Factors influencing wild boar damage to agricultural crops in Sardinia (Italy)

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.

Impacts of the Wild Boar (Sus scrofa) on the Livelihood of Rural Communities in Pakistan and Understanding Public Attitudes towards Wild Boars

Conservation goals can only be best achieved when there is firm support and cooperation from locals, especially in emerging economies where poor communities often bear most of the cost of human-wildlife conflicts (HWCs). In this study, we explored the economic losses caused by wild boars in two districts, i.e., the Peshawar district and the Nowshera district, in north-western Pakistan. Between May and June 2022, 589 respondents from 53 villages were interviewed. The results revealed that the wild boar was chiefly involved in crop raiding, causing an annual economic loss of USD 12,030 (USD 20.42/household). The highly raided crops included maize (40.24%), followed by wheat (24.95%), vegetables (22.65%), and sugarcane (6.29%). Wild boars were also held accountable for orchard damages. Most people consider the wild boar a common species in the area and want it completely eliminated. We believe that the increasing wild boar population is alarming and should be noticed. The government should collaborate with the local communities to use innovative methods to deter wild boars. Compensation schemes for crop damages should be launched. Moreover, the regular investigation of the wild boar population size and their carrying capacities should be enlisted as integral parts of wildlife management in the area.

Permeability of artificial barriers (fences) for wild boar (Sus scrofa) in Mediterranean mixed landscapes

BACKGROUND

Fences are one of the most widespread manmade features in nature, constituting an artificial limitation to the movement of wildlife. To date, their effects on wildlife behavior have been understudied but this knowledge is required to design effective management procedures. Using 21 GPS-monitored wild boar, we evaluated the permeability of different types of fences and described temporal patterns and spatial hotspots for crossing events. A fence's permeability was inferred by the crossing success, i.e., the number of times that animals crossed a barrier vs the number of times they did not cross. The vulnerability of fences at watercourses was explored by assessing whether the frequency of crossings was higher around watercourse intersections than expected by chance.

RESULTS

Well-maintained big game proof fences were the most effective in reducing successful wild boar crossings; they were, on average, 30% more efficient than livestock type fences. Crossing success was higher for males than females and during the food shortage period than in the food abundance period. The frequency of crossings around watercourses was higher than expected by chance, especially in moderately and well-maintained big game proof type fences.

CONCLUSION

While no fence type was 100% wild boar proof, well-maintained big game proof fences substantially constrained the movement of boar. However, they are vulnerable around watercourses. Managing the conflicts in which this species is involved, such as shared infections and agricultural damage, would require fences that are even more effective than the ones analyzed here, ideally in conjunction with other preventive actions. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Identification of candidate genes associated with bacterial and viral infections in wild boars hunted in Tuscany (Italy)

Wild boar (Sus scrofa L.) is one of the large mammals most spread worldwide, highly adaptable, and its population rapidly increased in many areas in Europe, including Italy, where Tuscany is considered particularly suitable for wild boar. Wild boars are potential hosts for different etiological agents, such as Brucella spp., Leptospira spp. and Pseudorabies virus and they can contribute to maintain and/or to disseminate some bacterial or viral pathogens to humans and domestic animals, above all-in free-range farms. In order to identify hypothetical genomic regions associated with these infection diseases, 96 samples of wild boars hunted in Tuscany during the 2018-2019 and 2019-2020 hunting seasons were considered. Diagnosis was achieved by serological tests and 42 Pseudorabies, 31 Leptospira and 15 Brucella positive animals were identified. All animals were genotyped with Geneseek Genomic Profiler Porcine HD (70 k) and a genome-wide scan was then performed. Significant markers were highlighted for Pseudorabies (two SNPs), Brucella (seven SNPs), and Leptospira (four SNPs) and they were located within, or nearby, 29 annotated genes on chromosome 6, 9, 12, 13, 14 and 18. Eight genes are implicated in viral (SEC14L1, JMJD6, SRSF2, TMPRSS2, MX1, MX2) or bacterial (COL8A1, SPIRE1) infections, seven genes (MFSD11, METTL23, CTTNBP2, BACE2, IMPA2, MPPE1 and GNAL) are involved in mental disorders and one gene (MGAT5B) is related to the Golgi complex. Results presented here provide interesting starting points for future research, validation studies and fine mapping of candidate genes involved in bacterial and viral infections in wild boar.

First molecular description of Macracanthorhynchus hirudinaceus in wild boars from Italy with pathomorphological and epidemiological insights

Macracanthorhynchus hirudinaceus is a zoonotic parasite affecting suids worldwide which are the definitive hosts for this helminth species. Macracanthorhynchus hirudinaceus is of significant economic and management concern due to its pathogenicity, causing intestinal obstruction and perforation in the definitive hosts. Current study is the preliminary investigation from Sardinia, Italy, reporting the pathomorphological findings and molecular characterization of M. hirudinaceus in the wild boars (Sus scrofa meridionalis). A total of 59 wild boars were examined showing acanthocephalan infection in 8 (13.6%) animals. In total, 49 parasites were collected with a mean intensity of 6.1. Comparatively higher infection levels were observed for males (16.7%) and young boars (14.3%); however, these epidemiological differences were statistically non-significant. Histopathological examination revealed the presence of a variable number of nodules (∼5 mm) in the intestine of M. hirudinaceus infested animals surrounded by a hyperemic-hemorrhagic halo. Several parasites were recovered from the intestinal lumen attached by the means of characteristic hooks showing necrosis in muscle layers. A moderate number of plump reactive fibroblasts and lesser numbers of fibrocytes were embedded with and at the borders of the inflammatory nodules in a moderate amount of homogeneous intensely eosinophilic fibrillary material rupturing the cell membrane. For molecular characterization, six isolated worms were amplified for the partial mitochondrial cox1 gene showing distinct interindividual variations. This first pathological and molecular description from southern Europe provided new knowledge about the diffusion of M. hirudinaceus in wild boars, furthering the research into the origin and transmission status of M. hirudinaceus in endemic localities.

Preserving for the future the - once widespread but now vanishing - knowledge on traditional pig grazing in forests and marshes (Sava-Bosut floodplain, Serbia)

BACKGROUND

Traditional knowledge is key for sustainability, but it is rapidly disappearing. Pig keeping in forests and marshes is an ancient, once widespread, now vanishing practice, with a major economic and ecological potential. The knowledge of pig keepers and the foraging activity of pigs are hardly documented.

METHODS

We studied the knowledge of traditional pig keepers (svinjars) on wild plants and pig foraging on the Sava-Bosut forest-marsh complex in Serbia. We conducted picture-based interviews about 234 locally common and/or salient plant species, and participatory fieldwork (11 days) and visual observation (21 days) on pig foraging.

RESULTS

181 wild plant species were known by svinjars and 106 taxa were consumed by pigs. Svinjars knew well and could name most regularly foraged species. 98 species were reported by svinjars as foraged and 56 as not eaten. 28 species were observed by the authors as eaten regularly, while 21 were nibbled and 17 avoided. Contradictory information on foraging was rare both among svinjars (8 species) and between svinjars and researchers (7 species); several of these species were rare. Leaves of 92, fruits or seeds of 21 and 'roots' of 20 species were reported or observed as eaten, usually with high seasonality. Svinjars were overall observant, but knew little about some less salient species (e.g. Veronica, Circaea). The most common forages (reported and/or observed) were fruits (Quercus, fleshy fruits), grasses (Agrostis, Glyceria), herbs (Ranunculus ficaria, Circaea), nutritious 'roots' (Carex spp., Iris), young shrub leaves (Crataegus, Carpinus) and 'tame' plants growing in the sun (Persicaria dubia, Erigeron annuus). Traditional, now extinct pig breeds were reported as less selective and more 'knowledgeable' about plants, as they received less additional fodder. Svinjars learnt their knowledge since childhood, from community members, but long-term personal observations and everyday encounters with pigs were also important sources of knowledge.

CONCLUSIONS

A deeper understanding of pig foraging could contribute to using pigs in nature conservation management, resource management and organic farming, and to a better understanding of wild boar foraging. The knowledge of svinjars is a disappearing intangible cultural heritage of European importance. Knowledge holders deserve recognition, and legal and financial support to continue this tradition.

Understanding the Dynamics of Human–Wildlife Conflicts in North-Western Pakistan: Implications for Sustainable Conservation

The high economic costs of human–wildlife conflicts (HWC) hinder long-term conservation successes, especially in developing countries. We investigated HWC by interviewing 498 respondents from 42 villages in Nowshera district, Pakistan. According to respondents, six species—the common leopard (Panthera pardus), grey wolf (Canis lupus), golden jackal (Canis aureus), red fox (Vulpes vulpes), Indian porcupine (Hystrix indica), and wild boar (Sus scrofa)—were involved in livestock predation and crop-raiding. Livestock predation (N = 670) translated into a total annual economic loss of USD 48,490 across the 42 villages, with the highest economic loss of USD 57.1/household/year attributed to the golden jackal. Crop damage by wild boar and porcupine incurred a total annual economic loss of USD 18,000. Results further showed that livestock predation was highly affected by location, prey type, prey age, and herding practices, while cereals and vegetables were preferred crops for wild boar and Indian porcupine. The grey wolf was declared as the most dangerous carnivore, followed by the golden jackal and common leopard. Negative attitude about golden jackal and wild boar prevails among 90% of the respondents of the study area. We strongly assume that the abundance of apex predators can control the economic impacts of meso-carnivores and wild boar on the community’s livelihood. Keeping relatively smaller herds may reduce carnivore attacks and educating the populous and compensation can minimise negative perceptions of HWC. To reduce HWC in the study area, there should be an incessant and timely coordination between wildlife officials and the local community.

Genital Brucella suis Biovar 2 Infection of Wild Boar (Sus scrofa) Hunted in Tuscany (Italy)

Brucellosis is a zoonosis caused by different Brucella species. Wild boar (Sus scrofa) could be infected by some species and represents an important reservoir, especially for B. suis biovar 2. This study aimed to investigate the prevalence of Brucella spp. by serological and molecular assays in wild boar hunted in Tuscany (Italy) during two hunting seasons. From 287 animals, sera, lymph nodes, livers, spleens, and reproductive system organs were collected. Within sera, 16 (5.74%) were positive to both rose bengal test (RBT) and complement fixation test (CFT), with titres ranging from 1:4 to 1:16 (corresponding to 20 and 80 ICFTU/mL, respectively). Brucella spp. DNA was detected in four lymph nodes (1.40%), five epididymides (1.74%), and one fetus pool (2.22%). All positive PCR samples belonged to Brucella suis biovar 2. The results of this investigation confirmed that wild boar represents a host for B.suis biovar. 2 and plays an important role in the epidemiology of brucellosis in central Italy. Additionally, epididymis localization confirms the possible venereal transmission.

Wild Boars Carry Extended-Spectrum β-Lactamase- and AmpC-Producing Escherichia coli

Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and methicillin-resistant Staphylococcus aureus (MRSA) represent major healthcare concerns. The role of wildlife in the epidemiology of these bacteria is unclear. The purpose of this study was to determine their prevalence in wild boars in Germany and to characterize individual isolates. A total of 375 fecal samples and 439 nasal swabs were screened for the presence of ESBL-/AmpC-E. coli and MRSA, respectively. The associations of seven demographic and anthropogenic variables with the occurrence of ESBL-/AmpC-E. coli were statistically evaluated. Collected isolates were subjected to antimicrobial susceptibility testing, molecular typing methods, and gene detection by PCR and genome sequencing. ESBL-/AmpC-E. coli were detected in 22 fecal samples (5.9%) whereas no MRSA were detected. The occurrence of ESBL-/AmpC-E. coli in wild boars was significantly and positively associated with human population density. Of the 22 E. coli, 19 were confirmed as ESBL-producers and carried genes belonging to bla_CTX-M group 1 or bla_SHV-12. The remaining three isolates carried the AmpC-β-lactamase gene bla_CMY-2. Several isolates showed additional antimicrobial resistances. All four major phylogenetic groups were represented with group B1 being the most common. This study demonstrates that wild boars can serve as a reservoir for ESBL-/AmpC-producing and multidrug-resistant E. coli.

Leptospira Survey in Wild Boar (Sus scrofa) Hunted in Tuscany, Central Italy

Leptospirosis is a re-emerging, worldwide zoonosis, and wild boar (Sus scrofa) are involved in its epidemiology as the reservoir. The aim of this study was to investigate the prevalence of Leptospira with serological, bacteriological, and molecular assays in wild boar hunted in Tuscany (Italy) during two hunting seasons. In total, 287 specimens of sera, kidneys, and liver were collected to perform microscopic agglutination tests (MATs), isolation, and RealTime PCR to detect pathogenic (lipL32 gene), intermediate (16S rRNA gene), and saprophytic (23S rRNA gene) Leptospira. Within sera, 39 (13.59%) were positive to the MAT, and Australis was the most represented serogroup (4.88%), followed by Pomona (4.18%), and Tarassovi (3.14%). Moreover, four Leptospira cultures were positive, and once isolates were identified, one was identified as L. borgpetersenii serovar Tarassovi, and three as L. interrogans serovar Bratislava. Pathogenic Leptospira DNA were detected in 32 wild boar kidneys (11.15%). The characterization through the amplification of the rrs2 gene highlighted their belonging to L. interrogans (23 kidneys), L. borgpetersenii (four), and L. kirschneri (one), while nine kidneys (3.14%) were positive for intermediate Leptospira, all belonging to L. fainei. The results of this study confirmed the importance of wild boar in the epidemiology of leptospirosis among wildlife in Central Italy.

Serological Survey on Bacterial and Viral Pathogens in Wild Boars Hunted in Tuscany

Wild boar (Sus scrofa) is one of the large mammals most spread worldwide, including Italy. This animal is highly adaptable, and its population has rapidly increased in many areas in Europe. Central Italy, as well as Tuscany region, is an area particularly suitable for wild boar. In order to verify the role of this animal species in the epidemiology of some important infectious diseases for livestock and humans, a seroepidemiological survey on Brucella spp., Leptospira spp., Mycoplasma hyopneumoniae, Pseudorabies virus (PrV), and Hepatitis E virus (HEV) has been performed on 374 sera collected from wild boar during 2015/2016 and 2016/2017 hunting seasons. Overall, 2 out of 374 sera (0.53%) tested positive to Brucella spp., 33 out of 374 sera (8.82%) tested positive for Leptospira spp., while 79 out of 374 (21.12%) were positive for M. hyopneumoniae. Considering viral pathogens, serology indicated that 107 out of 374 (28.60%) samples scored positive for PrV, while 186 out of 374 (49.73%) for HEV. This investigation indicated that wild boar free ranging in the study area are potential hosts for different etiological agents. This animal could contribute to maintaining and/or disseminating some bacterial or viral pathogens to humans (especially hunters) and domestic animals, especially in free range farms.

BOARD INVITED REVIEW: Immunocontraception as a possible tool to reduce feral pig populations: recent and future perspectives

The feral pig populations of many countries continue to increase. Scientific studies on population size are scarce, while the numbers of reported observations on presence of and damage caused by feral pigs are increasing. Feral pigs can carry and spread several diseases (including zoonotic), but African Swine Fever (ASF) is of most concern. It is a highly transmissible viral disease associated with an extremely high mortality rate. Since 2009 ASF has appeared in several European countries, with cases being identified first among local feral pigs and consequently in domestic pig production units, indicating a clear linkage with the movement of the feral pig population and the spread of the disease across national boundaries. Control of feral pig populations is currently under discussion. Because massive culling raises questions of animal welfare and ethics, fertility control could represent an important and effective means to control feral pig populations. Contraceptive vaccines have been used with some degree of success in many wild species because they are able to provide a long-term effect without any consequent health problems. However, extensive and efficacious use of vaccines to control feral pig populations is not simple. The aim of this article was to review the progress in immunocontraception use in feral pigs, providing an account of the current status and future perspectives.

Forage Consumption and Its Effects on the Performance of Growing Swine-Discussed in Relation to European Wild Boar (Sus scrofa L.) in Semi-Extensive Systems: A Review

Simple Summary

Outdoor-reared European wild boar (Sus Scrofa L.) is regarded as a delicacy by consumers due to its favourable meat properties and an association with high welfare standards. The rearing of wild boar on pasture has the potential to minimise input costs relative to conventional production systems. However, some pasture production systems have been found to perform poorly due to low growth rates. This review collates the available scientific evidence on pasture-based production of wild boar and domestic pigs, to identify factors that influence feed intake, performance, and behaviour. Factors explored include season/weather, dietary supplementation, grazing management, forage availability, herbage quality, and sward type. For example, the additional feed availability associated with pasture grazing has been shown to be a significant factor that positively correlates with dry matter intake of wild boar. This has been demonstrated to result in better feed conversion efficiency and reduced feed costs without reductions in growth rates compared to animals without access to pasture. Furthermore, the increased availability of favoured species in pasture may also promote dry matter intake. The long-term sustainability of wild boar production is dependent on the economic, social, and environmental viability of the systems. Pasture-based production systems may be one way by which this can be achieved, but only if implemented correctly.

Abstract

Due to its distinct properties, wild boar meat is considered a highly desirable consumer product, in a market that is expanding. Outdoor production is also favoured by consumers who value animal welfare and environmental sustainability when choosing meat products. There is evidence that farms that include pasture for grazing typically have reduced feeding costs. Such production systems can also be more environmentally sustainable as the input (pasture) is inedible to humans, compared to conventional indoor systems, which use human-edible feeds (e.g., soya). However, some wild boar farms have performed poorly compared to those rearing other swine such as hybrid wild boar and domestic pigs. Diet is central to all livestock production and is likely a significant influencing factor of wild boar performance, both in terms of forage consumption and nutritional composition. Other factors may also influence performance, such as weather, behaviour and grazing management. Wild boar production systems hold their own intrinsic value in a growing marketplace. However, information gathered through the study of wild boar has external applications in informing outdoor domestic pig production systems to encourage the use of pasture as part of the habitat of domestic pigs.