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White-tailed deer (Odocoileus virginianus) are a ubiquitous species in North America. Their high reproductive potential leads to rapid population growth, and they exhibit a wide range of biological adaptations that influence their interactions with vectors and pathogens. This review aims to characterize the intricate interplay between white-tailed deer and the transmission cycles of various tick- and mosquito-borne pathogens across their range in the eastern United States and southeastern Canada. The first part offers insights into the biological characteristics of white-tailed deer, their population dynamics, and the consequential impacts on both the environment and public health. This contextual backdrop sets the stage for the two subsequent sections, which delve into specific examples of pathogen transmission involving white-tailed deer categorized by tick and mosquito vectors into tick-borne and mosquito-borne diseases. This classification is essential, as ticks and mosquitoes serve as pivotal elements in the eco-epidemiology of vector-borne diseases, intricately linking hosts, the environment, and pathogens. Through elucidating these associations, this paper highlights the crucial role of white-tailed deer in the transmission dynamics of tick- and mosquito-borne diseases. Understanding the interactions between white-tailed deer, vectors, and pathogens is essential for effective disease management and public health interventions. [ABSTRACT FROM AUTHOR]

Based on principles of natural selection, high-quality individuals may benefit by selecting mates of similar phenotypic quality when given the opportunity; that is, individuals may benefit by engaging in a form of non-random mating referred to as positive assortative mating. In ungulates, the idea of mate selectivity is still highly debated, with few studies providing evidence of positive assortative mating. In white-tailed deer (Odocoileus virginianus), recent studies have suggested minimal mate selectivity based on phenotypic characteristics. However, findings from these previous studies may be due to the fact that study populations had young age structures and female skewed sex-ratios that may have limited opportunities for preferential mating. From 2008 to 2019 we studied a captive population of white-tailed deer to examine characteristics of 184 parental pairs that successfully recruited fawns, while the population underwent changes in age structure and sex ratio, and we found evidence of non-random mating in parental pairs. Specifically, for each 1-year increase in male age there was a 0.32-year increase in female age among parental pairs, and for every 1.00 cm increase in male skeletal body size there was a 0.18 cm increase in female skeletal body size. We also observed that as the male and female age structures increased over time, the slope of the relationship between male and female lifetime body percentiles of parental pairs had a greater positive increase over time. Furthermore, we observed that breeding success by younger males decreased as the age structure matured. Although, even with evidence for non-random mating, we were unable to firmly conclude these findings as assortative mating due to the fact we still observed cases where there was a large difference in age between mates, indicating some plasticity with mating. Overall, our results suggest that individuals of an older age and greater body size may select for individuals of a similar condition if provided with the opportunity. However, choosiness appears dynamic, with a decrease in selectivity when preferential mates are limited due to a young age structure or when mating opportunities decrease for poor competitors in a population with a mature age structure. [ABSTRACT FROM AUTHOR]

Simple Summary: White-tailed deer (Odocoileus virginianus) commonly develop brain abscesses. While most cases occur on the skin, antler, skull, or brain, a subset more specifically affects the pituitary gland. This study describes five cases of pituitary abscesses in free-ranging white-tailed deer, including two with novel ocular manifestations. A review of these cases emphasizes the clinical presentation, gross and microscopic lesions, demographic data, and bacteriology results. Pituitary abscesses may have a unique pathogenesis compared to other intracranial abscesses in deer and should be considered as a source of conjunctivitis and keratitis by diagnosticians, field personnel, hunters, or other outdoor enthusiasts. Intracranial abscesses are a common cause of morbidity and mortality in neurologic free-ranging white-tailed deer (Odocoileus virginianus). These infections are typically attributed to Trueperella pyogenes and occur most often in adult males with concurrent antler and skull infections. A subset of intracranial abscesses in white-tailed deer are localized to the pituitary gland, with previously described reports in five white-tailed deer. In this case series, five additional free-ranging white-tailed deer in Pennsylvania were diagnosed with pituitary abscesses at necropsy. Two cases were female deer, and four cases were yearling or juvenile deer. Two cases presented with conjunctivitis and keratitis due to extension of pituitary abscesses into the retrobulbar and peri-orbital spaces. One case had a concurrent liver abscess. This case series demonstrates a unique clinical presentation of keratitis and conjunctivitis and emphasizes the potentially unique pathogenesis for pituitary abscesses compared to other intracranial abscesses described in white-tailed deer. [ABSTRACT FROM AUTHOR]

Plants may produce induced defenses such as longer thorns or secondary compounds to cope with higher levels of herbivory. However, it is unclear if physical and chemical plant defenses increase incrementally along a gradient of herbivore densities. We hypothesized that physical and chemical anti-herbivore defenses in selected shrubs increase with increasing herbivore density. We tested our hypothesis using four 0.81 km2 paddocks on each of two ranches in southern Texas, USA, that were fenced to exclude ingress and egress by white-tailed deer (Odocoileus virginianus). Target densities of deer on each ranch were 0 (control), 25, 49, and 74 deer/km2. Pelleted feed was provided ad libitum in each paddock. In July 2014, we selected ten plants of blackbrush acacia (Vachellia rigidula), twisted acacia (Vachellia schaffneri), and spiny hackberry (Celtis ehrenbergiana) in each of the four research paddocks on each ranch. We marked stems on each plant and recorded length of the main stem, lateral stems, and thorns during July 2014–2016. We collected leaf and stem samples from 20 plants of each of the three browse species during July and October 2014 and 2015 for analysis of crude protein and tannins. Branch density of blackbrush acacia was 38 % (25 deer/km2) to 123 % (49 deer/km2) greater in deer density treatments and thorn density of blackbrush acacia was 27 % greater in treatments with 74 deer/km2 than in control treatments. Spiny hackberry branch density was 2.5 times greater in treatments with 49 deer/km2 than in control treatments. Induction of plant antiherbivore defenses with increasing deer density occurred primarily in blackbrush acacia. A key finding is that induced physical and chemical defenses in shrubs can respond to increasing herbivore density in a non-linear fashion and the combination of defense strategies can vary depending on herbivore density. [ABSTRACT FROM AUTHOR]

Context: Thermal conditions can influence animal behavior and predator–prey dynamics. Understanding the effects of temperature on animals and their interactions is of increasing importance given predictions for global warming. Objectives: We determined how temperature influenced avoidance of risky areas and habitat selection in a climate generalist, white-tailed deer (Odocoileus virginianus; hereafter “deer”), and how the effect varied between night and day in a system characterized by extreme heat and high predation risk from Florida panther (Puma concolor coryi). Methods: We collected GPS locations of 224 (79 M, 145F) deer from June through September 2015–2018 in southwestern Florida, USA. We fit step-selection functions with interactions between ambient temperature and covariates including landcover and a spatial model of predation risk informed by panther kill sites. Results: Avoidance of high-risk areas decreased with rising temperatures during night and day, indicating deer were less predation risk averse when balancing higher thermoregulatory costs. As temperatures increased during the day, deer increased avoidance of marshes and hardwood hammocks. However, temperature had weaker effects on habitat selection at night with only a moderate increase in selection of marshes with increasing temperatures. Conclusions: In systems characterized by extreme heat, thermal conditions can have strong effects on animal behavior and species interactions. While climate generalists like deer have high tolerances to thermal stress, temperature still influenced predation risk tolerance and habitat selection of deer during both day and night periods. These responses are likely even stronger in species with narrower thermal tolerances (i.e., climate specialists). Thermal conditions are an important and potentially underappreciated driver of species interactions that is likely to become more significant with climate change. [ABSTRACT FROM AUTHOR]

SARS-CoV-2 continues to transmit and evolve in humans and animals. White-tailed deer (Odocoileus virginianus) have been previously identified as a zoonotic reservoir for SARS-CoV-2 with high rates of infection and probable spillback into humans. Here we report sampling 1,127 white-tailed deer (WTD) in Pennsylvania, and a genomic analysis of viral dynamics spanning 1,017 days between April 2021 and January 2024. To assess viral load and genotypes, RNA was isolated from retropharyngeal lymph nodes and analyzed using RT-qPCR and viral whole genome sequencing. Samples showed a 14.64% positivity rate by RT-qPCR. Analysis showed no association of SARS-CoV-2 prevalence with age, sex, or diagnosis with Chronic Wasting Disease. From the 165 SARS-CoV-2 positive WTD, we recovered 25 whole genome sequences and an additional 17 spike-targeted amplicon sequences. The viral variants identified included 17 Alpha, 11 Delta, and 14 Omicron. Alpha largely stopped circulating in humans around September 2021, but persisted in WTD as recently as March of 2023. Phylodynamic analysis of pooled genomic data from Pennsylvania documents at least 12 SARS-CoV-2 spillovers from humans into WTD, including a recent series of Omicron spillovers. Prevalence was higher in WTD in regions with crop coverage rather than forest, suggesting an association with proximity to humans. Analysis of seasonality showed increased prevalence in winter and spring. Multiple examples of recurrent mutations were identified associated with transmissions, suggesting WTD-specific evolutionary pressures. These data document ongoing infections in white-tailed deer, probable onward transmission in deer, and a remarkable rate of new spillovers from humans. Author summary: SARS-CoV-2 continues to evolve and circulate in humans and animals. Sometimes accumulating genetic changes give rise to new viral variants, the origins of which are incompletely understood and may involve transmissions between humans and animals. White-tailed deer (Odocoileus virginianus) is one of several host species known to harbor SARS-CoV-2 at high prevalence. We thus studied circulation and evolutionary dynamics of SARS-CoV-2 in 1,127 white-tailed deer in Pennsylvania from 2021 to 2024. Prevalence was higher in white-tailed deer in regions with crop coverage rather than forest. Analysis of seasonality showed increased prevalence in winter and spring. Our viral genome sequence analysis identified white-tailed deer as a SARS-CoV-2 reservoir of ancestral and highly divergent lineages consistent with genetic distances similar to new variants that have emerged in the human population. We found multiple examples of recurrent mutations in independent suspected spillover events, consistent with selective pressures in white-tailed deer. Together, these findings provide a unique longitudinal perspective on SARS-CoV-2 circulation, persistence, and evolution in Pennsylvania wild white-tailed deer. [ABSTRACT FROM AUTHOR]

Widespread surveillance for SARS-CoV-2 was conducted across wildlife, captive animals in zoological collections, and domestic cats in Nebraska from 2021 to 2023. The goal of this effort was to determine the prevalence, phylogenetic and spatial distribution characteristics of circulating SARS-CoV-2 variants using various diagnostic methodologies that can utilize both antemortem and postmortem samples, which may be required for wildlife such as white-tailed deer. Statewide surveillance testing revealed high variation in SARS-CoV-2 prevalence among species, with white-tailed deer identified as the primary reservoir. In 2021, seroprevalence in white-tailed deer was 63.73% (n = 91) and 39.66% (n = 237) in 2022, while virus detection in retropharyngeal lymph nodes (RLN) was 16.35% (n = 483) in 2021 and 3.61% (n = 277) in 2022. Phylogenetic analysis was conducted on 11 positive samples from 2021. This analysis revealed the presence of four lineages of the Delta variant: AY.100, AY.119, AY.3, and AY.46.4. Conversely, other species showed no virus detection, except domestic cats, which had a low seroprevalence of 2.38% (n = 628) in 2022, indicating minimal exposure. The detection of SARS-CoV-2 in white-tailed deer and the identification of multiple Delta lineages underscores the need for ongoing surveillance and the importance of using different diagnostic methodologies. These efforts are critical for understanding virus circulation and evolution in wildlife and domestic animals, informing public health strategies, and mitigating the risks of zoonotic transmission of SARS-CoV-2 and other emerging infectious diseases. [ABSTRACT FROM AUTHOR]

Protected sites managed by indigenous people have been used for decades to conserve natural resources. These sites can be considered "conservation islands" and can maintain high biodiversity. This study explores the diversity and structure of medium and large mammals in (1) four protected natural areas in Oaxaca, Mexico, and (2) two different conservation strategies: one protected natural area (PNA) and three Voluntary Conservation Areas (VCAs). Data from 30 camera traps installed by community monitoring between 2013 and 2019 were used. A total of 29,304 camera days were accumulated in the Central Valleys and the Western Mountains and Valleys province. A total of 60,725 photographic records were analyzed, resulting in 13,471 independent events. Twenty-four species of wild mammals were documented, including endangered species. VCA showed higher species richness compared to PNA. Odocoileus virginianus was the most dominant in PNA, while Dicotyles angulatus was most dominant in VCA. We found differences in species richness between the four sites and between the two conservation strategies. Both conservation strategies are effective in maintaining mammal richness. We consider that these sites can serve as conservation islands that, in turn, can inter-connect landscapes and serve as potential biological corridors. [ABSTRACT FROM AUTHOR]

Simple Summary: Deer keds are parasitic flies (Diptera) that feed on deer. They occasionally bite humans, resulting in localized skin irritation. There are many knowledge gaps persisting around the distribution of deer keds and the pathogenic microorganisms that they may transmit. In this study, 99 deer keds were collected from white-tailed deer across Massachusetts (northeastern United States). These deer keds were screened for the presence of six tick-borne pathogens using real-time PCR testing. A tick-borne bacterium, Anaplasma phagocytophilum, was found in almost 1/3 of the tested deer keds. Because of host association patterns of defined A. phagocytophilum strains, these are most likely not pathogenic to humans. No other pathogens tested were identified. These results suggest that the risk of the transmission of pathogens to humans by deer keds may be low. Based on the feeding behavior of deer keds (feeding on only one host compared to some ectoparasites that may require blood meals from multiple hosts), deer keds may be a useful tool for the monitoring and surveillance of pathogens associated with deer. Future work is needed to further assess the potential significance of deer keds to public, wildlife, and veterinary health. Deer keds (Lipoptena spp. and Neolipoptena ferrisi) are hematophagous ectoparasites that primarily infest white-tailed deer (Odocoileus virginianus) and other cervids in the United States. The distribution of deer keds in the northeastern United States and the pathogens they harbor remains relatively unexplored. In this study, we examined the geographical distribution and pathogen prevalence of deer keds in Massachusetts by collecting samples from white-tailed deer and testing for tick-borne pathogens. Deer keds were collected across the state, including in four previously unrecorded counties, indicating a wide distribution. Pathogen screening revealed the presence of Anaplasma phagocytophilum DNA in 30% of the keds, but no other pathogens were detected. The medical and biological significance of detecting A. phagocytophilum DNA in deer keds requires future studies. This research provides a baseline for the distribution and pathogen prevalence of deer keds in Massachusetts and highlights the potential of deer keds as sentinels for monitoring deer-associated microbes. [ABSTRACT FROM AUTHOR]

The rapid geographic spread of chronic wasting disease (CWD) in white-tailed deer (WTD; Odocoileus virginianus) increases the need for the development and validation of new detection tests. Real-time quaking-induced conversion (RT-QuIC) has emerged as a sensitive tool for CWD prion detection, but federal approval in the United States has been challenged by practical constraints on validation and uncertainty surrounding RT-QuIC robustness between laboratories. To evaluate the effect of inter-laboratory variation on CWD prion detection using RT-QuIC, we conducted a multi-institution comparison on a shared anonymized sample set. We hypothesized that RT-QuIC can accurately and reliably detect the prions that cause CWD in postmortem samples from medial retropharyngeal lymph node (RPLN) tissue despite variation in laboratory protocols. Laboratories from 6 U.S. states (Michigan, Minnesota, Missouri, New York, Pennsylvania, Wisconsin) were enlisted to compare the use of RT-QuIC in determining CWD prion status (positive or negative) among 50 anonymized RPLNs of known prion status. Our sample set included animals of 3 codon 96 WTD genotypes known to affect CWD progression and detection (G96G, G96S, S96S). All 6 laboratories successfully identified the true disease status consistently for all 3 tested codon 96 genotypes. Our results indicate that RT-QuIC is a suitable test for the detection of CWD prions in RPLN tissues in several genotypes of WTD. [ABSTRACT FROM AUTHOR]

In white-tailed deer (Odocoileus virginianus), closely related females form social groups, avoiding other social groups. Consequently, females infected with chronic wasting disease (CWD) are more likely to infect social group members. Culling has been used to reduce CWD transmission in high-risk areas; however, its effectiveness in removing related individuals has not been assessed. We analyzed 11 microsatellites and a mitochondrial DNA fragment to assess: (1) the genetic structure in white-tailed deer in Minnesota, USA and (2) the effectiveness of localized culling to remove related deer. For (1), we genotyped deer culled in 2019 and 2021 in three CWD management zones, and deer collected in between zones. For (2), we only included culled deer, defining "culled groups" as deer obtained in the same township-range-section and year. We compared mean relatedness among deer from the same culled group (intra-group relatedness) and among deer from different culled groups (inter-group relatedness). We did not find evidence of genetic structure, suggesting that an outbreak in any of the management zones could naturally spread to the others. Culling removed deer that were on average more related than expected by chance (intra-group relatedness > inter-group relatedness), and most highly-related deer were culled in the same bait site. [ABSTRACT FROM AUTHOR]

The parasitic protozoa, Toxoplasma gondii (T. gondii), is a model organism for one health because of its wide-ranging impacts on humans, wildlife, and domestic animals. Intermediate hosts, including white-tailed deer (Odocoileus virginianus), have been implicated in its maintenance. Prior analysis of Toxoplasma gondii seroprevalence in New York State deer focused on rural areas; however, the high density of domestic cats (Felis catus) in urban areas has been implicated in its spread amongst deer. To address this, the seroprevalence of Toxoplasma gondii was assessed across two suburban and urban areas with known deer overabundance in Onondaga and Suffolk County. Here, domestic cats are the only likely definitive host. Between 2019 and 2023, serum from culled deer was collected, and Toxoplasma gondii seropositivity was determined using the modified agglutination test. Overall seroprevalence was 49.31% (n = 144) but was significantly higher in Onondaga (64%) compared to Suffolk County (36%), despite similarities between these two regions. Deer from Onondaga also had higher antibody titers. These data suggest that although urbanization may be a predictor of Toxoplasma gondii seropositivity in deer, there are additional contributing factors. Overall, this study emphasizes the need for continued surveillance in intermediate hosts and informs public health and wildlife management decisions aimed at limiting the impact of Toxoplasma gondii. [ABSTRACT FROM AUTHOR]

Objective: Extracting DNA is essential in wildlife genetic studies, and numerous methods are available. However, the process is costly and time-consuming for non-model organisms, including most wildlife species. Therefore, we optimized a cost-efficient protocol to extract DNA from the muscle tissue of White-tailed Deer using the DNAdvance kit (Beckman Coulter), a magnetic-bead-based approach. We devised a 3 × 3 factorial design using combinations of tissue mass (10 mg, 50 mg, or 100 mg) and reaction volume (25%, 33%, and 50% of the manufacturer's recommended volumes). DNA was extracted for N = 81 tissue sub-samples (9 replicates/treatment). Results: Our target yield was 500 ng of genomic DNA per sample, sufficient for population genetic assessments. A combination of 50 mg tissue and 25% reaction volume yielded enough DNA at the lowest cost. The factorial design revealed that varying tissue mass and reagent volume significantly affected extracted DNA yield. Our study demonstrates that sufficient DNA can be extracted at 75% lower costs than the manufacturer's standard protocol. Other researchers can directly use our modified DNAdvance protocol to perform cost-effective DNA extractions. [ABSTRACT FROM AUTHOR]

The pressure on ecosystems resulting from outdoor recreational activities is increasing globally. Protected areas offer to large mammals refugia free of hunting with greater access to food resources, but the presence of humans for recreation in these areas may induce changes in behaviour, activity pattern, and habitat use. We used camera traps to model the spatial distribution and temporal activity of the white-tailed deer (Odocoileus virginianus) in a nature reserve located close to Montreal, the second largest metropole in Canada. We showed that deer limit their overlap with the public both across space and over time. White-tailed deer exhibited their highest activity level early in the morning, prior to the reserve's opening hours, indicating temporal avoidance of the public. Deer were also detected at a higher rate when further away from the hiking trail, although in less suitable habitat, indicating spatial avoidance. Human recreational activities in nature reserves open to the public may thus have an indirect effect on ecosystems, by altering the habitat use and behaviour of wildlife. [ABSTRACT FROM AUTHOR]

Background: Population growth and management in cervid species is dependent on reproductive ecology and factors influencing juvenile survival. Aspects of the female's movement behavior likely affect juvenile survival and movement patterns of pregnant and lactating females differ from non-pregnant or non-lactating females. Explanations for these differing movement patterns include change in nutritional demands for the female, isolation during parturition, and predator avoidance. White-tailed deer (Odocoileus virginianus) are an important managed cervid and a better understanding of their reproductive ecology, including the relationships between resources, movement, and juvenile survival, can better inform management. Methods: Our objective was to determine if biological factors, such as female age, fawn age, number of fawns, as well as characteristics of prepartum range affected the female's postpartum daily movement or overlap of space used pre- and postpartum in Sussex County, Delaware, USA (2,420 km2). We collected GPS locations 2 weeks pre- and postpartum on 22 individual females from 2016 to 2017. In total, we recorded data from 263 days of postpartum movement for an average of 12 days/individual. We used a hierarchical modeling process to test biological factors and prepartum home range characteristics on two aspects of postpartum movement behavior, mean hourly displacements and daily use of prepartum home range. Results: Mean hourly displacement decreased with increased female age and increased with number of known fawns alive and the female's home range size prior to parturition. We found that as fawns aged the doe increased use of the prepartum home range. Conclusions: Our results indicate that younger females are moving more than older females during lactation potentially to access higher quality habitat. This increased movement increases nutritional demand and may play a role in fawn survival. Females are more likely to use more of their prepartum home range as fawns age, a finding congruent with previous research. This differentiation in metric response (movement rate vs. space use) emphasizes the complexities of movement ecology and the importance of considering multiple dependent variables for complex behavior. [ABSTRACT FROM AUTHOR]

The blacklegged tick, Ixodes scapularis (Say) (Acari: Ixodidae), is a vector of pathogens that cause diseases including anaplasmosis, babesiosis, and Lyme disease. It is a generalist vector feeding on a wide variety of vertebrate hosts. The transmission cycles of these pathogens are affected by the tick's host selection because host species differ in their ability to clear, maintain, or amplify these pathogens. Several generalist parasites exhibit host‐associated differentiation (HAD), a process that results in genetically distinct populations associated with different host species. Knowing whether I. scapularis exhibits HAD is important to better understand the ecology of these diseases. To test for HAD in I. scapularis, whole‐genome resequencing was performed on ticks collected directly from six hosts in the southern United States (i.e., cotton mice [Cricetidae: Peromyscus gossypinus Le Conte], opossum [Didelphidae: Didelphis virginiana Kerr], raccoon [Procyonidae: Procyon lotor L.], gray fox [Canidae: Urocyon cinereoargenteus Schreber], wild boar or feral hog [Suidae: Sus scrofa L.], and white‐tailed deer [Cervidae: Odocoileus virginianus Zimmermann]). For the hosts tested, HAD was not found. However, it could not be ruled out if HAD is occurring for ticks associated with lizards in this study. The results of this study contrast with findings from another host generalist, Dermacentor variabilis (Say), that does exhibit HAD. Our results suggest that these two tick species differ in their propensity for HAD. One explanation could be that I. scapularis can mate off‐host, maintaining panmixia, whereas D. variabilis mate only on the host. The lack of HAD in I. scapularis should be confirmed by sampling ticks from lizard and rodent hosts. These results will inform control efforts and the use of area‐wide tick control strategies. [ABSTRACT FROM AUTHOR]

Background: Prion diseases are irreversible infectious neurodegenerative diseases caused by a contagious form of prion protein (PrPSc). Since chronic wasting disease (CWD)-infected white-tailed deer are strong carriers of the prion seed through corpses via scavenger animals, preemptive control based on genetic information for a culling system is necessary. However, the risk of CWD-related genetic variants has not been fully evaluated. In the present study, we carried out a quantitative estimation of the risk of a G96S single nucleotide polymorphism (SNP) of the PRNP gene to CWD infection in white-tailed deer. Methods: We carried out a literature search for genetic data of the G96S (c.286G>A) SNP of the PRNP gene from CWD-infected white-tailed deer and matched controls. We performed a meta-analysis using incorporated eligible studies to evaluate the association of the G96S SNP of the PRNP gene with susceptibility to CWD in white-tailed deer. Results: We identified a strong association between the G96S (c.286G>A) SNP of the PRNP gene and susceptibility to CWD infection in white-tailed deer using meta-analysis. We observed the most significant association in the recessive model (odds ratio = 3.0050, 95% confidence interval: 2.0593; 4.3851, p < 0.0001), followed by the additive model (odds ratio = 2.7222, 95% confidence interval: 1.9028; 3.8945, p < 0.0001) and the heterozygote (AA vs. AG) comparison (odds ratio = 2.7405, 95% confidence interval: 1.9215; 3.9085, p < 0.0001). Conclusion: To the best of our knowledge, this was the first meta-analysis of the association between the G96S (c.286G>A) SNP of the PRNP gene and susceptibility to CWD infection. [ABSTRACT FROM AUTHOR]

Geopolitical boundaries can present challenges to wildlife conservation because of varying environmental regulations, and increasingly, the existence of border barriers. As of 2024, approximately 1,023 km of border walls (i.e., steel bollard walls 5.5-9.1 m tall with interstitial spaces ≤10 cm) and 169 km of vehicle barriers (i.e., variable steel structures designed to stop vehicles but not pedestrians) exist along the USA-Mexico border. Some small wildlife passages (21.5 x 27.8 cm) were installed in border walls but few other accommodations for wildlife connectivity exist. As such, ecological consequences of border barriers may be severe and documenting the ability of wildlife to traverse these barriers will be essential to conservation efforts. We placed 36 wildlife cameras across 163.5 km of the USA-Mexico border in Arizona, USA and Sonora, MX to evaluate crossing rates through border barriers for 20 terrestrial species. We observed 9,240 wildlife events, including 1,920 successful crossing events. All focal species crossed through vehicle barriers, whereas white-tailed deer, mule deer, American black bear, American badger, wild turkey, and mountain lion appeared unable to cross through interstitial spaces in border walls. Small wildlife passages improved crossing rates for several species, including American badger, collared peccary, coyote, and mountain lion. Yet, small wildlife passages were scarce with only 13 along >130 km of continuous border wall and failed to allow American black bear, deer, and wild turkey to cross. Additional research on the impacts of border barriers and potential mitigation strategies will be critical for effective transboundary conservation. [ABSTRACT FROM AUTHOR]

Introduction: Chronic wasting disease (CWD) among cervids in Kansas has seen a consistent rise over the years, both in terms of the number of infections and its geographical spread. In this study, we assessed the occupancy patterns of CWD among white-tailed deer and mule deer across the state. Methods: Using surveillance data collected since 2005, we applied a dynamic patch occupancy model within a Bayesian framework, incorporating various environmental covariates. Using principal components analysis, 13 fully orthogonal components representing cervid habitat, soil, and elevation were derived. Competing models with different temporal patterns were fit, and the best model selected based on Watanabe-AIC values and AUC value of 0.89. Results: The occupancy pattern produced by this model revealed a steady progression of the disease toward the east and southeast of the state. A random forest analysis of covariates at annual intervals indicated that geographic location, elevation, areas occupied by mixed forests, and several soil attributes (pH, clay content, depth to restrictive layer, available water content, and bulk density) explained most of the variability in the surveillance data (R 2 = 0.96). Discussion: The findings reported in this study are the first for the state of Kansas but are consistent with previous findings from other geographic jurisdictions in the US and Canada. This consistency underscores their value in designing surveillance and management programs. [ABSTRACT FROM AUTHOR]

Investigating the relationship between the physical environment and organismal adaptation is crucial to understanding the selective pressures that drive mammalian evolution. Of the varied approaches to exploring this relationship, macroscopic tooth wear analyses have become widely used due to their economic and simple methodologies. However, more work is needed to understand how assessments of wear patterns operate within finer levels of dietary and environmental contexts. It is specifically unclear if and how tooth wear differs inter‐ and intraspecifically between geographically widespread, large‐bodied mammalian populations. This project characterizes molar hypsodonty indices and mesowear scores of white‐tailed deer (Odocoileus virginianus) and mule deer (Odocoileus hemionus) populations across North and Central America, investigating if and how molar wear and morphology vary over the deer's large and ecologically variable geographic distribution. While mesowear scores generally do not strongly track environmental signals within and between Odocoileus species, hypsodonty indices reveal a strong correlation between crown height and aridity, which likely represents an adaptive response to abrasive diets in areas with low precipitation. [ABSTRACT FROM AUTHOR]

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been detected in multiple animal species, including white-tailed deer (WTD), raising concerns about zoonotic transmission, particularly in environments with frequent human interactions. To understand how human exposure influences SARS-CoV-2 infection in WTD, we compared infection and exposure prevalence between farmed and free-ranging deer populations in Florida. We also examined the timing and viral variants in WTD relative to those in Florida's human population. Between 2020 and 2022, we collected respiratory swabs (N = 366), lung tissue (N = 245), retropharyngeal lymph nodes (N = 491), and serum specimens (N = 381) from 410 farmed and 524 free-ranging WTD. Specimens were analyzed using RT-qPCR for infection and serological assays for exposure. SARS-CoV-2 infection was detected in less than 1% of both northern Florida farmed (0.85%) and free-ranging (0.76%) WTD. No farmed deer possessed virus-neutralizing antibodies, while one free-ranging WTD tested positive for SARS-CoV-2 antibodies (3.45%). Viral sequences in infected WTD matched peaks in human cases and circulating variants, indicating human-to-deer spillover but at a lower frequency than reported elsewhere. Our findings suggest a reduced risk of SARS-CoV-2 spillover to WTD in northern Florida compared to other regions, highlighting the need for further research on transmission dynamics across North America. [ABSTRACT FROM AUTHOR]

Disease monitoring informs the opportunities for intervention by natural resource agencies tasked with managing chronic wasting disease (CWD) in wild cervids. However, allocating funds toward testing can reduce those available for education, outreach, and disease reduction. Implementation of more efficient testing strategies can help meet both an expanding need by resource managers and a burgeoning demand from the hunting public in North America. Here, we evaluated the efficacy of pooled testing using the enzyme-linked immunosorbent assay (ELISA), the current screening test used by veterinary diagnostic laboratories in the United States, and real-time quaking-induced conversion (RT-QuIC), an amplification assay that is being evaluated by the U.S. Department of Agriculture but is not yet approved or commercially available. The samples used in this study consisted of medial retropharyngeal lymph nodes (RPLNs) routinely collected by the Iowa Department of Natural Resources during the 2019–2020 surveillance season. The test pools contained tissue from one positive deer diluted in tissue from an increasing number of undetected deer, with each individual contributing an equal tissue volume. ELISA remained positive with pooling thresholds of 1:1, 1:2, 1:4, and 1:9 at a standard volume of tissue homogenate, whereas RT-QuIC remained positive with pooling thresholds of 1:1, 1:2, 1:4, 1:9, 1:19, and 1:49 at a 0.02% tissue dilution. Our results suggest that pooled testing can reduce diagnostic costs multi-fold, and RT-QuIC can be a viable screening test compatible with current field collection standards. [ABSTRACT FROM AUTHOR]

Addressing public preferences can enhance wildlife management effectiveness and reduce backlash. We conducted novel research on public acceptance of wildlife management by accounting for the role of underexplored drivers including emotion and political identity across an urban-to-rural gradient. Using data from a 2022 survey about white-tailed deer (Odocoileus virginianus) in Durham County, North Carolina, we analyzed drivers of acceptance for three management strategies: passive management, lethal management by hunting, and lethal management by professionals. Support for deer management varied across the urban-to-rural gradient, as rural residents favored hunting but were less supportive of passive management compared to urban and suburban residents. Emotions and general attitudes toward deer were the strongest predictors of management acceptance. Support for passive management was higher among residents with more positive emotions toward deer, whereas support for lethal strategies was higher among those with more negative emotions. Additionally, political identity emerged as a complex yet influential factor in shaping support for lethal management. Conservative respondents exhibited a higher acceptance of hunting, whereas liberal respondents exhibited a higher acceptance of professional sharpshooting. Collectively, our results demonstrate the ways in which emotions, politics, and other socio-demographic factors interact to influence public support for deer management across the urban–rural gradient. When direct experience with wildlife is lacking (e.g., in urban areas), emotions may act as heuristic guides that shape preferences. Managers aiming to increase deer management acceptability could integrate insights about emotional, political, and demographic drivers of public management support in communication efforts, potentially rendering urban deer management more effective. [ABSTRACT FROM AUTHOR]

The article "Observations of Turkey Vulture Mortality along a Commuter Railway in New York, USA" published in the Journal of Raptor Research discusses the impact of railroads on wildlife, specifically focusing on Turkey Vultures. The study found that Turkey Vultures are at risk of fatal collisions with trains while scavenging for carrion along the railway. The research suggests that railroads may function as "ecological traps" for vultures, leading to mortality. Recommendations are made to reduce Turkey Vulture mortality by addressing the availability of train-killed wildlife, particularly white-tailed deer, along the railway. [Extracted from the article]

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Supplemental feeding of wild ungulates has long been and remains a common practice across Europe and North America. Yet by drawing animals together, supplemental feeding can have unintended, negative effects on individual species and broader ecological processes. These include increased risk of disease transmission, intraspecific and interspecific competition, and predation, which are of management concern for white‐tailed deer (Odocoileus virginianus) in the southeastern United States given the arrival of nonnative wild pigs (Sus scrofa) and coyotes (Canis latrans). We conducted a field experiment between March and July of 2021 to assess the effects of supplemental feeding on spatiotemporal activity patterns of deer and wild pigs at wildlife feeders, and space use of coyotes in the Piedmont region of South Carolina, USA. We observed support for our hypothesis that interspecific competition through increased visitation by larger groups of competitor species reduces use of foraging sites by other subordinate ungulates, where feeders highly visited by wild pigs were rarely visited by deer. While adult deer and wild pigs generally did not shift their temporal activity patterns at feeders, juvenile temporal activity shifted to more frequent visits of feeders during the night, supporting our hypothesis that supplemental feed could increase risk to predator exposure, as coyotes tend to be active during crepuscular hours. Our findings suggest that supplemental feed put out to encourage deer activity could actually deter deer if wild pigs occupy that area, and has potential negative demographic effects if juveniles are at increased risk of predation. Collectively, based on our data, we do not recommend supplemental feeding in the southeastern United States where white‐tailed deer, coyotes, and wild pigs co‐occur. More broadly, given how widespread the legal use of supplemental feed remains across the United States, we encourage landowners and policymakers to consider the full suite of potential direct and indirect, short‐term and long‐term negative impacts supplemental feeding can have on both target and nontarget wildlife populations. [ABSTRACT FROM AUTHOR]

Lead (Pb) is a heavy metal with no clear biological benefit that is toxic to wildlife and humans. Although Pb has been banned from several consumer products, it is not regulated in ammunition for big‐game hunting (e.g., cervids) in New York, USA. Wildlife species that scavenge remains of game harvested with Pb ammunition can be exposed to bullet fragments through ingestion and potentially develop toxicosis. To make evidence‐based decisions for reducing risk from bullet‐derived Pb, we first empirically identified avian and mammalian scavengers of white‐tailed deer (Odocoileus virginianus) remains in New York through an online survey during July‐August 2023, where community members submitted images of scavengers from game cameras. We conducted species vulnerability and utility assessments using published evidence and pre‐existing frameworks. Despite inherent limitations, we documented an extensive array of avian (n = 17) and mammalian (n = 14) scavengers. We estimated bald eagles (Haliaeetus leucocephalus) and golden eagles (Aquila chrysaetos) as most vulnerable to Pb toxicosis, followed collectively by American goshawks (Accipiter atricapillus), American crows (Corvus brachyrhynchos), and common ravens (C. corax). We also determined bald eagles to be best‐suited as bioindicators of bullet‐derived Pb, followed by American goshawks. Red‐tailed hawks (Buteo jamaicensis) and great horned owls (Bubo virginianus) equally ranked third. Integrating vulnerability and utility assessments point to bald eagles as the most vulnerable scavengers to Pb toxicosis and best‐suited bioindicators of bullet‐derived Pb. Because regulation of Pb ammunition for big‐game hunting is an ongoing socio‐political issue, wildlife managers and conservationists can address health risks through monitoring species vulnerable to toxicosis and instituting surveillance programs using the most effective bioindicators. [ABSTRACT FROM AUTHOR]

Defensive traits are hypothesized to benefit prey by reducing predation risk from a focal predator but come at a cost to the fitness of the prey. Variation in the expression of defensive traits is seen among individuals within the same population, and in the same individual in response to changes in the environment (i.e., phenotypically plastic responses). It is the relative magnitude of the cost and benefit of the defensive trait that underlies the defensive trait expression and its consequences to the community. However, whereas the cost has received much attention in ecological research, the benefit is seldom examined. Even in a defensive trait as extensively studied as vigilance, there are few studies of the purported benefit of the behavior, namely that vigilance enhances survival. We examined whether prey vigilance increased survival and quantified that benefit in a natural system, with white‐tailed deer (Odocoileus virginianus) experiencing unmanipulated levels of predation risk from Florida panther (Puma concolor coryi). Deer that spent more time vigilant (as measured by head position using camera trap data) had a higher probability of survival. Indeed, an individual deer that was vigilant 75% of the time was more than three times as likely to be killed by panthers over the course of a year than a deer that was vigilant 95% of the time. Our results therefore show that within‐population variation in the expression of a defensive trait has profound consequences for the benefit it confers. Our results provide empirical evidence supporting a long‐held but seldom‐tested hypothesis, that vigilance is a behavior that reduces the probability of predation and quantifies the benefit of this defensive trait. Our work furthers an understanding of the net effects of a trait on prey fitness and predator–prey interactions, within‐population variation in traits, and predation risk effects. [ABSTRACT FROM AUTHOR]

The reintroduction of the Mexican wolf in the wilds of northwestern Mexico has allowed us to address its trophic ecology and elucidate conflicts with livestock producers: their main mortality factor. Our objective was to determine the feeding habits of wolves in Mexico, as well as the quantity and frequency of livestock predation in relation to seasonal and individual variables, through the analysis of genetically identified scats. During 2012–2022 we collected 1171 Mexican wolf scats. We extracted and sequenced DNAm and identified individuals and their sex using microsatellite analysis. We washed the scat and separated the undigested components for taxonomic identification. We estimated the frequency of prey items, the biomass it contributed to the diet, and compared prey consumption between sexes and between the birth and dispersal seasons. We constructed generalized linear models to identify the relationship between livestock presence in the diet and dietary prey richness with respect to environmental and individual variables. We identified 68 wolves that had consumed 30 species of vertebrates. Of these, white‐tailed deer (36.12%), diversionary feeding (22.79%), and cattle (25.56%) had the highest contribution to biomass. The ingestion of items was independent of the sex of the wolves but was dependent on the season. The presence of deer and diversionary feeding decreased the likelihood of cattle being ingested but also decreased the richness of items of wild species in the wolf diet. Wolves in northwestern Mexico fed mainly on large prey available in the reintroduction area, including livestock. As wolves consume livestock, it increases the risk of retaliatory actions from ranchers. Our results serve as a basis for the implementation of strategies to reduce human–wolf conflicts and set a baseline for coexistence in northwestern Mexico. [ABSTRACT FROM AUTHOR]

The root causes of forest tree regeneration failure are difficult to resolve, although numerous studies show ungulate herbivory, soil conditions, and competition from undesirable vegetation as likely contributors. To better understand the relative importance of each issue, we conducted a 7-year manipulative experiment to assess the interactive effects of white-tailed deer (Odocoileus virginianus) herbivory, soil acidity, and competing vegetation on tree regeneration in oak–hickory forests of central Pennsylvania, USA. Outcomes depended on initial tree seedling abundance, and all three factors had significant interactions. At low initial seedling abundance, fencing resulted in the greatest increase, but all treatments had a positive effect on seedling growth and abundance. At higher initial seedling abundance, abundance failed to recover 7 years after herbicide treatment and soil pH was an important predictor. When soil pH was >4.6 from lime application, seedling growth and abundance in unfenced controls with high initial abundance was comparable to the fenced-only treatment. Competing vegetation, assumed to be a symptom of excessive, long-term deer herbivory, does not seem to be the primary factor limiting tree regeneration in our study area. Ameliorating acid deposition warrants greater consideration as a management action because it could provide long-lasting benefits compared to short-term fence installations. [ABSTRACT FROM AUTHOR]

Quality deer management (QDM) is the preeminent framework by which white-tailed deer are managed in the eastern USA. Historic differences surrounding the cultures, traditions, and regulations of deer hunting exist regionally between the Midwest and Southeast, yet no published study has investigated regional differences in attitudes and opinions of QDM among deer hunters. We surveyed 9,301 deer hunters across two Midwestern states (Missouri and Ohio) and two Southeastern states (Louisiana and South Carolina) and found that hunters across regions held similar motivations for deer hunting, as well as similar attitudes and opinions of strategies and expected outcomes of QDM. However, there existed several mismatches between the practices and ideology associated with QDM among Southeastern hunters. Southeastern hunters held greater support for greater antlered bag limits, protection of does, and supplemental feeding. We postulate that these mismatches are largely driven by regional differences in cultures, traditions, and regulations surrounding deer hunting. [ABSTRACT FROM AUTHOR]

White‐tailed deer (Odocoileus virginianus) are a cervid species found mostly in the Americas. Managing white‐tailed deer requires understanding their relationship with the environment, which was characterized by Roseberry and Woolf (Wildlife Society Bulletin 1, 1998, 252) for all counties in Illinois, USA, who incorporated habitat quantity and quality in a deer habitat suitability index. However, this index was based on satellite imagery from 1996 and did not explore the smaller spatial scales used by deer. Our study addressed these gaps by developing a deer land cover utility (LCU) score for each TRS (township, range, and section), township, and county in Illinois based on the methodology outlined in Roseberry and Woolf (Wildlife Society Bulletin 1, 1998, 252) but using data from the National Land Cover Database (2001–2021). These deer LCU scores were validated against minimum deer population data using Bayesian regression with additional covariates relevant to hunting and deer density. These models performed well with Bayesian R2 values of 0.501 (TRS), 0.5 (township), and 0.969 (county). The regression coefficients for the deer LCU scores were statistically significant (95% credibility interval not containing 0) and positive at the TRS, township, and county levels, reflecting the expected relationship between minimum deer density and deer LCU. Predictions made by these regression models on new data were accurate, with the median absolute difference between the true and predicted values being 0.398 deer/km2 for TRS', 0.085 deer/km2 for townships, and 0.066 deer/km2 for counties. This deer LCU could be used in other studies about deer in Illinois or studies in which deer are a relevant factor such as investigations about deer disease or tick distribution. This modeling approach could also be adapted to different wild species, locations, and/or time periods for which land cover data is available. [ABSTRACT FROM AUTHOR]