria ohridella with a synthetic pheromone in Europe. Plant Protect. Sci., 38: 131–138. A monitoring system for Cameraria ohridella males based on a synthetic sex pheromone was tested in the Czech Republic, Germany, France and Greece. From the obtained data on the insect phenology we concluded that in Central Europe C. ohridella typically has three generations per year. The pheromone monitoring can be used to detect the pest when it appears in uninfeste d areas and is also suitable to determine population densities.

Introduction : repérer et intervenir sur la consommation de cannabis des jeunes représente un enjeu pour le médecin généraliste, qui a une place centrale dans leur santé. Néanmoins Ils lui confient peu leurs problèmes intimes, et n'abordent pas spontanément leurs usages de cannabis. Objectif : nous avons étudié les déterminants qui aident les jeunes à discuter de leurs consommations de cannabis avec un médecin généraliste. Méthode : nous avons réalisé une étude qualitative par entretiens semi-dirigés auprès de jeunes consommateurs réguliers de cannabis de 15 à 25 ans, résidant en Hérault. Résultats : vingt personnes ont été inclues. Les jeunes consommateurs consulteraient principalement pour une aide au sevrage, recherchant un médecin qui les soutienne, ouvre le dialogue et approfondisse leur demande initiale. Ils attendent un regard spécialisé sur leur santé, une médiation avec leurs parents et une orientation. Les jeunes patients n'aborderaient pas d'eux-mêmes le sujet du cannabis, mais se disent ouverts à la discussion avec un médecin compétent et impliqué. Le rappel de confidentialité, le cadre individuel de consultation, et le temps dédié à l'échange, sont des facteurs facilitant la discussion, de même que l'attitude empathique et sans jugement du médecin. Conclusion : les jeunes patients sont prêts à se confier à un médecin généraliste sur leur consommation de cannabis, si celui-ci ouvre la discussion et adopte une attitude d'écoute adéquate. L'acronyme « CANNABIS » regroupant nos principaux résultats serait intéressant à évaluer avec des généralistes prêts à l'appliquer, pour devenir éventuellement un outil d'aide à l'abord du cannabis avec un jeune patient.