Biology subjects

Boulanger, N.

Publications and source records attributed to Boulanger, N..

4 recordsLinked to original sources

bioRxiv2024

Ixodes ricinus bites promote allergic skin inflammation and intestinal tuft and mast cell expansion in mice.

BackgroundTick bites often promote local allergic reactions in the skin and predispose to red meat allergy. The mechanisms involved in these processes are not fully understood. Here we investigated the local changes to the skin and intestine induced by tick bites. MethodsC3H/HEN or Balb/c mice were subjected to either tick bites by Ixodes ricinus (I. ricinus) or mechanical skin injury. Skin or intestine was analyzed a different time point by transcriptomic and histological techniques. ResultsOur results indicate that I. ricinus bites promote epidermal hyperplasia, spongiosis and an accumulation of eosinophils and mast cells in the bitten skin. In addition, I. ricinus bites promote the expression of genes and activate pathways also induced by mechanical skin injury elicited by tape stripping. Remarkably, similar to tape stripping, I. ricinus bites promote an increase in total serum IgE, and intestinal tuft cell and mast cell expansion. ConclusionI. ricinus bites in mice promote cutaneous inflammation that resembles allergic skin inflammation, as well as intestinal changes that could play a role in the predisposition to red meat allergy.

immunology↗

bioRxiv2024

Drivers of Ixodes ricinus population dynamics in Northeast France: a Bayesian modelling approach

Ixodes ricinus is the primary vector for Lyme disease and tick-borne encephalitis across Europe. Despite playing a critical role in disease transmission dynamics, the environmental drivers of its complex life cycle have not been quantified using real-world data. To address this gap, we fitted a unique mechanistic model to a detailed 10-years longitudinal dataset from four sites in Northern France, where I. ricinus is abundant and Lyme disease and tick-borne encephalitis have been reported for decades, within a Bayesian framework. By incorporating key demographic processes and the influence of environmental conditions on these processes, our model estimated oviposition, hatching, and moulting rates across a range of temperature or saturation deficit, as well as questing and vertebrate host contact rates. Notably, moulting peaked at 14.2{degrees}C (95%HDI: 12.5-16.1{degrees}C), substantially lower than commonly suggested by laboratory-based studies, whereas oviposition and hatching peaked at 24.4{degrees}C (95%HDI: 10.9- 27.2{degrees}C) and 24.7{degrees}C (95%HDI: 17.8-27.2{degrees}C), respectively. Furthermore, vertebrate host contact rates significantly varied between the four study sites, with one site presenting up to 2.90 (95%HDI: 2.15-3.86) times higher contact rates than the other three sites. Additionally, we showed the importance of diapause in reproducing the observed seasonal population dynamics. For ticks overwintering through diapause, moulting in spring more accurately matched the predominantly unimodal questing activity patterns observed, compared to moulting in summer. Finally, model projections under several climate change scenarios indicated decreasing tick abundance trends over the next two decades. This study provides a foundation for models of I. ricinus-borne pathogen transmission and can be adapted to other Ixodidae populations of public health significance.

ecology↗

bioRxiv2023

The distribution, phenology, host range and pathogen prevalence of Ixodes ricinus in France: a systematic map and narrative review

The tick Ixodes ricinus is the most important vector species of infectious diseases in European France. Understanding its distribution, phenology, and host species use, along with the distribution and prevalence of associated pathogens at national scales is essential for developing prevention strategies. The aim of this paper is to provide a systematic map and narrative review of the existing knowledge on the eco-epidemiology of I. ricinus in France. Using literature published up to 2020, the present paper provides a distribution map for the species and a summary of environmental factors explaining observed geographical differences in phenology and temporal differences in abundance. The diversity of vertebrate host species used by this tick, along with their degree of infestation when available, are presented and discussed with respect to their potential contribution to the population dynamics of I. ricinus and the circulation of tick-borne zoonotic pathogens. Prevalence data of detected pathogens are summarised in different maps. Results from 187 identified references show that the species is present in most departments, but scarce under Mediterranean climate and in coastal habitats. Its phenology is generally bimodal with variations depending on climate. Abundance seems positively influenced by forest cover and host abundance. Rodents and ruminants are the most studied species groups, but the diversity of sampling protocols (e.g., location, season, exhaustivity of inspection) precluded direct comparisons between species groups. Data on pathogens are patchy, with most studies conducted near research units. Among pathogens, Borrelia burgdorferi sensu lato is the most searched for in ticks and seems more prevalent in north-eastern and central France. The review carried out here has made it possible to highlight the gaps in our knowledge of tick-host-pathogen interactions, their ecology and their distribution, and the need to address these gaps in order to optimize tick and tick-borne diseases prevention and control strategies.

ecology↗

bioRxiv2019

Adiabatic invariants drive rhythmic human motion in variable gravity

Natural human movements are stereotyped. They minimise cost functions that include energy, a natural candidate from mechanical and physiological points of view. In time-changing environments, however, motor strategies are modified since energy is no longer conserved. Adiabatic invariants are relevant observables in such cases, although they have not been investigated in human motor control so far. We fill this gap and show that the theory of adiabatic invariants explains how humans move when gravity varies.

biophysics↗