Wild Boar Sus Scrofa Research Articles

Identifying wild boar (Sus scrofa) crop damage hotspots to mitigate human-wild boar conflicts in northern Iran

Conflict between wild boars and humans, and the ensuing economic losses has been a global challenge for government authorities and conservation biologists for over a decade. Understanding the interplay of ecological and anthropogenic factors driving human–wild boar conflicts is paramount for formulating effective strategies to address this challenge. This study employed species distribution modeling (SDM) to predict the extent and distribution of wild boar damage risk in Taleghan, Iran, where crop cultivation and livestock rearing represent the primary livelihood activities for the local communities. Our analyses revealed that 7.7 % of the overall study area is at high risk of wild boar crop damage. The area of high risk is proportionally smaller in the no-hunting zone (1.6 %) compared to the non-protected zone (14.8 %). Also, the areas at high risk were significantly lower within the no-hunting (1200 ha) area than in non-protected area (9500 ha). The most important determinants of the occurrence of high wild boar damage are presence of orchards (30.7 %), rangeland density (24.4 %), distance to human settlements (19.4 %), and slope (10.7 %). This study successfully mapped wild boar damage risk in northern Iran. The results suggest that areas with gentle slopes, heterogeneous landscapes featuring dense vegetation (i.e., orchards and rangelands) and human settlements with sparse road networks are at the highest risk of wild boar damage. The resulting map of conflict hotspots offers a concise visualization of conflict patterns across the landscape, facilitating prioritization and development of conflict mitigation measures for areas that require immediate attention.

Beyond ungulate density: Prey switching and selection by the wolf in a recolonised area

The analysis of mechanisms underlying prey use and selection is crucial for understanding the potential for apex predators to shape ecological processes across trophic levels. Significant implications for the conservation and management of ecosystems can ensue, especially in human-modified landscapes characterised by the recent recovery of apex predators, such as those of Europe. Generalist predators may show frequency-dependent prey selection, leading to prey switching; however, there is no ubiquitous support for positive relationships between prey abundance and prey selection. In a protected area recently recolonised by the wolf Canis lupus and hosting abundant wild prey (>20 individuals/km2), we assessed prey use and selection (>3000 wolf scats analysed) throughout 7 years since wolf settlement (April 2016-to-March 2023), during which prey density was relatively stable. Wolf diet was dominated by wild boar Sus scrofa and fallow deer Dama dama (>70 % of occurrences and volume); the roe deer Capreolus capreolus and coypu Myocastor coypus represented main secondary prey. The wolf showed a clear prey switching throughout the study. In the first two years, the fallow deer was the main prey and was positively selected. Then, wild boar replaced fallow deer as main prey, and was positively selected, with a progressive decrease in the use of fallow deer throughout the years. Selection indices of wild boar were negatively associated with those of fallow deer. The relationship between selection indices and population density was inconsistent across species, being negative for the wild boar and weakly positive for the fallow deer, although the latter showed no sharp decline in the area. Concurrent studies showed increased diurnal activity of fallow deer and a consequent reduced temporal overlap with the wolf throughout years since the settlement of this predator, suggesting temporal avoidance. By supporting a minor role of prey density in mediating prey switching, our results suggest a major role of other factors (e.g., antipredator behavioural responses). Alternative substantial prey are important to buffer apex predators not only towards changes in the abundance of main prey, but also towards the effects of other factors potentially reducing prey detectability, e.g., antipredator behaviour.

From virtually extinct to superabundant in 35 years: establishment, population growth and shifts in management focus of the Swedish wild boar (Sus scrofa) population

BackgroundThe wild boar (Sus scrofa) was extinct in Sweden when a few animals established in the 1970s. Over the past 35 years, the species has made a substantial comeback. In this paper, we analyse wild boar population growth using three indices of population size. We also map the legislative decisions and research prompted by the expanding population. We discuss to what extent, in the eyes of the state, the view of wild boar and the management focus has shifted over time, from a perceived pest (eradication) to scarce (conservation), overabundant (reduction/control) or somewhere in between (sustainable management).ResultsWild boar harvest started in the early 1990s with a few hundred animals annually and peaked at 161,000 in 2020/2021. The distribution now comprises most of southern Sweden. Analyses of harvest and traffic accidents involving wild boar showed that the population grew exponentially until 2010/2011, after which the increase levelled off. Thus, logistic growth models showed the best fit for the full study period. We recorded 38 legislative decisions or commissions to government agencies regarding wild boar. The first decision in 1981 was to eradicate the free-ranging population. In 1987 however, the parliament decided that wild boar is native to Sweden and should be allowed in restricted extent. Later decisions mainly concerned hunting regulations and hunting methods as direct means to increase harvest and regulate the population. Another topic, increasing in importance over time, was to facilitate the use of wild boar meat to indirectly stimulate harvest. A local outbreak of African swine fever in 2023 necessitated a stamping out strategy in the affected area. We found 44 scientific papers regarding the present free-ranging population. Topics include movements and feeding patterns, hunting, reproduction, and population development.ConclusionsThe state historically regarded wild boar as a pest to be eradicated. This changed with the decision that wild boar should be allowed in restricted extent, suggesting a conservation approach. In response to population growth, the focus shifted to means facilitating sustainable management and, lately, reducing growth. The story of wild boar in Sweden illustrates attempts to mitigate conflicts and balance interests in wildlife management.

Modelling wild boar abundance at high resolution

Abstract By using the latest available data, we provide estimates of wild boar (Sus scrofa) distribution and abundance pre‐African Swine Fever (ASF) based on occurrence data in Europe. Secondly, as a basis for the calibration model output into densities, we used the predictions of relative abundance, and hunting yield‐based model (hunted individuals per km2), at 2x2 km for wild boar (by ENETWILD Consortium) and local wild boar densities (individuals per km2) considered reliable and obtained in the framework of the European Observatory of Wildlife (EOW), as well as some from recent literature (2015 onwards). Hunting yield predictions were considered at different spatial scales namely 5, 10 and 15 km radii buffer around localities with density estimations. The calibration of hunting yield‐based model into densities are a better fit for 15 km radius buffer and a significant relationship between model predictions of hunting yield and reliable density values at European level. This calibration of wild boar hunting yield‐based model into densities will offer the possibility to predict density values of wild boar. This will be useful to incorporate into risk factor analyses for African Swine Fever at the selected spatial range. This is the first time that absolute density estimates have been made using these two approaches for Europe, which demonstrates the added value of the observatory approach (a number of study areas where reliable density values are obtained, such as from the EOW) to generate novel information of high value for epidemiological assessment. During an ASF outbreak hunting effort will change dramatically and will take a few years to return to similar pre‐ASF levels, so post‐ASF estimates of density would be limited to areas where ASF has been present for a while. However, there will be relatively limited effect on sighting data as these rely on a number of different actors, many of whom may be expected to return to normal activities relatively soon after ASF arrives. Thus, relative post‐ASF wild boar density may be more reliable in the short term. These relative post‐ASF densities were calculated but with the limited sighting data available at the chosen locations the uncertainty was high. We advocate for the developing this nework of wildlife monitoring across Europe, and in general, harmioized wildlife monitoring programs, ensuring standardisation and consistency in the data generated and collected, which is essential for assessing management and risks related not only to ASF but other wildlife diseases.

Motivation and Habits of a Wild Boar-Hunting Community.

The wild boar (Sus scrofa) is a widespread ungulate, the populations of which have recently increased throughout most of its range. This increase has caused negative impacts on ecosystems, biodiversity, and society. Nowadays, the wild boar is considered both a valuable game and a pest. Wildlife managers need to know the habits and motivations of wild boar hunters, a key stakeholder group, for effectively managing this controversial mammal. We carried out face-to-face interviews with 134 wild boar hunters in the Evros Prefecture, in the Region of Eastern Macedonia and Thrace, northern Greece to determine their hunting habits and their motivation for hunting. Most hunters owned a hunting dog (84.3%), hunted in groups of eight to nine people for 48 days, traveled 60 km, stayed outdoors for 4 nights, and spent weekly EUR 61 on average in each hunting season. Two motivations for wild boar hunting were prominent among the hunters (assessed on a 5-point scale; 1 = strongly disagree to 5 = strongly agree): a strong recreation motivation (hunting as a recreational activity; mean score 4.159 ± 1.144 SD) and a considerable utility motivation (hunting for its use values; 3.404 ± 1.11). Both recreation and utility motivations were positively associated with the preference for further increases in wild boar populations. Sociodemographic characteristics and hunting habits variously affected motivations and preferred future population trends. The findings revealed specific habits and strong motivations among hunters. Such findings will be useful for designing and implementing education and outreach programs for informing hunters about the negative impacts of wild boars and the need for their control. The participation of hunters in the management process will be critical for its success.

<b> </b>SEASONAL<b> </b>VARIATION AND PREVALENCE OF GASTROINTESTINAL PARASITES IN CAPTIVE MAMMALS AT LAHORE ZOO

This study was conducted at Lahore Zoo, Punjab, Pakistan from January to December 2023 to assess the prevalence of gastrointestinal parasites in 10 different captive wild mammalian species. The mammals including girrafe (Giraffa), vervet monkey (Chlorocebus pygerythrus), zebra (Equus quagga), lion (Panthera leo), leopard (Panthera pardus), Rhinoceros (Rhinocerotidae), wild boar (Sus scrofa), Chinkara deer (Gazella bennettii), urial (Ovis vignei) and nilgai (Boselaphus tragocamelus) were selected. A total of 100 fresh fecal samples were collected from the animal enclosures in polythene bags (6×4 inches) 2 times during study period. Coprological examination was done using qualitative analysis such as direct smear method, sedimentation method and flotation methods. The parasitic prevalence was as follows zebra 44.5%, followed by giraffes, rhinoceroses, and wild boars at 27.8%, nilgai, urial, lion and vervet monkey at 22.3%, chinkara 16.7% and leopard 11.2%. The prevalence of gastrointestinal parasites was as Eimeria spp. (3.9%), Strongyloides spp. (3.4%), Trichuris spp. (2.8%), Giardia spp., Ascaris spp., and Strongyle spp. (2.3%), Entamoeba histolytica (1.12%), Trematode eggs (1.12%), Nematodirus (1.12%), Balantidium coli (0.6%), Haemonchus contortus (0.6%), Paramphistomum cervi (0.6%), Parascaris equorum (1.12%) and Cryptosporidium (1.12%). The overall parasitic prevalence was 23.9%, with a noticeable seasonal variation, being higher in summer (31.2%) compared to winter (17.79%). These findings highlight the significant parasitic burden in captive wild mammals. It can be concluded that regular de-worming sessions, cleaning, disinfection of enclosures and proper disposal of fecal matter should be done to reduce the overall parasitic burden.

Chemical composition of wild and domestic animals’ organism in areas of geophagy distribution in Altai Republic

Relevance. The need to study the elemental composition of the organism of wild and domestic animals in natural environments with different levels of chemical elements. Aim. To reveal features of the elemental composition of the organism of the Altai red deer (Cervus elaphus sibiricus Severtzov, 1873), wild boar (Sus scrofa scrofa Linnaeus, 1758) and domestic pigs (Sus scrofa domesticus Erxleben, 1777) in Ongudai district, Altai Republic, including the area with signs of active geophagy. Objects. Organs and tissues of wild and domestic animals. Methods. Mass spectrometry with inductively coupled plasma; atomic-emission spectrometry; ion chromatography, analytical electron microscope with energy dispersion spectrometer. Results. The median values of chemical elements concentrations in the organisms of the Altai red deer, the wild boar and the domestic pig have been determined. S, Cl and K showed the highest values in the composition of macroelements and La, Ce, Nd and Th among rare-earth and radioactive elements. Among the elemental composition features of the studied animals, an increased accumulation of Hg and Pb in the Altai red deer; metals of the Fe-group, W, as well as rare-earth and radioactive elements – in the boar; platinoids – in the domestic pig. In comparison with the results of previous studies, increased concentrations of Hg in red deer kidneys, W in boar bronchi and Pb in the brain of domestic pigs were recorded. Assumptions were made about the factors influencing the formation of the elemental composition of the body of animals. For red deer and wild boar these are the factors of nutrition (including geophagy) and features of accumulation of elements in bone tissue; for domestic pigs – features of forage and local metallogeny, including composition of natural waters.

Using feces to indicate plastic pollution in terrestrial vertebrate species in western Thailand.

Plastic pollution is a widespread and growing concern due to its transformation into microplastics (MPs), which can harm organisms and ecosystems. This study, aimed to identify plastic pollution in the feces of terrestrial vertebrates using convenience sampling both inside and outside protected areas in Western Thailand. We hypothesized that MPs are likely to be detectable in the feces of all vertebrate species, primarily in the form of small black fragments. We predicted varying quantities of MPs in the feces of the same species across different protected areas. Furthermore, we expected that factors indicating human presence, landscape characteristics, scat weight, and the MP abundance in water, soils, and sediments would influence the presence of plastics in feces. Among 12 terrestrial species studied, potential MPs were found in 41.11% of 90 samples, totaling 83 pieces across eight species including the Asian elephant (Elephas maximus), Eld's deer (Rucervus eldii), Dhole (Cuon alpinus), Gaur (Bos gaurus), Sambar deer (Rusa unicolor), Wild boar (Sus scrofa), Northern red muntjac (Muntiacus vaginalis), and Butterfly lizard (Leiolepis belliana). Specifically, 3.61% of all potential MPs (three pieces) were macroplastics, and the remaining 96.39% were considered potential MPs with the abundance of 0.92 ± 1.89 items.scat-1 or 8.69 ± 32.56 items.100 g-1 dw. There was an association between the numbers of feces with and without potential plastics and species (χ2 = 20.88, p = 0.012). Most potential plastics were fibers (95.18%), predominantly black (56.63%) or blue (26.51%), with 74.70% smaller than two millimeters. Although there were no significant associations between species and plastic morphologies, colors, and sizes, the abundance classified by these characteristics varied significantly. FTIR identified 52.38% as natural fibers, 38.10% as synthetic fibers (rayon, polyurethane (PUR), polyethylene terephthalate (PET), polypropylene (PP), and PUR blended with cotton), and 9.52% as fragments of PET and Polyvinyl Chloride (PVC). Human-related factors were linked to the occurrence of potential plastics found in the feces of land-dwelling wildlife. This study enhances the understanding of plastic pollution in tropical protected areas, revealing the widespread of MPs even in small numbers from the areas distant from human settlements. Monitoring plastics in feces offers a non-invasive method for assessing plastic pollution in threatened species, as it allows for easy collection and taxonomic identification without harming live animals. However, stringent measures to assure the quality are necessitated to prevent exogenous MP contamination. These findings underscore the importance of raising awareness about plastic pollution in terrestrial ecosystems, especially regarding plastic products from clothing and plastic materials used in agriculture and irrigation systems.

Scavenger-induced scattering of wild boar carcasses over large distances and its implications for disease management

Vertebrate scavengers provide essential ecosystem services such as accelerating carrion decomposition by consuming carcasses, exposing tissues to microbial and invertebrate decomposers, and recycling nutrients back into the ecosystem. Some scavengers do not consume carcasses on site but rather scatter their remains in the surroundings, which might have important implications for nutrient transport, forensic investigations and the spread of diseases such as African Swine Fever. However, only a few studies have investigated and measured the scatter distances. Using wild boar (Sus scrofa) carcasses and limbs, we monitored scavenging behavior and measured scatter distances of mammals. We placed 20 carcasses (up to 25 kg) and 21 separate limbs equipped with very high frequency (VHF) transmitters and monitored scavenger activity using camera traps in a mountainous region in southeast Germany. Except for one carcass, all other carcasses and limbs were scattered. We measured 72 scatter distances (of 89 scattering events; mean = 232 m, maximum = 1250 m), of which 75% were dispersed up to 407 m. Scavengers moved scattered pieces into denser vegetation compared to the half-open vegetation at provisioning sites. Red foxes (Vulpes vulpes) were the most common scavenger species, contributing to 72 scattering events (58 measured scatter distances). Our results provide evidence of scatter distances farther than previously assumed and have far-reaching implications for disease management or forensic investigations, as the broader surroundings of carcasses must be included in search efforts to remove infectious material or relevant body parts for forensic analysis.

Feeding Behavior of Wild Boars (Sus scrofa) in Bamboo Forests in Response to Shoot Emergence Phenology

Feeding Behavior of Wild Boars (Sus scrofa) in Bamboo Forests in Response to Shoot Emergence Phenology

Subclinical Ovine Gammaherpesvirus 2-Related Infections in Free-Ranging Wild Boars (Sus scrofa) from Southern Brazil.

Ovine gammaherpesvirus 2 (OvGHV2), is a Macavirus and the cause of sheep-associated malignant catarrhal fever (SA-MCF), in which sheep are the asymptomatic reservoir hosts. Susceptible mammalian populations infected by OvGHV2 may develop clinical SA-MCF or subclinical infections. All members of the Macavirus genus known to be associated with MCF are collectively referred to as the MCF virus (MCFV) complex. This report describes the occurrence of subclinical OvGHV2-related infections in free-ranging wild boars (Sus scrofa) from southern Brazil. Specific body organs (n = 14) and biological samples (nasal and oral swabs; n = 17) were collected from 24 asymptomatic wild boars from a conservation unit located within the Central-eastern mesoregion of Paraná State. Organs were processed to observe histopathological patterns suggestive of diseases of domestic animals; only pulmonary samples were used in an immunohistochemical assay designed to detect MCFV tissue antigens. Furthermore, all samples were submitted to molecular assays designed to detect the OvGHV2 tegument protein gene. Viral-induced pneumonia was diagnosed in two wild boars; one of these contained OvGHV2 DNA, with MCFV antigens identified in the other. Additionally, MCFV tissue antigens were detected within pulmonary epithelial cells of the lungs with and without pulmonary disease. Collectively, OvGHV2 was detected in 37.5% (9/24) of all wild boars, with detection occurring in the organs of 57.1% (8/14) wild boars and the oral cavity of one animal. These results demonstrated that these wild boars were subclinically infected by OvGHV2, and that infection produced typical pulmonary alterations. In addition, the detection of OvGHV2 within the oral cavity of one wild boar may suggest that this animal may be a potential disseminator of this pathogen to susceptible animal populations, including livestock and wildlife, acting as a possible bridge host for OvGHV2. Furthermore, infection by OvGHV2 probably occurred due to incidental contact with asymptomatic sheep maintained within the surrounding rural areas and not within the conservation units.

Do exotic invasive mammals disturb the native fauna? Spatiotemporal distribution and overlap between species in a national park of Argentina.

Monitoring the invasive exotic species and their effect on native fauna is fundamental for their effective control. The objective of this research is to evaluate the spatiotemporal distribution and overlap of medium-large-sized fauna in El Palmar National Park, Argentina, to consider potential negative interactions between native and exotic species. Camera traps were distributed in 27 sites between 2017 and 2019. Spatial and temporal overlap was estimated for every pair of exotic-native taxa. With 2673 camera days, two exotic and seven native taxa were recorded. All species were distributed along the extension of the National Park but in different numbers of sites. Exotic axis deer (Axis axis) was recorded in all sites but one, and exotic wild boar (Sus scrofa) occurred at only one-third of the sites surveyed. The occurrence of native mammals ranged between 26% (Geoffroy's cat, Leopardus geoffroyi) and 67% (capybara, Hydrochoerus hydrochaeris). Spatial overlap between native and exotic species was high overall and was higher in winter when species moved over larger areas to look for limited resources. Except for greater rhea (Rhea americana), which was diurnal, all species had crepuscular or nocturnal patterns. Both exotic species had an intermediate/high overlap in their activity pattern with almost all native species, including some species with similar diets, but the hours of their maximum activities did not strictly coincide. However, the existence of differences in the exotic species' activity patterns compared to their patterns in other areas where they inhabit could indicate segregation in daily activity to relax competition.

When and where? Day-night alterations in wild boar space use captured by a generalized additive mixed model.

Wild boar (Sus scrofa), an abundant species across Europe, is often subjected to management in agro-ecosystems in order to control population size, or to scare them away from agricultural fields to safeguard crop yields. Wild boar management can benefit from a better understanding on changes in its space use across the diel cycle (i.e., diel space use) in relation to variable hunting pressures or other factors. Here, we estimate wild boar diel space use in an agro-ecosystem in central Belgium during four consecutive "growing seasons" (i.e., April-September). To achieve this, we fit generalized additive mixed models (GAMMs) to camera trap data of wild boar aggregated over 1-h periods. Our results reveal that wild boar are predominantly nocturnal in all of the hunting management zones in Meerdaal, with activity peaks around sunrise and sunset. Hunting events in our study area tend to take place around sunrise and sunset, while non-lethal human activities occur during sunlight hours. Our GAMM reveals that wild boar use different areas throughout the diel cycle. During the day, wild boar utilized areas in the centre of the forest, possibly to avoid human activities during daytime. During the night, they foraged near (or in) agricultural fields. A post hoc comparison of space use maps of wild boar in Meerdaal revealed that their diurnal and nocturnal space use were uncorrelated. We did not find sufficient evidence to prove that wild boar spatiotemporally avoid hunters. Finally, our work reveals the potential of GAMMs to model variation in space across 24-h periods from camera trap data, an application that will be useful to address a range of ecological questions. However, to test the robustness of this approach we advise that it should be compared against telemetry-based methods to derive diel space use.

Range-wide camera traps reveal potential prey species for Javan leopards

Prey depletion poses a threat to large carnivores worldwide. The Javan leopard (Panthera pardus melas), the last remaining apex predator on the Indonesian island of Java, is facing numerous threats from human activities including poaching, habitat loss and prey depletion. Despite the fact that the Javan leopard is an adaptable and opportunistic predator capable of surviving in various environments, our understanding of its prey and predator-prey interactions is still limited, which is crucial for their conservation. Using camera trap data collected from four national parks (i.e., Ujung Kulon, Gunung Gede Pangrango, Meru Betiri, Alas Purwo) that represent four distinct terrestrial ecoregions across the island of Java, we investigated the species richness, relative abundance, and spatial-temporal overlap in activity patterns between the Javan leopard and other animals that coexist in the same location. Our analysis of 7461 independent photos, covering 12,983 camera trap days, revealed that areas with the presence of Javan leopards exhibited higher species richness and abundance compared to those without the presence of Javan leopards. In addition, we found that the activities of banteng (Bos javanicus), barking deer (Muntiacus muntjak), Javan deer (Rusa timorensis), Javan mousedeer (Tragulus javanicus), wild boar (Sus scrofa), junglefowl (Gallus spp.), spangled ebony langur (Trachypithecus auratus), Javan rhino (Rhinoceros sondaicus), long-tailed macaque (Macaca fascicularis) and dhole (Cuon alpinus) were highly overlapping with those of Javan leopards in space and time, suggesting that these species are potential candidate prey for Javan leopards. To our knowledge, this is the first comprehensive investigation of potential prey for the Javan leopard that utilizes camera traps from all four types of terrestrial ecoregions on Java Island. The findings of this study may serve as essential information for the conservation of this critically endangered species.

Comparative analysis of the longissimus muscle proteome of European wild boar and domestic pig in response to thermal processing

This study tries to fill the knowledge gap regarding differences in the expression of proteins in the meat of European wild boar (Sus scrofa scrofa) and domestic pig (Sus scrofa domestica), considering the impact of thermally induced degradation. We assessed relative protein changes between cooked longissimus thoracis et lumborum (LTL) muscle proteomes by using mass spectrometry, chemometric, label-free proteomic, and bioinformatic tools. Among 30 differentially abundant proteins identified MyHC-2a, ATPs-α, CK-S, ADP/ATPt1, IDH2, and MyBP-C1 were upregulated (x > 1) whereas NEB, γ-ENO and EPSF were downregulated (x < 1) in wild boar. ShinyGO and KEGG database pathway analyses revealed that these proteins are mainly involved in processes related to muscle contraction and various pathways of glucose metabolism and energy production. Protein expression changes could have been caused by the different muscle activity of wild animals in response to prolonged movement associated with foraging for food in the natural environment.

First report of Echinococcus granulosus genotype 1 in a wild boar (Sus scrofa) from China.

Echinococcosis is a worldwide disease endemic to the western region of China. In 2023, echinococcosis was detected in one of 27 wild boars (Sus scrofa) in Yili Prefecture, Xinjiang, northwestern China. Histopathological staining and full sequence mitochondrial (mt) analysis were used to determine the infection genotype. Echinococcus granulosus was detected in the wild boar liver, and the cystic lesion characteristics indicated the E. granulosus genotype (G1). This case is the first confirmation of wild boar serving as a transmitter for the G1 genotype of E. granulosus within China. These findings suggest that surveillance is needed to assess the risk of E. granulosus sensu lato transmission to humans and wild animals.

Microscopic detection and molecular characterization of Sarcocystis miescheriana in wild boars (Sus scrofa): first report from Greece.

The genus Sarcocystis includes protozoan parasites with an indirect life cycle. Sarcocystis spp. can infect various animal species and humans, causing sarcocystosis, a parasitosis of economic importance and zoonotic concern. Wild boars can act as intermediate hosts for Sarcocystis miescheriana and the zoonotic Sarcocystis suihominis that infects humans by consumption of raw or undercooked infected swine meat. In the present study, the diaphragmatic muscle tissue of 123 wild boars hunted in Greece was examined to determine the frequency of Sarcocystis spp. The samples were examined by tissue compression and molecular techniques. Under light microscopy, 34 out of 123 (27.6%) wild boars tested positive for Sarcocystis spp., while a higher infection prevalence (75%) was revealed by multiplex PCR performed in 100 of the samples. The partial mtDNA cox1 gene (~ 1100bp) of 20 samples tested positive for S. miescheriana by multiplex PCR was amplified and sequenced. Sarcocystis miescheriana was identified as the only species involved in these infections. This is the first study on the prevalence of Sarcocystis spp. in wild animals in Greece. Further, large-scale surveys are needed to assess the prevalence and species of this parasite in Greece and to design efficient control and preventive measures in a One Health perspective.

Sleep in the wild: the importance of individual effects and environmental conditions on sleep behaviour in wild boar.

Sleep serves vital physiological functions, yet how sleep in wild animals is influenced by environmental conditions is poorly understood. Here we use high-resolution biologgers to investigate sleep in wild animals over ecologically relevant time scales and quantify variability between individuals under changing conditions. We developed a robust classification for accelerometer data and measured multiple dimensions of sleep in the wild boar (Sus scrofa) over an annual cycle. In support of the hypothesis that environmental conditions determine thermoregulatory challenges, which regulate sleep, we show that sleep quantity, efficiency and quality are reduced on warmer days, sleep is less fragmented in longer and more humid days, while greater snow cover and rainfall promote sleep quality. Importantly, this longest and most detailed analysis of sleep in wild animals to date reveals large inter- and intra-individual variation. Specifically, short-sleepers sleep up to 46% less than long-sleepers but do not compensate for their short sleep through greater plasticity or quality, suggesting they may pay higher costs of sleep deprivation. Given the major role of sleep in health, our results suggest that global warming and the associated increase in extreme climatic events are likely to negatively impact sleep, and consequently health, in wildlife, particularly in nocturnal animals.

Taylor’s law and quasi-experimental hunting of invasive wild boar and axis deer in a protected area of north-eastern Argentina

Context Overabundant ungulate populations frequently cause ecological and economic damage and are difficult to control. Sustained culling efforts at El Palmar National Park have largely reduced wild boar (Sus scrofa) numbers and damage but have failed to halt the ever-increasing abundance of axis deer (Axis axis) for undefined reasons. Multi-year camera-trap surveys indicated a mismatch between deer core activity and the usual timing of hunting sessions. Aim We used the spatial and temporal forms of Taylor’s law (TL, a power relationship between the sample mean and sample variance) to test whether overnight hunting sessions are more effective for culling axis deer and wild boar than are daytime sessions, and assessed whether they modify ungulate harvest composition. Methods We implemented a quasi-experimental trial (i.e. ‘experiments in which units are not assigned to conditions randomly’), including nine alternating blocks of four to seven hunting sessions each (overnight or daytime) in which an average of 42 hunter groups performed controlled shooting over bait from fixed elevated blinds, retrieved, sexed, weighed and measured all quarry. Key results The relationship between the mean and variance of ungulate crude catch per hunting-party session and crude catch per unit effort (CPUE, where effort is measured in hunting-party hours) by hunting shift satisfied the spatial and temporal TL. On average, axis deer catch was 2.39–2.61 times greater in overnight than in daytime sessions, whereas CPUE indices were 1.54–1.73 times greater. For wild boar, overnight sessions returned catches similar to (0.94–1.03×), and a significantly lower CPUE (0.63–0.67×) than for daytime sessions. The harvest indices were substantially aggregated in daytime sessions only, and were consistently skewed towards yearlings or subadults and males, especially among adult deer. Overnight sessions culled proportionally more adults and more pregnant hinds and sows than did daytime sessions, and significantly heavier deer and wild boar males. Conclusions Overnight sessions were substantially more effective for culling deer than were daytime sessions, and selected for individuals with greater fitness. Stage- and male-skewed harvest most likely explains the steady population growth of axis deer despite increasing hunting pressure over a decade. Implications Adjusting the schedule of hunting sessions to time intervals of peak ungulate activity substantially increased the efficiency of management efforts in terms of removal rates and reproductive value of the culled specimens.

Refining animal welfare of wild boar (Sus scrofa) corral-style traps through behavioral and pathological investigations.

Wild boar trapping has been used as a management tool to control wild boar populations. However, it is increasingly criticized due to animal welfare concerns. While cortisol levels have been used to assess trap-related stress in wild boar, data on trap-related injuries and behavioral data are scarce. We aimed to evaluate three different corral-style traps for wild boar according to available mammal trapping standards to investigate and refine animal welfare in wild boar trapping. We examined 138 wild boars captured and killed by head shot in 27 capture events. Traps were closed by remote control only if the complete group were trapped. The behavior of the animals in the trap and during culling was recorded on video. All wild boars were examined and a pathological and radiological examination of the heads for trap- and shot-related injuries followed. Trap-related injuries occurred in 33% of the animals with superficial mild skin defects to skull fractures. One out of three traps met all the set requirements. A wire-meshed trapping system failed all. After installing an incomplete barrier in the center of the trap to slow down trapped animals, the fracture rate in one trap type was significantly reduced by 29% (p < 0.05). Our data showed that the type of trap (p = 0.007) and the number of animals trapped at once (p = 0.002) had a significant influence on the number of escape attempts. Trapping larger groups reduced the escape attempts. We emphasize the importance of an accurate pathological examination to evaluate animal welfare in traps and call for adjusting the injury categories listed in the standards and make a proposal for wild boar live trapping.