Extended-spectrum β-lactamases (ESBL)-producing Enterobacterales have been classified as critical priority pathogens by the World Health Organization (WHO). ESBL are universally distributed and, in 2006, were firstly reported on a wild animal. Understanding the relative contributions of wild animals to ESBL circulation in the environment is urgently needed. In this work, we have conducted a nationwide study in Portugal to investigate the occurrence of bacteria carrying clinically significant antimicrobial resistance genes (ARG), using widely distributed wild ungulates as model species. A total of 151 antimicrobial resistant-Enterobacterales isolates were detected from 181 wild ungulates: 50% (44/88) of isolates from wild boar (Sus scrofa), 40.3% (25/62) from red deer (Cervus elaphus), 41.4% (12/29) from fallow deer (Dama dama) and 100% (2/2) from mouflon (Ovis aries subsp. musimon). Selected isolates showed a diversified resistance profile, with particularly high values corresponding to ampicillin (71.5%) and tetracycline (63.6%). Enterobacterales strains carried blaTEM, tetA, tetB, sul2, sul1 or dfrA1 ARG genes. They also carried blaCTX₋M-type genes, which are prevalent in human infections, namely CTX-M-14, CTX-M-15 and CTX-M-98. Strikingly, this is the first report of CTX-M-98 in wildlife. Almost 40% (n = 59) of Enterobacterales were multi-drug resistant. The diversity of plasmids carried by ESBL isolates was remarkable, including IncF, K and P. This study highlights the potential role of wild ungulates as environmental reservoirs of CTX-M ESBL-producing E. coli and in the spill-over of AMR bacteria and their determinants. Our findings suggest that wild ungulates are useful as strategic sentinel species of AMR in terrestrial environments, especially in response to potential sources of anthropogenic pollution, providing early warning of potential risks to human, animal and environmental health.

Here we study the occurrence of abnormalities on bone tissue composition and turnover mechanisms through the Pb-mediated disruption of vitamins A and D in wild ungulates living in a lead (Pb)-polluted mining area. Red deer (Cervus elaphus) and wild boar (Sus scrofa) from the mining area had significantly higher liver and bone Pb levels than controls, which were associated with the depletion of liver retinyl esters and the corresponding increase of free retinol levels both in deer and boar from the mining area. Pb-exposed adult deer had lower carbonate content in bone mineral than controls, which was associated with the increased free retinol percentage. In wild boar, the degree of bone mineralization was also positively associated with higher burdens of retinyl esters. These results suggest that Pb-associated changes in bone composition and mineralization is likely influenced by the depletion of vitamin A in wildlife exposed to environmental Pb pollution.

Antimicrobial resistance (AMR) is a recognised threat to global health. Obtaining data on the prevalence of AMR in environmental bacteria is key to understanding drivers and routes of transmission. Here, 325 Shiga toxin negative deer faecal samples—gathered from across the Scottish mainland—were screened for the presence of AMR Escherichia coli and investigated for potential risk factors associated with AMR occurrence. E. coli with resistance to antimicrobials of clinical health concern, including carbapenems and 3rd generation cephalosporins, were targeted. Ninety-nine percent of samples yielded E. coli, and the prevalence of resistant E. coli at the level of faecal samples was 21.8% (n = 71) for tetracycline, 6.5% (n = 21) for cefpodoxime, 0.3% for ciprofloxacin (n = 1), with no recorded resistance to meropenem. Potential risk factors for tetracycline and cefpodoxime resistance were investigated. The presence of broadleaved woodlands was significantly associated with both AMR phenotypes, which may relate to land use within or around such woodlands. Associated risk factors varied across resistance phenotype and deer species, with proximity or density of horses an indicator of significantly decreased and increased risk, respectively, or tetracycline and cefpodoxime resistance in E. coli from roe deer, but not from red deer. Distance from wastewater treatment plants was a significant risk factor for tetracycline resistance in E. coli from red deer but not from roe deer. Data indicated that AMR E. coli can occur in wild deer populations that are not directly exposed to the selective pressure exerted by antimicrobial treatment. Overall, resistance to critically important antimicrobials was found to be low in the studied population, suggesting no immediate cause for concern regarding human health. Utilising existing culling frameworks, wild deer in Scotland could function well as a sentinel species for the surveillance of AMR in the Scottish environment.

With concern about levels and exceedances of Canadian and provincial standards and objectives for fine particulate matter (PM2.5) in recent years, an investigation of air quality characteristics and potential local and long-range sources influencing PM2.5 concentrations was undertaken in the City of Red Deer, Alberta. The study covered the period May 2009 to December 2015. Comparatively higher concentrations of PM2.5 were observed in winter (mean: 11.6 μg/m3, median: 10 μg/m3) than in summer (mean: 9.0 μg/m3, median: 7.0 μg/m3). Exceedances of the 1 h Alberta Ambient Air Quality objective (3–31 times per year > 80 μg/m3) and the 24 h Canada-Wide Standard (2–11 times per year > 30 μg/m3) were found at the Red Deer Riverside air monitoring station, particularly in 2010, 2011 and 2015. Positive matrix factorization (PMF) followed by multiple linear regression (MLR) analysis identified a mixed industry/agriculture factor as the dominant contributor to PM2.5 (39.3%), followed by an O3−rich (biogenic) factor (26.4%), traffic (19.3%), biomass burning (10.5%) and a mixed urban factor (4.4%). In addition to local traffic, the mixed industry/agriculture factor – inferred as mostly upstream oil and gas emission sources surrounding Red Deer – was identified as another potentially important source contributing to wintertime high PM2.5 pollution days. These findings offer useful preliminary information about current PM2.5 sources and their potential contributions in Red Deer; and this information can support policy makers in the development of particulate matter control strategies if required.

Contaminant monitoring in tissues of wild species can help in the knowledge not only of their health, but also of the environmental health conditions in the zones where they live. In this study, concentrations of toxic metals (As, Cd, Hg, and Pb) and an essential metal (Zn) were measured in the hair of red deer (Cervus elaphus) and wild boar (Sus scrofa) inhabiting in protected areas of South-Western Spain. Zn (69.02 ± 1.03 mg kg⁻¹, 70.31 ± 2.22 mg kg⁻¹), Pb (0.61 ± 0.05 mg kg⁻¹, 0.68 ± 0.08 mg kg⁻¹), and As (0.33 ± 0.03 mg kg⁻¹, 0.53 ± 0.08 mg kg⁻¹) were detected in the hair of red deer and wild boar, respectively. The other metals (Cd and Hg) were under the quantification limit (0.1 mg kg⁻¹). No differences in the level of elements between both species were found. The levels of the detected elements in the hair showed low concentrations and similar to those observed in animals of the same species from unpolluted zones, reflecting a lack of contamination by these elements in the studied areas. Based on critical values of these elements established for organs of mammals, red deer and wild boar from the studied territories did not suffer toxicosis by the studied elements. Age-related differences in the content of As in the hair of red deer and age- and gender-related differences in the content of As in the hair of wild boar were detected, which should be considered for biomonitoring purposes. Finally, positive (Pb-As in both species) and negative (Zn-Pb in wild boar) interrelationships between elements were found.

The aim of this study was to evaluate the level of lead (Pb) in the livers and kidneys of free-living animals from Poland, with regard to the differences in tissue Pb content between the species. The research material consisted of liver and kidney samples collected from roe deer (Capreolus capreolus), red deer (Cervus elaphus), and wild boar (Sus scrofa) that had been hunted in 16 voivodeships of Poland. The concentration of lead had been measured using inductively coupled plasma optical emission spectrometry (ICP-OES) method. The results show that differences in lead concentration in the organs depended on the geographic location. In roe deer and red deer, the highest mean lead concentrations in the livers and kidneys, observed in the central region of Poland, were twice as high as the lowest concentration of Pb in these animals from the northeastern region of the country. In wild boar, the highest mean concentration of Pb was noted in the livers of animals from the central region of Poland and in the kidneys of animals from the northwestern region, while the lowest lead concentrations in both organs were typical for wild boar from the southeast part of the country. Our results show that areas located in the center and in the north of Poland carry most of the burden of lead bioaccumulation.

The aim of this study was to evaluate the concentrations of Pb, Cu, Zn, Rb, Cs, Sr and Ba in the muscles of red deer that were hunted in two regions of Poland (south-western and north-eastern). The data obtained were evaluated with regards to benefits and potential risk to consumers’ health. Samples for the investigations were collected in 2008 and 2009 from 50 female red deer, and the metal concentrations were determined by using the inductively coupled plasma–mass spectrometric (ICP-MS) method. The mean concentrations of Pb did not differ statistically between regions and were equal to that permitted for farm animals. The results of this study support the conclusion that the meat of the analysed animals does not pose a risk of lead intoxication. Statistically higher mean concentrations of Cu and Zn were found in the muscles of red deer from the south-western region (namely, 2.99 and 25.78 mg kg⁻¹) than those in animals from north-eastern Poland (namely, 2.61 and 23.39 mg kg⁻¹ wet weight). In terms of human nutritional needs, the meat of red deer can be considered as a good source of Cu and Zn. Furthermore, Rb, Cs, Sr and Ba concentrations did not differ statistically between regions. Their mean concentrations were 4.50, 0.09, 0.16 and 0.31 mg kg⁻¹ wet weight, respectively. Although high Cs, Sr and Ba concentrations were found, the meat of red deer does not pose a risk for adult consumers. Only high Ba content may potentially result in negative health effects for children.

The impact of mercury (Hg) pollution in the terrestrial environments and the terrestrial food chains including the impact on human food consumption is still greatly under-investigated. In particular, studies including Hg speciation and detoxification strategies in terrestrial animals are almost non-existing, but these are key information with important implications for human beings. Therefore, in this work, we report on Hg species (inorganic mercury, iHg, and monomethylmercury, MeHg) distribution among terrestrial animal tissues obtained from a real-world Hg exposure scenario (Almadén mining district, Spain). Thus, we studied Hg species (iHg and MeHg) and total selenium (Se) content in liver and kidney of red deer (Cervus elaphus; n = 41) and wild boar (Sus scrofa; n = 16). Similar mercury species distribution was found for both red deer and wild boar. Major differences were found between tissues; thus, in kidney, iHg was clearly the predominant species (more than 81 %), while in liver, the species distribution was less homogeneous with a percentage of MeHg up to 46 % in some cases. Therefore, Hg accumulation and MeHg transfer were evident in terrestrial ecosystems. The interaction between total Se and Hg species has been evaluated by tissue and by animal species. Similar relationships were found in kidney for both Hg species in red deer and wild boar. However, in liver, there were differences between animals. The possible underlying mechanisms are discussed.