Search Results (147)

The subgenus Megatrypanum Hoare, 1964, with the type species Trypanosoma theileri Laveran, 1902, comprises stercorarian trypanosomes of mammals. A substantial portion of this subgenus consists of T. theileri-like trypanosomes parasitizing cervids and bovids worldwide. Similar to most other members of the genus Trypanosoma that lack obvious economic importance, the biology of T. theileri-like trypanosomes remains poorly understood. In particular, fundamental aspects such as their host specificity, host–parasite interactions, and the morphology of developmental stages have been studied only to a limited extent. In this work, we provide a detailed description of the development and cellular organization of T. theileri-like trypanosomes in the horsefly Hybomitra montana using transmission electron microscopy (TEM). We show for the first time that T. theileri-like trypanosomes possess a well-developed cytostome–cytopharyngeal complex, morphologically similar to those in other stercorarian trypanosomes. This complex is present in the studied trypanosomes at the epimastigote stage and degrades during metacyclogenesis. In the host ileum, epimastigotes and trypomastigotes at different stages of metacyclogenesis are embedded in a fibrillar matrix that isolates them from the gut lumen. This promotes their accumulation in the vector, thereby increasing the efficiency of future infection of the vertebrate host, which occurs via contamination of the oral mucosa. Full article

Sarcocystis spp. are common intracellular protozoan parasites of wild and domestic ungulates, yet data regarding their occurrence and molecular diversity in roe deer (Capreolus capreolus) from Romania remain scarce. The present study investigated the epidemiology and molecular diversity of Sarcocystis spp. in roe deer from western Romania and assessed the phylogenetic relationships of the detected isolates. A total of 132 striated muscle samples were collected from roe deer harvested in Arad, Bihor, and Timiș counties during 2023–2025 and examined microscopically for the presence of sarcocysts. Positive samples were subjected to PCR amplification and sequencing of the 18S rRNA gene. Sarcocysts were detected in 102/132 animals, yielding an overall prevalence of 77.3% (95% CI: 69.4–83.7). Infection prevalence increased significantly with host age (p < 0.001) and was significantly higher in males than in females (p < 0.05), whereas no significant differences were observed among counties or sampling years (p > 0.05). Molecular analysis of 30 representative isolates identified three Sarcocystis species: Sarcocystis gracilis (46.7%), S. linearis (33.3%), and S. entzerothi (20.0%), with S. gracilis being the predominant species. Phylogenetic analysis based on partial 18S rRNA sequences confirmed species-level identification and demonstrated close clustering of Romanian isolates with homologous European reference sequences, indicating high genetic similarity and limited phylogeographic structuring. To the authors’ knowledge, this study represents the first molecular characterization of Sarcocystis spp. in roe deer from Romania and expands current knowledge on the epidemiology, species diversity, and phylogenetic relationships of roe deer-associated Sarcocystis in Europe. Full article

Gastrointestinal microbiota are essential for fiber degradation, energy metabolism, nutrient utilization, and environmental adaptation in ruminants. Although sika deer and reindeer both belong to the family Cervidae, they differ in ecology, feeding habits, and digestive physiology, which may be reflected in their gastrointestinal microbiota. Here, we used 16S rRNA amplicon sequencing to characterize the gastrointestinal microbial communities of healthy 5-year-old male sika deer and reindeer, with particular attention to taxonomic composition, diversity patterns, and predicted functional profiles across anatomical segments. Both species were dominated by a limited number of highly abundant taxa, but clear interspecific differences were observed. At the phylum level, Bacillota and Bacteroidota predominated in both species, whereas Methanobacteriota was more abundant in reindeer and Bacillota was relatively more abundant in sika deer. At the genus level, methanogen-associated taxa were more prominent in reindeer, whereas Bacteroides, Prevotellaceae, and fiber-degradation-related taxa were more abundant in sika deer. Distinct segment-specific microbial patterns were observed along the gastrointestinal tract, especially among the foregut, small intestine, and hindgut. Alpha diversity varied across segments, whereas beta diversity showed clear separation among segments. Functional prediction indicated differences mainly in the overall structure of predicted functional profiles rather than in individual pathways. These findings provide baseline information for understanding gastrointestinal microecology and adaptive mechanisms in cervids. Full article

Background/Objectives: The emergence of antimicrobial resistance (AMR) within a One Health framework highlights the role of wildlife as environmental reservoirs. Because wild game is an increasingly important meat source, hygienic handling during evisceration is critical to prevent carcass contamination from internal tissues such as mesenteric lymph nodes (MLNs). This study aimed to investigate the occurrence and antibiotic resistance (AR) profiles of Escherichia coli isolated from the MLNs of hunted wild ungulates in western Romania to better understand microbiological hazards along the game meat supply chain. Methods: MLN samples were aseptically collected from 103 legally hunted wild boars (Sus scrofa, n = 78) and cervids (Capreolus capreolus and Cervus elaphus, n = 25) across two hunting grounds. E. coli isolation was performed utilizing selective Tryptone Bile X-Glucuronide agar. Subsequent biochemical identification and phenotypic antimicrobial susceptibility testing were conducted using the automated VITEK^® 2 system. Results: The overall E. coli isolation rate was 72.8% (75/103). Analyzed by host species, the bacterium was recovered from 79.4% of the sampled wild boars (62/78) and 52.0% of the cervids (13/25). Phenotypic resistance to at least one antibiotic agent was observed in 25.3% (19/75) of the isolates, most frequently against cephalosporins (cefalexin, 21.3%) and penicillins (ampicillin, 24.0%). Multidrug resistance (MDR) was identified in 20.0% (15/75) of the isolates. Conclusions: The detection of MDR E. coli phenotypes within the MLNs of free-ranging game indicates the penetration of clinically relevant resistance mechanisms into sylvatic environments. These findings underscore the potential risk of internal carcass contamination during field evisceration, highlighting the critical need for strict hygiene practices to ensure game meat safety. Full article

The Patagonian huemul (Hippocamelus bisulcus) and the Southern pudu (Pudu puda) are native South American cervids that differ in body size, ecology, and conservation status. However, quantitative evidence linking vertebral trabecular microarchitecture with biomechanical behavior in these species remains scarce. This study aimed to comparatively characterize vertebral trabecular bone structure and its mechanical response using an integrative, non-destructive approach. Vertebral bodies from cervical, thoracic, and lumbar regions were analyzed using high-resolution micro-computed tomography to quantify structural parameters, followed by finite element analysis to estimate deformation and von Mises stress under standardized axial compression. Both specimens exhibited consistent regional variation, with cervical vertebrae showing lower density and organization, and thoracic–lumbar vertebrae displaying denser trabecular networks. The Southern pudu specimen appeared to present a more homogeneous microarchitecture and a relatively uniform mechanical response along the vertebral column. In contrast, the Patagonian huemul specimen tended to show greater structural heterogeneity, with apparently higher deformation and stress values, particularly in the cervical region. These findings suggest that trabecular organization may contribute to the differences in vertebral mechanical behavior observed between the analyzed specimens. This study provides a preliminary comparative baseline for understanding skeletal adaptation and structural vulnerability in South American cervid species. This exploratory analysis is based on single specimens per species and should be interpreted as preliminary evidence rather than population-level inference. Full article

Forests worldwide are increasingly affected by climate-driven stressors and large-scale disturbances that impair tree physiology, disrupt water and carbon balance, and increase mortality risk. In this context, successful natural and artificial regeneration is essential for maintaining forest continuity, carbon storage, and biodiversity. However, regeneration outcomes depend not only on site conditions but also on biotic pressures, especially browsing by cervids in temperate and boreal forests. The aim of this review was to identify and synthesize evidence on how silvicultural methods can reduce browsing damage in forest regeneration and to assess how these methods influence the underlying drivers of cervid pressure through stand structure and forage availability. We examine mechanisms operating at two spatial scales: at the microscale, regeneration type, planting density, structural heterogeneity, planting stock, and how species mixture influences browsing probability and intensity; at the macroscale, how cutting systems and the spatial and temporal arrangement of harvests shape foraging landscapes by concentrating or dispersing browse resources and edge habitats. The reviewed evidence shows that dense, structurally diverse natural regeneration can dilute browsing pressure, whereas uniform artificial regeneration may increase repeated damage, and that species composition and mixture patterns can either protect or expose palatable species. We conclude that integrating microscale regeneration design with landscape-level harvest planning can strengthen stand resilience, reduce dependence on fencing, and support climate-adaptive forest development. To the best of our knowledge, no previous review has synthesized this evidence across both micro- and macroscale silvicultural contexts. Although most of the studies included in this review originate from Europe, we believe that the knowledge presented here is relevant to the majority of boreal and temperate forests worldwide. Full article

Among the 24 tick species documented in Slovakia, Ixodes ricinus is the most widespread and abundant. In some sites, 2–5 epidemiologically important tick species co-occur. Such sites represent hotspots for studying the co-circulation of tick-borne pathogens. Sympatric occurrence of five exophilic species (I. ricinus, Dermacentor reticulatus, D. marginatus, Haemaphysalis concinna, and H. inermis) was confirmed in the environs of the Žemberovce village (Levice region, south-western Slovakia). Here, the seasonal activity and abundance of questing ticks and the tick infestation of game and sheep were investigated. Questing ticks, spleens of game, and ticks removed from game and sheep were examined for the presence of tick-borne pathogens (Babesia spp., Theileria spp., Anaplasma phagocytophilum, Rickettsia spp., Borrelia burgdorferi s.l., and Borrelia miyamotoi) by molecular methods. Among the questing ticks, I. ricinus prevailed. Presence of Babesia crassa, B. microti, Rickettsia helvetica, R. raoultii, A. phagocytophilum, Borrelia afzelii, B. garinii, B. valaisiana, B. burgdorferi sensu stricto and B. miyamotoi was detected. Dermacentor marginatus, I. ricinus and H. concinna were collected from sheep. They were infected with A. phagocytophilum, A. ovis, R. slovaca, and R. raoultii. Anaplasma phagocytophilum was detected in all examined red deer and roe deer and in 55.6% of wild boar. All cervids were positive for Theileria spp. Infestation of game with all five tick species, with a predominance of I. ricinus, was confirmed. In these ticks, A. phagocytophilum, R. helvetica, R. raoultii, Babesia sp. hc-hlj212, B. crassa, B. microti, Babesia spp. and B. miyamotoi were detected. This study confirmed the presence of B. crassa in Slovakia for the first time. The investigated area, with the co-occurrence of five exophilic tick species and a wide spectrum of tick-borne pathogens, represents an epidemiologically important hotspot with the risk of infections of humans and domestic animals. Full article

The Carpathian Basin is a coherent biogeographic unit whose wildlife populations and pathogen dynamics are increasingly reshaped by administratively fragmented governance, land-use change and linear infrastructure. This review synthesizes evidence that the permeability patterns governing host movement also structure the transboundary exchange of genes and infections, creating a connectivity substrate for conservation genetics and One Health risk. Focusing on wild boar (Sus scrofa), red deer (Cervus elaphus), roe deer (Capreolus capreolus), fallow deer (Dama dama) and the expanding golden jackal (Canis aureus), we integrate population genetic inferences with wildlife epidemiology to examine how highways, border fences and asymmetric management (e.g., supplemental, feeding practices, hunting pressure and surveillance regimes) can generate biological asymmetries across boundaries. We highlight African swine fever as an emblematic disturbance in wild boar populations, discuss cervid risks including tick-borne pathogens and chronic wasting disease (CWD) preparedness and evaluate zoonotic threats associated with carnivore expansion (e.g., Echinococcus spp.). We propose a Carpathian Basin-level monitoring and data-sharing architecture, coupling harmonized passive surveillance, strategic active surveillance for priority pathogens, and standardized genetic marker panels supported by interoperable metadata. A Basin-scale One Health approach is a pragmatic prerequisite for the coordinated prevention, early detection and resilient management of cross-border epizootics and zoonotic threats. Full article

Real-time quaking-induced conversion (RT-QuIC) is highly sensitive for prion detection; however, inhibitory factors present in tissue homogenates readily interfere with the assay. We previously reported that recombinant cervid prion protein (rCerPrP) enabled the establishment of practical RT-QuIC for detecting chronic wasting disease and atypical bovine spongiform encephalopathy (BSE) prions, i.e., detecting low levels of prions in high concentration of brain tissue homogenates. Accordingly, the present study aimed to establish RT-QuIC for detecting classical BSE (C-BSE) and classical and atypical scrapie (C- and A-scrapie, respectively). A single-step lipid extraction using a 3:1 mixture of 2-butanol and methanol was effective as a pretreatment to remove inhibitors from brain homogenates. Among three rPrPs extensively evaluated, recombinant sheep PrP (rShPrP) was the most suitable substrate for practical detection of C-BSE prions. rCerPrP-173S/177N and rCerPrP-98S/173S/177N, which carry sheep-type amino acid substations at codons 173 and 177 and at codons 98, 173, and 177, showed excellent performance for detecting C-scrapie prions. Moreover, rCerPrP-98S/173S/177N, but not rCerPrP-173S/177N, was identified as an optimal substrate for detecting A-scrapie prions. These results suggested that combining inhibitor-removal pretreatment with the optimization of rPrP substrate for each animal prions further enhanced of RT-QuIC performance. Full article

Cutaneous papillomaviruses (PVs) are host-specific DNA viruses that cause papillomas in many wild cervids, including red deer, moose, roe deer, white-tailed deer, and reindeer. Species-specific PVs such as CePV1 and AaPV1 typically induce rough, verrucous skin and mucosal lesions that, while usually benign, can impair feeding, movement, vision, or mating. A high prevalence—especially in young or immunocompromised animals—may affect population health. Transmission occurs through contact, skin microtrauma, or possibly ectoparasites. PV lesions can resemble more serious diseases, complicating diagnostics. Understanding PV diversity and ecology is important for wildlife health monitoring, conservation planning, and assessing cross-species transmission risks. Full article

Epizootic haemorrhagic disease virus serotype 8 (EHDV-8) emerged in southern Europe in 2022–2023, but clinical and pathological characterization in free-ranging wildlife remains limited. This study investigated EHDV-8-associated morbidity and mortality in wild ruminants in a 2023 outbreak in Sierras de Cazorla, Segura y Las Villas Natural Park (Jaén, Andalusia, Spain). Moribund animals demonstrated a consistent acute neuro-respiratory syndrome characterized by weakness, ataxia, nystagmus and severe dyspnoea with frothy oral discharge. On the carcasses of 39 red deer, two fallow deer, and one mouflon, necropsy was performed and subsequently histopathology and a real-time polymerase chain reaction (RT-PCR) on the collected samples. Gross lesions included marked pulmonary oedema, tracheal foam and widespread congestion, while histopathology revealed lymphoid depletion, pulmonary haemorrhage, vascular injury and renal tubular necrosis. All animals tested positive for EHDV-8 with low RT-qPCR cycle threshold values, indicating high viral loads. This series provides the first confirmed clinical, pathological, and molecular evidence of EHDV-8 infection in fallow deer and mouflon in Europe. The observations demonstrate that EHDV-8 causes a peracute systemic haemorrhagic disease in susceptible wild ruminants and underline the importance of integrated wildlife surveillance and timely diagnostic sampling during peak vector activity. Full article

Hepatitis E virus (HEV) is a significant public health concern and a leading cause of acute viral hepatitis worldwide. In recent years, HEV has been increasingly recognized as a wildlife-associated zoonotic pathogen, with numerous free-ranging species contributing to its maintenance and transmission. While domestic pigs remain the primary reservoir for human infection globally, growing evidence indicates that wild animals, particularly wild boars, cervids, lagomorphs, rodents, and carnivores, play a critical role in the ecology of HEV. Wild boars are the principal wildlife reservoir, with HEV seroprevalence in Europe ranging from less than 5% to more than 50%, including some of the highest levels reported in the Balkans. In addition to the frequent detection of HEV RNA in wild boar liver and muscle, viral RNA has also been identified in several other game species, most consistently in red deer, roe deer, and, in some regions, hares and wild rabbits, highlighting food safety risks associated with the consumption of raw or undercooked game meat. In regions such as the Balkans, where hunting activities and handling of wild game are widespread, these practices may further increase occupational and dietary exposure to HEV. Rodents may further complicate the epidemiological landscape through environmental contamination of water, soil, and farm surroundings, thereby facilitating indirect transmission pathways. As wildlife populations expand and human–animal interfaces intensify, understanding HEV dynamics in free-ranging species is essential for assessing zoonotic risks and implementing a strengthened One Health approach. This narrative review synthesizes and critically examines current evidence on HEV prevalence, molecular characteristics, and transmission pathways in wildlife, with particular emphasis on Europe and focused consideration of the Balkans as an epidemiologically heterogeneous and underrepresented subregion; examines associated public health implications; and highlights the importance of integrating wildlife into food safety and One Health surveillance frameworks. Existing knowledge gaps and limitations in wildlife surveillance are also discussed. Full article

Rumen microbiota is pivotal for nutrient metabolism and physiological adaptation in ruminants. This study investigated the rumen microbial community, fermentation parameters, and serum biochemistry of three Cervid species—Sika deer (Cervus nippon), Reindeer (Rangifer tarandus), and Milu deer (Elaphurus davidianus) (n = 5/group)—fed an identical diet. Using 16S rRNA sequencing and biochemical analyses, we found that while Bacteroidota, Firmicutes, and Proteobacteria were dominant phyla across species. Sika deer and Milu deer exhibited significantly higher microbial diversity and abundance of carbohydrate-digesting genera (e.g., Butyrivibrio, Saccharofermentans), and pathways of carbohydrate digestion and absorption, starch and sucrose metabolism compared to Reindeer. Conversely, Reindeer showed increased abundances of Lachnospiraceae ND3007 and butyrate metabolism pathway, and significantly elevated rumen volatile fatty acid concentrations, particularly acetate and butyrate. Serum profiling revealed that Milu deer had significantly higher lipid levels (CHO, TG, LDL-C) but lower total protein and AST levels compared to other species. Notably, WGCNA linked these blood lipid traits to host genes enriched in PI3K-Akt, MAPK, and bile secretion pathways. These findings demonstrate distinct species-specific rumen fermentation patterns and host metabolic adaptations, suggesting a coordinated regulation between the rumen microbiome and host genetics in Cervid. Full article

The aim of this study was to compare, using culture methods, the microflora of the small and large intestines, distinguishing pathogenic bacteria, in free-living ruminants: roe deer (Capreolus capreolus) and red deer (Cervus elaphus). Intestinal samples from six individuals of each species were collected immediately after hunting under aseptic conditions. Aerobic and facultatively anaerobic bacteria, including Lactobacillus spp., Escherichia coli, Listeria spp., and Clostridium perfringens, were quantified using standard culture methods. Statistical analysis (ANOVA) revealed no significant differences (p > 0.05) between species in any of the microbial groups analyzed, although higher mean abundances were observed in red deer, particularly in the large intestine. The results indicate that interspecific variation in cultured microbiota may reflect individual and environmental factors rather than consistent taxonomic differences. Due to the high inter-individual variability and limited sample size, this study should be considered preliminary. The results demonstrate the predominance of viable aerobic and facultative anaerobic bacterial groups in culture-based analysis and provide reference data for future metagenomic studies. This study fills an important knowledge gap, as culture-dependent studies of the gut microbiota of wild cervids are still rare due to the logistical and ethical constraints associated with sampling wild animals. Full article

The hypoxic, cold, and high-ultraviolet radiation environments at high altitude pose severe challenges to mammalian immune and metabolic systems. However, little is known about how captive forest musk deer adapt to high-altitude environments and their seasonal variations. This study analyzed peripheral blood transcriptomes of 33 captive forest musk deer (Moschus berezovskii) at high altitude (~3900 m) and low altitude (~1450 m) during autumn-winter and spring-summer seasons. Results revealed comprehensive immune suppression in the high-altitude group during autumn-winter (downregulation of complement system CFB/C2/C3, interferon pathway genes including FLT3, with only natural killer (NK) cell PRKCQ upregulated), coupled with energy-conserving metabolic reprogramming (altered carbohydrate metabolism, inhibited lipid synthesis, fat mobilization, suppressed protein degradation). During spring-summer, neutrophil antimicrobial responses (SLPI/NCF1/ELANE) and humoral immunity (B cell differentiation genes PAX5/RUNX1; class-switch enzyme AICDA) partially recovered while cellular immunity (IL15/B2M) remained suppressed, accompanied by enhanced anabolic metabolism and adipocyte differentiation. Notably, NK cell-mediated cytotoxicity showed selective enhancement despite comprehensive immune suppression, representing an energy-efficient innate defense strategy. This study provides the first characterization of seasonal immune dynamics in a high-altitude cervid species. These findings reveal persistent immune constraints in high-altitude populations and provide theoretical foundations for disease prevention and health management in captive forest musk deer at high altitudes. Full article