Early-life glucocorticoids accelerate lymphocyte count senescence in roe deer.

Immunosenescence corresponds to the progressive decline of immune functions with increasing age. Although it is critical to understand what modulates such a decline, the ecological and physiological drivers of immunosenescence remain poorly understood in the wild. Among them, the level of glucocorticoids (GCs) during early life are good candidates to modulate immunosenescence patterns because these hormones can have long-term consequences on individual physiology.

[Brucellosis in Alpine ibex: 10 years of research and expert assessments].

Brucellosis due to Brucella melitensis affects domestic and wild ruminants, as well as other mammals, including humans. Despite France being officially free of bovine brucellosis since 2005, two human cases of Brucella melitensis infection in the French Alps in 2012 led to the discovery of one infected cattle herd and of one infected population of wild Alpine ibex (Capra ibex). In this review, we present the results of 10 years of research on the epidemiology of brucellosis in this population of Alpine ibex.

Temporal dynamics of antibody level against Lyme disease bacteria in roe deer: Tale of a sentinel?

Changes in the risk of exposure to infectious disease agents can be tracked through variations in antibody prevalence in vertebrate host populations. However, information on the temporal dynamics of the immune status of individuals is critical. If antibody levels persist a long time after exposure to an infectious agent, they could enable the efficient detection of the past circulation of the agent; if they persist only a short time, they could provide snap shots of recent exposure of sampled hosts.

COMPARING ANTIBIOTIC RESISTANCE IN FREE-RANGING VS. CAPTIVE AFRICAN WILD HERBIVORES.

Antimicrobial resistance (AMR) is a critical challenge of the 21st century for public and animal health. The role of host biodiversity and the environment in the evolution and transmission of resistant bacteria between populations and species, and specifically at the wildlife-livestock-human interface, needs to be further investigated. We evaluated the AMR of commensal Escherichia coli in three mammalian herbivore species-impala (Aepyceros melampus), greater kudu (Tragelaphus strepsiceros), and plains zebra (Equus quagga)-targeting populations living under two conditions: captivity (French zoos) and free ranging (natural and private parks in Zimbabwe).

Instability of fecal glucocorticoid metabolites at 4°C: Time to freeze matters.

The use of fecal corticosteroid metabolites (FCMs) has proven to be well suited to evaluate adrenocortical activity, a major component of the stress response, particularly in wildlife. As with any tools, confounding factors and drawbacks must be carefully considered. Among them, sample preservation and storage are of particular importance, as they can affect stability of FCMs and lead to biased results and interpretations.

Age and spatio-temporal variations in food resources modulate stress-immunity relationships in three populations of wild roe deer.

Living in variable and unpredictable environments, organisms face recurrent stressful situations. The endocrine stress response, which includes the secretion of glucocorticoids, helps organisms to cope with these perturbations. Although short-term elevations of glucocorticoid levels are often associated with immediate beneficial consequences for individuals, long-term glucocorticoid elevation can compromise key physiological functions such as immunity.

Variations in immune parameters with age in a wild rodent population and links with survival.

Recent findings suggest that immune functions do not unidirectionally deteriorate with age but that a potentially adaptive remodeling, where functions of the immune system get downregulated while others get upregulated with age could also occur. Scarce in wild populations, longitudinal studies are yet necessary to properly understand the patterns and consequences of age variations of the immune system in the wild. Meanwhile, it is challenging to understand if the observed variations in immune parameters with age are due to changes at the within-individual level or to selective (dis)appearance of individuals with peculiar immune phenotypes.

Covariation between glucocorticoids, behaviour and immunity supports the pace-of-life syndrome hypothesis: an experimental approach.

The biomedical literature has consistently highlighted that long-term elevation of glucocorticoids might impair immune functions. However, patterns are less clear in wild animals. Here, we re-explored the stress-immunity relationship considering the potential effects of behavioural profiles.

Combining seroprevalence and capture-mark-recapture data to estimate the force of infection of brucellosis in a managed population of Alpine ibex.

In wildlife, epidemiological data are often collected using cross-sectional surveys and antibody tests, and seroprevalence is the most common measure used to monitor the transmission dynamics of infectious diseases. On the contrary, the force of infection, a measure of transmission intensity that can help understand epidemiological dynamics and monitor management interventions, remains rarely used. The force of infection can be derived from age-stratified cross-sectional serological data, or from longitudinal data (although less frequently available in wildlife populations).

DNA methylation as a tool to explore ageing in wild roe deer populations.

DNA methylation-based biomarkers of ageing (epigenetic clocks) promise to lead to new insights into evolutionary biology of ageing. Relatively little is known about how the natural environment affects epigenetic ageing effects in wild species. In this study, we took advantage of a unique long-term (>40 years) longitudinal monitoring of individual roe deer (Capreolus capreolus) living in two wild populations (Chizé and Trois-Fontaines, France) facing different ecological contexts, to investigate the relationship between chronological age and levels of DNA methylation (DNAm).

Targeted strategies for the management of wildlife diseases: the case of brucellosis in Alpine ibex.

The management of infectious diseases in wildlife reservoirs is challenging and faces several limitations. However, detailed knowledge of host-pathogen systems often reveal heterogeneity among the hosts' contribution to transmission. Management strategies targeting specific classes of individuals and/or areas, having a particular role in transmission, could be more effective and more acceptable than population-wide interventions.

Interaction Patterns between Wildlife and Cattle Reveal Opportunities for Mycobacteria Transmission in Farms from North-Eastern Atlantic Iberian Peninsula.

Interactions taking place between sympatric wildlife and livestock may contribute to interspecies transmission of the complex or non-tuberculous mycobacteria, leading to the spread of relevant mycobacterioses or to interferences with the diagnosis of tuberculosis. The aim of this study was to characterize the spatiotemporal patterns of interactions between wildlife and cattle in a low bovine tuberculosis prevalence Atlantic region. Camera traps were set during a one-year period in cattle farms with a history of tuberculosis and/or non-tuberculous mycobacterioses.

Pathogen-mediated selection favours the maintenance of innate immunity gene polymorphism in a widespread wild ungulate.

Toll-like receptors (TLR) play a central role in recognition and host frontline defence against a wide range of pathogens. A number of recent studies have shown that TLR genes (Tlrs) often exhibit large polymorphism in natural populations. Yet, there is little knowledge on how this polymorphism is maintained and how it influences disease susceptibility in the wild.

Short-term telomere dynamics is associated with glucocorticoid levels in wild populations of roe deer.

While evidence that telomere length is associated with health and mortality in humans and birds is accumulating, a large body of research is currently seeking to identify factors that modulate telomere dynamics. We tested the hypothesis that high levels of glucocorticoids in individuals under environmental stress should accelerate telomere shortening in two wild populations of roe deer (Capreolus capreolus) living in different ecological contexts. From two consecutive annual sampling sessions, we found that individuals with faster rates of telomere shortening had higher concentrations of fecal glucocorticoid metabolites, suggesting a functional link between glucocorticoid levels and telomere attrition rate.

Under cover of the night: context-dependency of anthropogenic disturbance on stress levels of wild roe deer .

Wildlife populations are increasingly exposed to human-induced modifications of their habitats. To cope with anthropogenic stressors, animals can adjust their behaviour-for example, by shifting their activity to more sheltered habitats, or becoming more nocturnal. However, whether use of spatial and temporal adjustments in behaviour may regulate the endocrine response is poorly documented.

Pattern of latrine use by domestic cats on dairy farms and the implications for Toxoplasma gondii transmission.

Toxoplasma gondii is the parasite responsible for toxoplasmosis, a highly prevalent zoonosis that affects humans and warm-blooded animals. Faeces of infected cats can contain millions of T. gondii oocysts, which remain infectious in the environment for months.

Comparison of Three Methods to Assess the Potential for Bushpig-Domestic Pig Interactions at the Wildlife-Livestock Interface in Uganda.

Bushpigs () are considered a nuisance to farmers because of their crop raiding habits. Through their incursions into farmlands, they may interact with free-ranging domestic pigs and potentially cause transmission of infectious diseases such as African Swine Fever (ASF). The role of the bushpig in the epidemiology of ASF is poorly known and one of the gaps of knowledge is precisely the nature of interaction between bushpigs and domestic pigs.