Wild boars as sources for infectious diseases in livestock and humans

Serosurveillance of Coxiella burnetii in feral swine populations of Hawai'i and Texas identifies overlap with human Q fever incidence

Feral swine are invasive in the United States and a reservoir for infectious diseases. The increase in feral swine population and the geographic range are a concern for the spread of zoonotic diseases to humans and livestock. Feral swine could contribute to the spread of Coxiella burnetii, the causative agent of human Q fever. In this study, we characterized the seroprevalence of C. burnetii in feral swine populations of Hawai'i and Texas, which have low and high rates of human Q fever, respectively. Seropositivity rates were as high as 0.19% and 6.03% in Hawai'i and Texas, respectively, indicating that feral swine cannot be ruled out as a potential reservoir for disease transmission and spread. In Texas, we identified the overlap between seropositivity of feral swine and human Q fever incidence. These results indicate that there is a potentially low but detectable risk of C. burnetii exposure associated with feral swine populations in Hawai'i and Texas.

Endemic maintenance of human-related hepatitis E virus strains in synurbic wild boars, Barcelona Metropolitan Area, Spain

Hepatitis E virus (HEV), shared by humans, domestic animals, and wildlife, is an emerging global public health threat. Because wild boars are a major reservoir of HEV, the new zoonotic interfaces resulting from wild boar population increase and synurbization significantly contribute to increasing the risk of zoonotic transmission of HEV. This study characterizes HEV strains of synurbic wild boars and assesses their relationship with sympatric human and domestic swine HEV strains. We analyzed the faeces of 312 synurbic wild boars collected from 2016 to 2021 in the Barcelona Metropolitan Area (BMA), where there is a high density of wild boars, and found 7 HEV-positive samples among those collected between 2019 and 2020. The molecular analysis of these isolates, along with 6 additional wild boar HEV isolates from a previous study, allowed us to establish a close phylogenetic relationship between these HEV strains and human HEV isolates from sympatric blood donors and domestic pigs from Catalonia. HEV-positive wild boar samples belonged to piglet, juvenile and yearling individuals, but not adults, indicating the endemic maintenance of HEV in the wild boar population of the BMA by naïve young individuals. All wild boar HEV isolates in this study classified within HEV genotype 3. The results show, for the first time, a close molecular similarity between the HEV strains endemically maintained by the synurbic wild boars in the BMA and citizens from the same area and period. The data could also indicate that HEV infection presents a seasonal and interannual variability in wild boars of BMA. Further investigation is required to unveil the HEV transmission routes between synurbic wild boars and sympatric citizens. These findings can serve in other synurbic wildlife-human interfaces throughout the world.

Blastocystis occurrence and subtype diversity in European wild boar (Sus scrofa) from the Iberian Peninsula

The ongoing increase in wild boar populations across Europe has fostered human-wildlife conflicts, including the transmission of emerging pathogens with zoonotic importance. Blastocystis is a ubiquitous, faecal-oral transmitted protist that can cause gastrointestinal illnesses and is observed in humans and animals worldwide. The role of wildlife in the epidemiology of Blastocystis is insufficiently understood. Thus, we investigated the occurrence and subtype diversity of Blastocystis in free-ranging wild boars from the Iberian Peninsula using conventional PCR and next-generation amplicon sequencing of a fragment of the ssu RNA gene. A total of 459 wild boar faecal samples were collected across Spain (n = 360) and Portugal (n = 99) between 2014 and 2021. Blastocystis was present in 15.3% (70/459; 95% CI 12.1-18.9) of the wild boars analysed, and its occurrence was significantly higher in Portugal (34.3%, 34/99; 95% CI 25.1-44.6) than in Spain (10.0%, 36/360; 95% CI 7.1-13.6). Seven Blastocystis subtypes (ST5, ST10b, ST13-ST15, ST24b, and ST43) were detected among the surveyed wild boar populations, with greater variability detected in Portuguese samples. ST5 was identified in all the Blastocystis-positive animals, whereas 14.3% of them harboured ST mixed colonisations. Our results demonstrate that Blastocystis ST5 is particularly adapted to infect wild boars. The additional identification of zoonotic STs reinforces the role of wild boars as spreaders of zoonotic infections with public health significance.

Multicentric Study on Enteric Protists Occurrence in Zoological Parks in Portugal

Parasitic infections of the gastrointestinal tract of domestic animals play a major role in the transmission of disease, which in turn may result in financial and productive losses. Notwithstanding, studies on the burden and distribution of diarrheagenic protists in zoological gardens are still insufficient. Given the close animal-animal and animal-human interaction in these settings, Public Health concerns under the One Health context are raised. Using molecular detection tools and phylogenetic analysis, the goal of this study was to assess the occurrence of four potentially zoonotic protists-Balantioides coli, Blastocystis sp., Cryptosporidium spp. and Giardia spp.-in animals residing in zoological parks in Portugal. Occurrence of Eimeria spp. was also assessed because of its veterinary relevance. Although Blastocystis sp. represents most of the positive samples obtained (11.6%; 95% CI: 0.08-0.17), all parasites were detected (B. coli (2.9%; 95% CI: 0.01-0.06), and Cryptosporidium spp., Eimeria spp. and Giardia spp. presented the same prevalence (0.5%; 95% CI: 0.00-0.03)). We also describe the first molecular detection of B. coli in a collared peccary (Tayassu tajacu), of Blastocystis sp. in three different python species, and G. muris in a central bearded dragon (Pogona vitticeps), suggesting the broadening of the host range for these parasites.

Assessing leptospirosis and toxoplasmosis seropositivity in wild boars (Sus scrofa): Implications for public and animal health in Southern Brazil

Leptospirosis and toxoplasmosis are re-emerging zoonosis caused by infection with pathogenic spirochaetes of Leptospira and the protozoa Toxoplasma gondii, respectively. Wild boars (Sus scrofa), an exotic invasive species in Brazil, could play a role in the diseases' epidemiological cycles, but this issue is still unexplored. This study aimed to evaluate the Leptospira spp. and T. gondii seropositivity in wild boars in Rio Grande do Sul state, south Brazil. Of evaluated animals, 16% (13/80) and 85% (52/61) had antibodies to T. gondii and Leptospira spp., respectively. Sex, weight, age, hunt location and season of hunt were evaluated by their association with seropositivity for both pathogens, but none of them had statistical significance. This study revealed that wild boars should be considered as a potential source of Leptospira spp. and T. gondii dissemination for humans and animal species in shared environments in Rio Grande do Sul state.

Recent decline in hepatitis E virus prevalence among wild boars in Japan: Probably due to countermeasures implemented in response to outbreaks of classical swine fever virus infection

Previous studies have emphasized the necessity of surveillance and control measures for hepatitis E virus (HEV) infection in wild boars, an important reservoir of HEV. To assess the current situation of HEV infection in wild boars in Japan, this study investigated the prevalence and genetic diversity of HEV among wild boars captured in 16 prefectures of Japan during 2018-2023. Serum samples from 968 wild boars were examined for anti-HEV IgG antibodies and HEV RNA. The prevalence of anti-HEV IgG varied geographically from 0 % to 35.0 %. HEV RNA was detected in 3.6 % of boars, with prevalence varying by prefecture from 0 % to 22.2 %. Genotype 3 was the most prevalent genotype (91.9 %), followed by genotype 4 (5.4 %), with one strain closely related to genotype 6. The prevalence of HEV infection among wild boars decreased from 2018/2019 to 2022/2023 with significant declines in levels of anti-HEV IgG antibodies (14.5 % vs. 6.2 %, P < 0.0001) and HEV RNA (7.6 % vs. 1.5 %, P < 0.0001). Regional analysis showed varying trends, with no HEV RNA-positive boars found in several regions in recent years. A plausible factor contributing to the decline in HEV infection is the application of countermeasures, including installing fences to prevent intrusion into pig farms, implemented in response to the emergence of classical swine fever virus (CSFV) infection in wild boars and domestic pigs, with incidents reported annually since 2018. Further investigation is warranted to explore the association between countermeasures to CSFV infection and the decrease in HEV infection among wild boars.

Hepatitis E and Potential Public Health Implications from a One-Health Perspective: Special Focus on the European Wild Boar (Sus scrofa)

The hepatitis E virus (HEV) has become increasingly important in recent years in terms of risk for public health, as the main causative agent of acute viral hepatitis. It is a foodborne disease transmitted to humans through the consumption of contaminated water or contaminated food. Human-to-human transmission is sporadic and is linked to transfusions or transplants. The main reservoirs of the hepatitis E virus are domestic pigs and wild boars, although, compared to pigs, wild boars represent a lesser source of risk since their population is smaller and the consumption of derived products is more limited. These peculiarities often make the role of the wild boar reservoir in the spread of the disease underestimated. As a public health problem that involves several animal species and humans, the management of the disease requires an interdisciplinary approach, and the concept of "One Health" must be addressed. In this direction, the present review intends to analyze viral hepatitis E, with a particular focus on wild boar. For this purpose, literature data have been collected from different scientific search engines: PubMed, MEDLINE, and Google scholar, and several keywords such as "HEV epidemiology", "Extrahepatic manifestations of Hepatitis E", and "HEV infection control measures", among others, have been used. In the first part, the manuscript provides general information on the disease, such as epidemiology, transmission methods, clinical manifestations and implications on public health. In the second part, it addresses in more detail the role of wild boar as a reservoir and the implications related to the virus epidemiology. The document will be useful to all those who intend to analyze this infectious disease from a "One-Health" perspective.

Characterizing feral swine movement across the contiguous United States using neural networks and genetic data

Globalization has led to the frequent movement of species out of their native habitat. Some of these species become highly invasive and capable of profoundly altering invaded ecosystems. Feral swine (Sus scrofa × domesticus) are recognized as being among the most destructive invasive species, with populations established on all continents except Antarctica. Within the United States (US), feral swine are responsible for extensive crop damage, the destruction of native ecosystems, and the spread of disease. Purposeful human-mediated movement of feral swine has contributed to their rapid range expansion over the past 30 years. Patterns of deliberate introduction of feral swine have not been well described as populations may be established or augmented through small, undocumented releases. By leveraging an extensive genomic database of 18,789 samples genotyped at 35,141 single nucleotide polymorphisms (SNPs), we used deep neural networks to identify translocated feral swine across the contiguous US. We classified 20% (3364/16,774) of sampled animals as having been translocated and described general patterns of translocation using measures of centrality in a network analysis. These findings unveil extensive movement of feral swine well beyond their dispersal capabilities, including individuals with predicted origins >1000 km away from their sampling locations. Our study provides insight into the patterns of human-mediated movement of feral swine across the US and from Canada to the northern areas of the US. Further, our study validates the use of neural networks for studying the spread of invasive species.

Monitoring SARS-CoV-2 infection in urban and peri-urban wildlife species from Catalonia (Spain)

BACKGROUND

Human activities including deforestation, urbanization, and wildlife exploitation increase the risk of transmission of zoonotic diseases. Urban and peri-urban wildlife species often flourish in human-altered environments, with their survival and behavior heavily influenced by human-generated food and waste. In Catalonia, Spain, and other Mediterranean regions, species of rodents, including the house mouse (Mus musculus), black rat (Rattus rattus), Norway rat (Rattus norvegicus), as well as wild boar (Sus scrofa) are common in urban and peri-urban areas. These species host numerous infectious agents, including coronaviruses (CoVs), posing potential human health risks. During the coronavirus disease 2019 (COVID-19) pandemic, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) evolved to infect previously non-susceptible species, with variants capable of infecting rodents, emphasizing their importance in surveillance studies.

METHODS

The present study assessed SARS-CoV-2 presence and/or exposure in 232 rodents, 313 wild boar, and 37 Vietnamese Pot-bellied pigs in Catalonia during the pandemic period (2020-2023).

RESULTS

All the animals tested for acute SARS-CoV-2 infection (232 rodents and 29 wild boar) were negative. For SARS-CoV-2 exposure, 3 out of 313 (0.96%) wild boar tested positive by ELISA, while the remaining 32 rodents, 310 wild boar, and 37 Vietnamese Pot-bellied pigs were all negative. Cross-reactivity with other CoVs was predicted for ELISA-positive samples, as the 3 wild boar tested negative by the virus neutralization assay, considered as the gold standard technique.

CONCLUSIONS

The absence of SARS-CoV-2 exposure or acute infection in wild boar and rodent species supports their negligible role in viral spread or transmission during the COVID-19 pandemic in Catalonia. However, their proximity to humans and the ongoing genetic evolution of SARS-CoV-2 underline the need for continued monitoring. Surveillance of SARS-CoV-2 infection in animal species can contribute to design measures to control the emergence of new animal reservoirs or intermediate hosts that could facilitate viral spillover events.

Parasitological Examination of the Digestive System of Wild Boar from a Practical Point of View-Endoparasitological Sampling under Field Conditions

From 2015 to 2023, we conducted a comprehensive study in the 11,893-hectare hunting area managed by the Marcal-Bitvaközi Hunting Company, characterised by its substantial wild boar population. The research was carried out across various settings, including a free-range wild boar garden during large-scale hunts and free-living areas during individual hunts. We examined 216 wild boars in total, with 173 individuals from free-living areas and 43 from free-range areas. Throughout the sample collection process, we encountered numerous technical challenges that are infrequently detailed in the professional literature, often mentioned only tangentially. This oversight in existing publications neglects the significance of addressing field sampling difficulties, which are crucial for ensuring the precision and accuracy of research. This paper details the equipment requirements, sampling methodologies, and practical solutions to streamline fieldwork. While our primary focus was on endoparasitic infections of the stomach and small intestine, the described methodologies and findings are broadly applicable to research involving all internal organs.

Multi-omics analysis of gut microbiota and metabolites reveals contrasting profiles in domestic pigs and wild boars across urban environments

The gut microbiota plays a crucial role in host health and metabolism. This study explores the differences in gut microbiota and metabolites between domestic pigs (DP) and wild boars (WB) in urban environments. We analyzed gut microbial composition, metabolic profiles, virome composition, antibiotic resistance genes (ARGs), and human pathogenic bacteria (HPB) in both DP and WB. Our results revealed that DP exhibited a higher Firmicutes/Bacteroidetes ratio and were enriched in bacterial genera associated with domestication and modern feeding practices. Metabolomic analysis showed distinct profiles, with WB significantly enriched in the Pantothenate and CoA biosynthesis pathway, highlighting dietary and environmental influences on host metabolism. Additionally, DP had a distinct gut virome composition, particularly enriched in lytic phages of the Chaseviridae family. ARG analysis indicated a higher abundance of tetracycline resistance genes in DP, likely due to antibiotic use in pig farms. Furthermore, variations in HPB composition underscored potential health risks associated with contact with pig feces. These findings provide valuable insights into the microbial ecology of domestic pigs and wild boars, emphasizing the importance of these comparisons in identifying zoonotic pathogen transmission pathways and managing antibiotic resistance. Continued research in this area is essential for developing effective strategies to mitigate public health risks and promote sustainable livestock management practices.

Serological and Molecular Survey of Rickettsial Agents in Wild Boars (Sus scrofa) from Midwestern Brazil

Wild boars (Sus scrofa L.) are considered among the most harmful invasive species worldwide, causing irreversible ecosystem damage, acting as zoonotic spreaders and reservoirs, threatening human and animal health, and having an important economic impact. Accordingly, the present study has assessed the rickettsial exposure, tick infestation of wild boars, and rickettsial DNA presence in ticks from infested animals from the Cerrado biome in midwestern Brazil. Anti-Rickettsia spp. antibodies were detected in serum samples of wild boars by immunofluorescence assay. Overall, 106/285 (37.2%) wild boar serum samples from 13 to 18 (72.2%) municipalities showed seroreactivity to at least one of the four Rickettsia spp. antigens tested, the largest number of wild boars serologically tested to Rickettsia spp. in this type of study. Among the 106 seroreactive animals, 34 showed possible homologous reactions between R. parkeri, R. amblyommatis, and R. bellii, with endpoint titers between 128 and 512. A sample of 45 ticks collected from four culled wild boars was identified as Amblyomma sculptum, and all tested negative for rickettsial DNA presence. In conclusion, this study has provided a reliable sampling seroprevalence and indicated high exposure of wild boars to rickettsial agents, with a potential interaction with Rickettsia spp. from the spotted fever group within the Cerrado biome from midwestern Brazil.

Assessment of domestic pig-bushpig (Potamochoerus larvatus) interactions through local knowledge in rural areas of Madagascar

In many parts of the world, domestic and wild animal populations interact at the interface between natural and agricultural ecosystems. Introduced with the first inhabitants arriving from eastern Africa, the bushpig (Potamochoerus larvatus) is the largest living terrestrial mammal in Madagascar. Bushpigs are regularly reported close to human settlements where they damage crops and gardens. As domestic pigs are often raised in free-ranging conditions around the villages, bushpigs and domestic pigs can interact leading to the transmission and circulation of shared swine pathogens that impact both animal and human health. In this study, we characterized the socio-ecological context of bushpig-domestic pig interactions in two different regions of western Madagascar. We conducted participatory mapping sessions and focus group interviews with 65 hunters, 80 pig farmers and 96 crop farmers in 20 fokontany, the smallest administrative unit in Madagascar. After discussing with participants, we gathered information about the spatialization of interactions and their potential geographical drivers. We explored data by performing multiple correspondence analysis and hierarchical clustering on principal components. Based on the reported occurrence or absence of bushpig-domestic pig interactions we were able to classify areas with high or intermediate levels of interactions or no interactions at all. Interactions between the two pig species were reported in only 25% of the fokontany assessed. Even though both suid species were attracted to fruit trees, crops, and water sources, only indirect interactions in those spots were reported. Direct interactions were reported in 10% of cases and referred to interspecific sexual and/or agonistic behavior. The participatory methods used to acquire local knowledge about natural events were confirmed as valuable, low-cost exploratory methods to characterize areas with wild-domestic animal interactions. The results of this study will help plan future studies to characterize the interface between the two species from an ecological or epidemiological perspective using more sensitive and sophisticated ecological approaches.

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.

Large-Scale Serological Survey of Influenza A Virus in South Korean Wild Boar (Sus scrofa)

In this comprehensive large-scale study, conducted from 2015 to 2019, 7,209 wild boars across South Korea were sampled to assess their exposure to influenza A viruses (IAVs). Of these, 250 (3.5%) were found to be IAV-positive by ELISA, and 150 (2.1%) by the hemagglutination inhibition test. Detected subtypes included 23 cases of pandemic 2009 H1N1, six of human seasonal H3N2, three of classical swine H1N1, 13 of triple-reassortant swine H1N2, seven of triple-reassortant swine H3N2, and seven of swine-origin H3N2 variant. Notably, none of the serum samples tested positive for avian IAV subtypes H3N8, H5N3, H7N7, and H9N2 or canine IAV subtype H3N2. This serologic analysis confirmed the exposure of Korean wild boars to various subtypes of swine and human influenza viruses, with some serum samples cross-reacting between swine and human strains, indicating potential infections with multiple IAVs. The results highlight the potential of wild boar as a novel mixing vessel, facilitating the adaptation of IAVs and their spillover to other hosts, including humans. In light of these findings, we recommend regular and frequent surveillance of circulating influenza viruses in the wild boar population as a proactive measure to prevent potential human influenza pandemics and wild boar influenza epizootics.

Molecular detection of ovine gammaherpesvirus 2 in free ranging wild boars (Sus scrofa) from Southern Brazil

Ovine gammaherpesvirus 2 (OvGHV2) is a member of Macavirus genus, subfamily Gammaherpesvirinae, family Herpesviridae, and causes sheep associated-malignant catarrhal fever (SA-MCF) in a wide range of ungulates. However, no descriptions of SA-MCF and/or infections due to OvGHV2 were identified in the wild boar (Sus scrofa). This study investigated the occurrence of OvGHV2 in the lungs (n = 44) of asymptomatic, free ranging wild boars captured in several regions of Paraná State, Southern Brazil. A PCR assay targeting the OvGHV2 tegument protein gene amplified OvGHV2 DNA in 4.55% (2/44) of the pulmonary tissues evaluated. Sequence analysis confirmed that the OvGHV2 strains herein identified have 98.4% deduced amino acid (aa) sequence identity with the prototype strain of OvGHV2 and 96.4-100% aa identity with similar strains of OvGHV2 detected in several animal species from diverse countries. These findings confirmed that these two wild boars were infected by OvGHV2, represent the first description of this infection in these animals, and add to the number of pathogens identified in this animal species. Furthermore, these findings contrast earlier descriptions of OvGHV2 in swine since in all previous reports the infected pigs demonstrated clinical manifestations of disease. Consequently, these wild boars from Southern Brazil were subclinically infected or suffered asymptomatic infections by OvGHV2.

Seroprevalence study of brucellosis in wild boar hunted for private consumption in northeast Portugal

Brucellosis is an important infectious disease caused by bacteria of the genus Brucella. In the northeast region of Portugal, infection with Brucella melitensis is endemic in small ruminants, and there are also humans' cases. However, the epidemiological role of the wild boar in the dynamics of this disease in this region is unknown. In this study, a total of 332 blood samples were collected from wild boar hunted in thirty-six hunting areas during the 2022/2023 hunting season. All were taken by the hunters for private consumption, with no evisceration or examination in the field. Serum samples were tested by indirect ELISA (i-ELISA). It was observed that 88 wild boars were exposed to Brucella spp., pointing to a seroprevalence of 26.5% (95% CI: 21.8 - 31.3%). This high prevalence underlines the importance that wild boar may have in the dynamics of this disease in the region and its potential transmission to other animals, and to humans (for example, during the handling of carcasses). Increased awareness and knowledge of brucellosis in wild boar is essential for the implementation of effective practices and habits and, consequently, for the control and prevention of this important zoonosis.

Prevalence of Paslahepevirus balayani in commercial swine food products from Spain

Paslahepevirus balayani (formerly known as hepatitis E virus) is an emerging cause of foodborne disease in Europe, transmitted mainly by the consumption of raw or undercooked pork. Since little is known about the presence of the virus in several pork products that are eaten uncooked, our aim was to evaluate the prevalence of Paslahepevirus balayani in groups of commercial pork products intended for human consumption subjected to different processing techniques. A total of 1265 samples of pork products from Spain were divided into four groups and tested for the presence of Paslahepevirus balayani RNA: unprocessed pig and wild boar meat frozen at -20 °C (n = 389), dry-cured pork products (n = 391), dry-cured and salted pork products (n = 219), and boiled products (n = 266) (none of these products contained pork liver). Five samples were positive for Paslahepevirus balayani RNA (overall prevalence: 0.4%; 95% CI: 0.17% - 0.92%). All positive samples were from unprocessed meat stored at -20 °C, with a prevalence in this group of 1.3% (95% CI: 0.42-3.44); two samples came from pigs (1.1%; 95% CI: 0.13-3.81) and three from wild boar (1.5%; 95% CI: 0.31-4.28). None of the pork samples in the other groups was positive. In conclusion, Paslahepevirus balayani was found in unprocessed swine products form Spain, but not in processed products intended to be consumed undercooked, demonstrating that transmission of this zoonotic virus by eating these pork products should be more seriously considered.

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.

Identification and phylogenetic analysis of Jingmen tick virus in Jiangxi Province, China

Jingmen tick virus (JMTV) is a newly identified segmented flavivirus that has been recognized in multiple hosts, such as humans, buffalos, bats, rodents, mosquitos and ticks. Various clinical cases and studies manifested that JMTV is a true arbovirus with wide host spectrum and showed potential threats toward public health. JMTV has been reported in multiple countries in Asia, Europe, Africa, and America. Moreover, wild boars serve as an important intermediary between humans and the wild ecological system. In China, it has been reported in nine provinces, while the prevalence and the distribution of JMTV in most regions including Jiangxi Province are still unknown. Thus, to profile the distribution of JMTV in Jiangxi Province, an epidemiological investigation was carried out from 2020 to 2022. In current study, 66 ticks were collected from 17 wild boars in Jiangxi Province. The results showed that 12 out of 66 ticks were JMTV positive, indicating JMTV is prevalent in ticks and boars in Jiangxi Province. The genome sequences of JMTV strain WY01 were sequenced to profile viral evolution of JMTV in China. Phylogenetic analysis divided JMTV strains into two genotypes, Group I and Group II. WY01 belongs to Group II and it shares the closest evolutionary relationship with the Japan strains rather than the strains from neighboring provinces in China suggesting that JMTV might have complex transmission routes. Overall, current study, for the first time, reported that JMTV is prevalent in Jiangxi Province and provided additional information concerning JMTV distribution and evolution in China.

A combined methodological approach to characterize pig farming and its influence on the occurrence of interactions between wild boars and domestic pigs in Corsican micro-regions

The pig sector in Corsica is based by a wide range of farming systems, mainly characterized on traditional extensive practices, which favor contacts between domestic and wild individuals. These contacts are suspected to influence the maintenance and the transmission of shared infectious diseases between both populations. Therefore, it is important to develop methods that allow to understand and anticipate their occurrence. Modeling these interactions requires accurate data on the presence, location and use of land on pig farms and farming practices, but such data are often unavailable, incomplete or outdated. In this study, we suggest a method to collect and analyze pig farming information that combines approaches from social sciences and epidemiology and enables a spatial representation of an index of potential interaction (IPI) between wild and domestic pigs at municipality level in the Corsican territory. As a first step of the process, interviews were conducted to gather information from 103 pig farms. Then, using hierarchical clustering, we identified five different clusters of pig farming practices which were evaluated and validated by local experts using participatory tools. The five pig farming clusters with their respective estimated levels of direct and indirect interactions with wild boars were combined in a linear equation with pig density to estimate a hypothetical index of potential interaction (IPI) in 155 municipalities. Our results revealed the diversity of pig farming practices across the island of Corsica and pointed out potential hotspots of interaction. Our method proved to be an effective way to collect and update information on the presence and typology of pig farms which has the potential to update official livestock production statistics. The spatial representation of an IPI between wild boars and domestic pigs in the Corsican territory could help design regional disease management strategies and policies to improve the control of certain shared pig pathogens in pig farms from Corsica.

Study on the relationship between the dispersal of wild boar (Sus scrofa) and the associated variability of Cesium-137 concentrations in its muscle Post-Fukushima Daiichi Nuclear Power Plant accident

After the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in 2011, the wild boar (Sus scrofa) population within the Fukushima Evacuation Zone (FEZ) increased substantially in size and distribution. This growing population and their potential dispersal from the FEZ, where they are exposed to high levels of radionuclides, into the surrounding landscape underscores the need to better understand boar movement patterns in order to establish policies for managing shipping restrictions for boar meat and develop management strategies. In this study, we quantified the genetic population structure of boar in and around Fukushima prefecture using sequence data of the mitochondrial DNA control region and MIG-seq analysis using 348 boar samples to clarify boar dispersal patterns. Among boar samples, seven Asian haplotypes and one European haplotype were detected. The European haplotype originated from hybridization between domestic pigs and native boar in the evacuation zone after the accident and was detected in 15 samples across a broad geographic area. Our MIG-seq analysis revealed genetic structure of boar was significantly different between boar inhabiting the eastern (including FEZ. i.e., East clade) and western (i.e., West clade) regions in Fukushima prefecture. In addition, we investigated the relationships between boar dispersal and Cesium (Cs)-137 activity concentrations in boar muscle using MIG-seq genetic data in Nihonmatsu city, located in the central-northern region of Fukushima. High Cs-137 activity concentrations, exceeding 1000 Bq/kg, in boar muscle had a significantly high probability of belonging to the East clade within localized regions. Thus, our results provide evidence of the spatial scale of dispersal of individuals or offspring of boar from the FEZ. Results of this research also indicate that dispersal of individuals between areas with different Cs-137 contamination levels is one of the biggest factors contributing to variation in Cs-137 activity concentration in boar muscle within localized regions.

Serosurveillance of Trichinella sp. in wild boar and Iberian domestic suids in Mediterranean ecosystems of southwestern Spain

AIMS

A cross-sectional study was carried out to assess the seroprevalence and risk factors associated with Trichinella spp. exposure in wild boar and Iberian domestic pigs from Mediterranean ecosystems of southwestern Spain.

METHODS AND RESULTS

Serum samples from 1360 wild boar and 439 Iberian domestic pigs were obtained during 2015-2020, from regions where Iberian pigs are raised under extensive conditions, hence sharing habitat with wild boar. Seropositivity was found in 7.4% (100/1360; 95% CI: 6.1-8.9) of the wild boar analysed. In this species, the individual seroprevalence ranged from 3.6% (8/223) (hunting season 2016-2017) to 11.4% (37/326) (2018-2019). A significant higher seropositivity was observed during the hunting season 2018-2019 (p < 0.009: OR = 3.07; 95% CI = 1.32-7.18) and one statistically significant cluster was detected within the studied area, in south central Andalusia [Relative Risk (RR) = 2.9; p = 0.037]. Females showed a significantly higher seroprevalence than males (8.7% vs. 5.8%) (p < 0.001: OR = 1.58; 95% CI = 1.08-2.32). No seropositivity to Trichinella spp. was detected in Iberian domestic pigs (0.0%; 95% CI: 0.0-0.9).

CONCLUSIONS

Although wild boar play an important role as a reservoir of Trichinella sp. in the Mediterranean ecosystems of southwestern Spain, our results suggest that the wild boar production system does not seem to pose a risk of Trichinella exposure to domestic pigs, despite sharing habitats in these ecosystems.

Tuberculosis in Wild Pigs from Argentina

Mycobacterium bovis, a member of the Mycobacterium tuberculosis complex (MTC) and non-tuberculous Mycobacteria (NTM), may infect wild and domestic mammals, including humans. Although cattle are the main hosts and spreaders of M. bovis, many wildlife hosts play an important role worldwide. In Argentina, wild boar and domestic pigs are considered important links in mammalian tuberculosis (mTB) transmission. The aim of this work was to investigate the presence of M. bovis in wild pigs from different regions of Argentina, to characterize isolates of M. bovis obtained, and to compare those with other previously found in vertebrate hosts. A total of 311 samples from wild pigs were obtained, and bacteriological culture, molecular identification and genotyping were performed, obtaining 63 isolates (34 MTC and 29 NTM). Twelve M. bovis spoligotypes were detected. Our findings suggest that wild pigs have a prominent role as reservoirs of mTB in Argentina, based on an estimated prevalence of 11.2 ± 1.8% (95% CI 8.0-14.8) for MTC and the frequency distribution of spoligotypes shared by cattle (75%), domestic pigs (58%) and wildlife (50%). Argentina has a typical scenario where cattle and pigs are farm-raised extensively, sharing the environment with wildlife, creating conditions for effective transmission of mTB in the wildlife-livestock-human interface.

Diversity of astroviruses in wild animals in Yunnan province, China

BACKGROUND

Astroviruses (AstVs) are single-stranded RNA viruses that have been detected in a wide range of mammals and birds. They are associated with numerous interspecies transmissions and viral recombination events, posing a threat to human and animal health.

METHODS

We collected 1,333 samples from wild animals, including bats, rodents, wild boars, and birds, from various states and cities in the Yunnan Province, China, between 2020 and 2023 to investigate the presence of AstVs. AstVs were detected using a polymerase chain reaction targeting the RdRp gene. Finally, the Molecular Evolutionary Genetics Analysis software was used to construct the phylogenetic tree.

RESULTS

The overall positivity rate for AstVs was 7.12% in four species, indicating their widespread occurrence in the region. High genetic diversity among AstVs was observed in different animal species, suggesting the potential for interspecies transmission, particularly among rodents and birds. Additionally, we identified a novel AstV strain and, for the first time, provided information on the presence of bastroviruses in Yunnan, China.

CONCLUSIONS

The widespread distribution and high genetic diversity of AstVs, along with the observed potential for interspecies transmission, highlight the importance of further investigation and surveillance in the region. The findings emphasize the need for increased attention to AstVs and their potential impact on human and animal health in Yunnan and other regions.

Porcine Epidemic Diarrhea Virus: Etiology, Epidemiology, Antigenicity, and Control Strategies in China

Porcine epidemic diarrhea virus (PEDV) is a porcine enteric coronavirus, which is one of the main causative agents of porcine epidemic diarrhea (PED), with 100% morbidity and 80-100% mortality in neonatal piglets. Since 2010, large-scale PED caused by highly pathogenic variants of PEDV has occurred successively in China and other countries in the world, posing a great threat to the global pig industry. It has been demonstrated in many investigations that the classic attenuated vaccine strain, PEDV CV777, is insufficient to fully protect against the PEDV variants. Moreover, the maternally derived antibodies elicited by inactivated vaccines also cannot completely protect piglets from infection. In addition, feedback feeding poses a risk of periodic PEDV recurrence in pig farms, making it challenging to successfully limit the spread of PEDV in China. This review focuses on the etiology, epidemiology, antigenicity, and control strategies of PEDV in China and provides information for the formulation of effective control measures.

Mortality and heavy metals environmental exposure: a study in dogs

Introduction

Dogs are human companions and share environmental conditions with their owners. Epidemiological studies have shown that dogs seem to be good sentinel animals for the association of diseases and/or mortality provoked by chronic exposure to heavy metals (Cd, Pb).

Methods

In the present work, we analyze the registered death cases and population from the National Canine Registry from 2020 to 2022, involving a dog population of 582,564 and 17,507 deaths. The mortality rate in male and not-purebred dogs is higher than in female and purebred dogs, respectively. The mortality cases were cross-referenced with the environmental pollution data relating to the concentration of Cd and Pb detected, between 2012 and 2022, in the various municipalities of the Liguria region. We then calculated SMR (Standardized Mortality Rate) throughout the region and found that mortality increases from the eastern to the western Ligurian coast.

Results and discussion

We observed that the most polluted areas present the highest SMRs (IRR = 1.36, 95%CI: from 1.31 to 1.41). Considering dog ages, we found that mortality in young dogs is not affected by pollution, while mortality in old dogs (10-20 years old) is heavily affected by it (IRR = 8.97, 95%CI from 8.09 to 9.93). In conclusion, the data suggest the importance of canine health and biomonitor studies and provide a basis for future research involving both animal and human health.

Coexistence of roof rats and carnivores in barns on a livestock farm in Japan

Brown rats (Rattus norvegicus), roof rats (Rattus rattus), and house mice (Mus musculus) are considered to be important pests on livestock farms. Although the diel activity patterns of rodents are key to their control, information on this aspect of their ecology is limited. Furthermore, the effect of carnivores on rodent activity patterns as well as the carnivore species present on livestock farms is unclear. Here, we set camera traps in an open-type cow barn and in an enclosed pig barn on the same livestock farm in Japan from August through October 2021. The only rodents observed in both barns were roof rats, and the carnivore species observed were dogs (Canis familiaris), cats (Felis catus), and Japanese weasels (Mustela itatsi). Roof rats showed different patterns of activity and behavior between the barns. However, because the pattern in both barns was nocturnal, the activity patterns of roof rats and carnivores showed a moderate to high degree of overlap. Therefore, roof rats did not appear to shift their activity patterns to avoid nocturnal carnivores. Taken together, the present study provides valuable information for rodent control on livestock farms in Japan.

Distribution and prevalence of antibodies to Trichinella spp. and Toxoplasma gondii in wild pigs (Sus scrofa) in the United States

Invasive wild pigs (Sus scrofa) are a reservoir for over 100 viral, bacterial, and parasitic pathogens that are transmissible to humans, livestock, domestic animals, and wildlife in North America. Numerous historical local surveys and results from a nation-wide survey (2006-2010) indicated that wild pigs in the United States act as reservoirs for Trichinella spp. and Toxoplasma gondii, two zoonotic pathogens of importance for human and animal health. Since that time, wild pig populations have expanded and increased in density in many areas. Population expansion of wild pigs creates opportunities for the introduction of pathogens to new areas of the country, increasing health risks. The goal of this study was to investigate the current geographic distribution and prevalence of Trichinella spp. and T. gondii antibodies in wild pigs using serum samples collected from 2014 to 2020. Serum samples from 36 states were tested for antibodies to Trichinella spp. (n = 7467) and T. gondii (n = 5984) using commercially available enzyme-linked immunosorbent assays. Seroprevalence for Trichinella spp. (12.4%, 927/7467) and T. gondii (40.8%, 2444/5984) are significantly higher compared to a previous 2006-2010 study across all regions. Results from this study also showed a lower seroprevalence (4.8%) for Trichinella spp. in the West region compared to the other regions (South: 13.4%; Midwest: 18.4%; Northeast: 19.1%). There were new detection records for antibodies to Trichinella spp. in 11 states, mostly in the West, Midwest, and Northeast regions compared to a previous study in 2014. Males and juveniles were less likely to be positive for Trichinella spp. antibodies, compared to females and older animals, respectively. Seroprevalence was similar for T. gondii across the regions (31.8-56%) with some states having particularly high seroprevalence (e.g., Hawaii 79.4% and Pennsylvania 68%). There were new T. gondii antibody detection records for 12 states, mostly in the West, Midwest, and Northeast regions. Adults were more likely than juveniles and subadults to be seropositive. These data confirm that the distribution and prevalence of antibodies for Trichinella spp. and T. gondii are increasing in the United States, likely driven by wild pig population growth and range expansion.

Changes in wild pig (Sus scrofa) relative abundance, crop damage, and environmental impacts in response to control efforts

BACKGROUND

As the population and range of wild pigs (Sus scrofa) continue to grow across North America, there has been an increase in environmental and economic damages caused by this invasive species, and control efforts to reduce damages have increased concomitantly. Despite the expanding impacts and costs associated with population control of wild pigs, the extent to which wild pig control reduces populations and diminishes environmental and agricultural damages are rarely quantified. The goal of this study is to quantify changes in wild pig relative abundance and subsequent changes in damages caused by invasive wild pigs in response to control.

RESULTS

Using a combination of wild pig population surveys, agricultural damage assessments, and environmental rooting surveys across 19 mixed forest-agricultural properties in South Carolina, USA, we quantified changes in wild pig relative abundance and associated damages over a 3-year period following implementation of a professional control program. Following implementation of control efforts, both the number of wild pig detections and estimated abundance decreased markedly. Within 24 months relative abundance was reduced by an average of ~70%, which resulted in a corresponding decline in environmental rooting damage by ~99%.

CONCLUSION

Our findings suggest that sustained wild pig control efforts can substantially reduce wild pig relative abundance, which in turn resulted in a reduction in environmental rooting damage by wild pigs. Ultimately this study will help fill critical knowledge gaps regarding the efficacy of wild pig control programs and the effort needed to reduce impacts to native ecosystems, livestock, and crops. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Assessing the epidemiological risk at the human-wild boar interface through a one health approach using an agent-based model in Barcelona, Spain

Wild boar (WB, Sus scrofa) populations are increasing in urban areas, posing an epidemiological risk for zoonotic pathogens such as hepatitis E virus (HEV) and antimicrobial-resistant Campylobacter (AMR-CAMP), as well as non-zoonotic pathogens such as African swine fever virus (ASFV). An epidemiological extension of a validated Agent-Based Model (ABM) was developed to assess the one-year epidemiological scenarios of HEV, AMR-CAMP, and ASFV in the synurbic WB-human interface in Barcelona, Spain. The predicted citizen exposure was similar for HEV and AMR-CAMP, at 0.79% and 0.80% of the human population in Barcelona, respectively, despite AMR-CAMP being more prevalent in the WB population than HEV. This suggests a major role of faeces in pathogen transmission to humans in urban areas, resulting in a non-negligible public health risk. The ASFV model predicted that the entire WB population would be exposed to the virus through carcasses (87.6%) or direct contact (12.6%) in 51-71 days after the first case, with an outbreak lasting 71-124 days and reducing the initial WB population by 95%. The ABM predictions are useful for animal and public health risk assessments and to support risk-based decision-making. The study underscores the need for interdisciplinary cooperation among animal, public, and environmental health managers, and the implementation of the One Health approach to address the epidemiological and public health risks posed by the synurbization of WB in urban areas. The spatially explicit epidemiological predictions of the ABM can be adapted to other diseases and scenarios at the wildlife-livestock-human interface.

One Health at gunpoint: Impact of wild boars as exotic species in Brazil - A review

Wild boars have been listed among the 100 most invasive species worldwide, spreading impacts to all continents, with the exception of Antarctica. In Brazil, a major source of introduction was a commercial livestock importation for exotic meat market, followed by successive escapes and releases to natural ecosystems. Currently found in all six Brazilian biomes, with reports in 11 Brazilian states, wild boars have invaded natural and agricultural areas. Wild boars have been reportedly indicated as hosts and reservoirs of several zoonotic diseases in Brazil, including toxoplasmosis, salmonelosis, leptospirosis, brucellosis, tuberculosis, trichinellosis, and hepatitis E. Wild boars have been also associated with Brazilian spotted fever and rabies, infected while providing plentiful exotic blood supply for native ticks and hematophagous bats. Due to their phylogenetic proximity, wild boars may present ecological niche overlapping and direct disease risk to native white-lipped and collared peccaries. Moreover, wild boars may post an economical threat to Brazilian livestock industry due to restrictive diseases such as Aujeszky, enzootic pneumonia, neosporosis, hemoplasmosis, and classic swine fever. Finally, wild boars have directly impacted in environmentally protected areas, silting up water springs, rooting and wallowing native plants, decreasing native vegetal coverage, disbalancing of soil components, altering soil structure and composition. Wild boar hunting has failed as a control measure to date, according to the Brazilian Ministry of Environment, due to private hunting groups mostly targeting males, intentionally leaving females and piglets alive, disseminating wild boar populations nationwide. Meanwhile, non-government animal welfare organizations have pointed to animal cruelty of hunting dogs and wild boars (and native species) during hunting. Despite unanimous necessity of wild boar control, eradication and prevention, methods have been controversial and should focus on effective governmental measures instead occasional game hunting, which has negatively impacted native wildlife species while wild boars have continuously spread throughout Brazil.

Generation of porcine PK-15 cells lacking the Ifnar1 or Stat2 gene to optimize the efficiency of viral isolation

Because pigs are intermediate or amplifying hosts for several zoonotic viruses, the pig-derived PK-15 cell line is an indispensable tool for studying viral pathogenicity and developing treatments, vaccines, and preventive measures to mitigate the risk of disease outbreaks. However, we must consider the possibility of contamination by type I interferons (IFNs), such as IFNα and IFNβ, or IFN-inducing substances, such as virus-derived double-stranded RNA or bacterial lipopolysaccharides, in clinical samples, leading to lower rates of viral isolation. In this study, we aimed to generate a PK-15 cell line that can be used to isolate viruses from clinical samples carrying a risk of contamination by IFN-inducing substances. To this end, we depleted the IFN alpha and beta receptor subunit 1 (Ifnar1) gene or signal transducer and activator of transcription 2 (Stat2) gene in PK-15 cells using the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 method. Treatment of PK-15 cells lacking Ifnar1 or Stat2 with IFNβ or poly (I:C) resulted in no inhibitory effects on viral infection by a lentiviral vector, influenza virus, and Akabane virus. These results demonstrate that PK-15 cells lacking Ifnar1 or Stat2 could represent a valuable and promising tool for viral isolation, vaccine production, and virological investigations.

Prevalence and Risk Factors for Hepatitis E Virus in Wild Boar and Red Deer in Portugal

Hepatitis E virus (HEV) is a zoonotic foodborne virus with an annual infection prevalence of 20 million human cases, which seriously affects public health and economic development in both developed and developing countries. To better understand the epidemiology of HEV in Central Portugal, a cross-sectional study was conducted from 2016 to 2023 with sera samples from wild ungulates. The seroprevalence and risk factors for HEV seropositivity were evaluated in the present study. Specifically, antibodies against HEV were determined by a commercial enzyme-linked immune-sorbent assay (ELISA). Our results show that in the 650 sera samples collected from 298 wild red deer and 352 wild boars in Portugal, 9.1% red deer and 1.7% wild boar were positive for antibodies to HEV. Regarding age, the seropositivity in juvenile wild ungulates was 1.3%, whereas it was 7.2% in adults. Logistic regression models investigated risk factors for seropositivity. The odds of being seropositive was 3.6 times higher in adults than in juveniles, and the risk was 4.2 times higher in red deer than in wild boar. Both wild ungulate species were exposed to HEV. The higher seroprevalence in red deer suggests that this species may make a major contribution to the ecology of HEV in Central Portugal. Further research is needed to understand how wildlife affects the epidemiology of HEV infections in Portugal.

Spatiotemporal Patterns of African Swine Fever in Wild Boar in the Russian Federation (2007-2022): Using Clustering Tools for Revealing High-Risk Areas

African swine fever (ASF) is an infectious disease that affects both domestic pigs (DPs) and wild boar (WB). The WB population plays an important role in the spread of ASF as the WB acts as a natural reservoir of the virus and transmits it to other susceptible wild and domestic pigs. Our study was aimed at revealing the areas with a high concentration of the WB population, and their potential relationships with the grouping of ASF cases in WB during the course of the ASF spread in the Russian Federation (2007-2022). We collected the annual data on WB numbers by municipalities within the regions of the most intensive ASF spread. We then conducted spatiotemporal analysis to identify clustering areas of ASF cases and compare them with the territories with a high density of WB population. We found that some of the territories with elevated ASF incidence in WB demonstrated spatial and temporal coincidence with the areas with a high WB population density. We also visualized the zones ("emerging hot spots") with a statistically significant rise in the WB population density in recent years, which may be treated as areas of paramount importance for the application of surveillance measures and WB population control.

Epizootiological surveillance of porcine circoviruses in free-ranging wild boars in China

Four species of porcine circoviruses (PCV1-4) have been reported to circulate in Chinese domestic pigs, while the epizootiology of these viruses in free-ranging wild boars in China remains unknown. In this study, tissue and serum samples collected from diseased or apparently healthy wild boars between 2018 and 2020 in 19 regions of China were tested for the prevalence of PCV1-4 infections. Positive rates of PCV1, PCV2, and PCV3 DNA in the tissue samples of Chinese wild boars were 1.6% (4/247), 58.3% (144/247), and 10.9% (27/247) respectively, with none positive for PCV4. Sequence analysis of viral genome showed that the four PCV1 strains distributed in Hunan and Inner Mongolia shared 97.5%-99.6% sequence identity with global distributed reference strains. Comparison of the ORF2 gene sequences showed that 80 PCV2 strains widely distributed in 18 regions shared 79.5%-100% sequence identity with reference strains from domestic pigs and wild boars, and were grouped into PCV2a (7), PCV2b (31) and PCV2d (42). For PCV3, 17 sequenced strains shared 97.2%-100% nucleotide identity at the genomic level and could be divided into PCV3a (3), PCV3b (2) and PCV3c (12) based on the phylogeny of ORF2 gene sequences. Serological data revealed antibody positive rates against PCV1 and PCV2 of 11.4% (19/167) and 53.9% (90/167) respectively. The data obtained in this study improved our understanding about the epidemiological situations of PCVs infection in free-ranging wild boars in China and will be valuable for the prevention and control of diseases caused by PCVs infection.

Detection of porcine circovirus 2, porcine parvovirus 1, and torque teno sus virus k2a in wild boars from northeastern Patagonia, Argentina

Wild boars can act as a reservoir of pathogenic viruses that affect the pig industry. Here, we assessed the presence of porcine circovirus 2, porcine parvovirus 1, and torque teno sus virus k2a in wild boars in northeastern Patagonia (Argentina). Total DNA was extracted from the tonsils of 27 animals (collected between early 2016 and mid-2019) and used to prepare sample pools, which were subjected to viral detection through two-round PCR assays. Sequencing of the amplification products and phylogenetic analysis confirmed the occurrence of all of the aforementioned infectious agents.

Unregulated Online Sales are High-Risk Sources of Domestic Swine (Sus scrofa) in Canada: Implications for Invasive Wild Pig and AfricanSwine Fever Risk Preparedness

Free-ranging wild pig (Sus scrofa) populations may cause widespread environmental damage and transmit diseases at the wildlife-livestock interface. For example, African swine fever (ASF) is a highly contagious viral disease of pigs capable of causing catastrophic economic losses. Prevention and preparedness for ASF require understanding wild and domestic pig movements and distribution. We characterized a "grey" swine market and described the risks it poses, contributing to the threats associated with wild pig populations. We monitored www.kijiji.ca, a Canadian internet classified advertising service, for sales of domestic wild boar, pot-bellied pigs, other breeds, and their hybrids across Canada from 28 April to 30 June 2021. Data collected included seller-defined breed, age, sex, number for sale, sexual intactness, presence of identifying tags or tattoos, and the date and location of listings. Advertisement locations were mapped and compared with existing wild pig distributions, identifying areas new populations might be established, and existing populations supplemented or genetically diversified. We identified 151 advertisements on Kijiji: 34% (n=52/151) from Ontario, 29% (n=44/151) from Alberta, 41% (n=62/151) from existing wild pig populations, and 59% (n=89/151) from areas where wild pigs have not yet been identified. We propose requiring the use of individual animal identifiers (tags/tattoos), genetic analysis, and mandatory reporting for all pig sales in Canada to aid in ASF preparedness and to increase regulation and enforcement of the online swine market.

Gastrointestinal parasites of zoonotic importance detected in porcine faeces in Chitwan National Park, Nepal

Wild boar (Sus scrofa) is considered to be a potential source of zoonotic parasites. Wild boars are found at considerable number in and around the Chitwan National Park (CNP). The information regarding their intestinal parasites is limited. A cross-sectional study was carried out to determine the prevalence of gastrointestinal parasites in wild boars in CNP. A total of 100 fresh fecal samples were subjected to microscopic examination using direct smear, floatation and sedimentation method. Overall, 95% fecal samples were found positive for at least one parasite. Prevalence of protozoan parasites was found comparatively higher (70%) followed by nematode (56%) and trematode (12%). Nine gastrointestinal parasites such as Eimeria sp. (70% without micropyle and 40% with micopyle), Fasciola sp. (12%), Strongyloides sp. (56%), strongyle-type nematodes (49%), Stephanurus sp. (44%), Globocephalus sp. (38%), Metastrongylus sp. (12%), Ascaris sp. (7%) and Trichuris sp. (6%). were recorded. Eimeria sp. exhibited the highest prevalence while Trichuris had the least prevalence. This study has provided baseline information regarding the diversity of gastrointestinal parasites in wild boars. It requires continuous study at molecular level to explore other species of parasites and verify their zoonotic potential.

Graphical abstract

Eleven Years of Health Monitoring in Wild Boars (Sus scrofa) in the Emilia-Romagna Region (Italy)

In recent years, the growth of wild ungulates has increased the focus on their health monitoring. In particular, the health status of wild boars is relevant for the economic impact on the pig industry. The Emilia-Romagna region activated a wildlife monitoring plan to better evaluate the health status of the wild boar population. Between 2011 and 2021, samples of found dead and hunted wild boar have been examined for trichinellosis, tuberculosis, brucellosis, african swine fever, classical swine fever, Aujeszky's disease, swine vesicular disease, and swine influenza A. Trichinella britovi was identified in 0.001% of the examined wild boars; neither M. bovis nor M. tuberculosis were found in M. tuberculosis complex positive samples; 2.3% were positive for Brucella suis; 29.4% of the sera were positive for Aujeszky's disease virus; and 0.9% of the samples were positive for swine influenza A virus. With an uncertain population estimate, the number of animals tested, the number of positives, and the sampling method do not allow us to make many inferences but suggest the need to implement and strengthen the existing surveillance activity, as it seems to be the only viable alternative for safeguarding animal and human health.

Presence of Foodborne Bacteria in Wild Boar and Wild Boar Meat-A Literature Survey for the Period 2012-2022

The wild boar is an abundant game species with high reproduction rates. The management of the wild boar population by hunting contributes to the meat supply and can help to avoid a spillover of transmissible animal diseases to domestic pigs, thus compromising food security. By the same token, wild boar can carry foodborne zoonotic pathogens, impacting food safety. We reviewed literature from 2012-2022 on biological hazards, which are considered in European Union legislation and in international standards on animal health. We identified 15 viral, 10 bacterial, and 5 parasitic agents and selected those nine bacteria that are zoonotic and can be transmitted to humans via food. The prevalence of Campylobacter, Listeria monocytogenes, Salmonella, Shiga toxin-producing E. coli, and Yersinia enterocolitica on muscle surfaces or in muscle tissues of wild boar varied from 0 to ca. 70%. One experimental study reported the transmission and survival of Mycobacterium on wild boar meat. Brucella, Coxiella burnetii, Listeria monocytogenes, and Mycobacteria have been isolated from the liver and spleen. For Brucella, studies stressed the occupational exposure risk, but no indication of meat-borne transmission was evident. Furthermore, the transmission of C. burnetii is most likely via vectors (i.e., ticks). In the absence of more detailed data for the European Union, it is advisable to focus on the efficacy of current game meat inspection and food safety management systems.

Snow Metrics as Proxy to Assess Sarcoptic Mange in Wild Boar: Preliminary Results in Aosta Valley (Italy)

The widespread diffusion of the wild boar on the Italian territory and its consistent use for hunting have created the possibility to conduct multiple studies on the pathologies afflicting this ungulate. Nevertheless, in the last two decades, only some pathologies such as classical and African Swine Fever, Tuberculosis, Brucellosis from Brucella suis have benefited from substantial public funding and the consequent great interest from the scientific world, while less attention was addressed to parasitic diseases including sarcoptic mange. Therefore, to fill this gap, the purpose of this study was to contribute to the knowledge of sarcoptic mange in the wild boar population in Aosta Valley in the Northwest of Italy, including sympatric species as foxes. Due to past field surveys, it has been possible to find a possible role of snow metrics in the spread of this pathogen. Even if there are only empirical evidence and the mechanism remain unknown remote sensing analysis considering snow metrics were performed to provide to veterinarians, foresters, biologists, and ecologists new tools to better understand wield board dynamics and join to ordinary tool an instrument to enhance management and planning strategies. The snow metrics (SM) were derived from USGS NASA Landsat 8 L2A retrieved from Theia CNES platform and processed in Orfeo Toolbox LIS extension package. The relationship between SM and the disease spread was tested per each Aosta Valley municipality obtaining LISA maps for each hunting season. The results have showed that this parasite is present in an endemic form even if with rather low prevalence values, equal to 1.2% in the season hunting season 2013/2014, and equal to 7.5% in the hunting season 2014/2015. Moreover, within simultaneous given values of SM, sarcoptic mange seem to find good conditions for spreading.

A Maximum Entropy Species Distribution Model to Estimate the Distribution of Bushpigs on Madagascar and Its Implications for African Swine Fever

Bushpigs (Potamochoerus larvatus) play a major role in the socio-ecosystem of Madagascar, particularly in rural areas. They are largely hunted by rural populations as a major source of income and protein. They can also represent a potential source of pathogens for domestic animals and people. For example, it is hypothesized that bushpigs might compromise African swine fever (ASF) eradication programs by sporadically transmitting the virus to domestic pigs. However, available knowledge on the distribution of bushpigs in Madagascar is limited. In this study, we estimated the distribution of bushpigs on Madagascar using a species distribution model (SDM). We retrieved 206 sightings of bushpigs in Madagascar during 1990–2016 and predicted the distribution by using 37 climatic, geographic, and agricultural/human variables related to the presence of bushpigs and running a presence-background maximum entropy SDM. Our model identified three main areas with a high suitability for bushpigs: in the north, central-western, and east of the island (AUC = 0.84). The main contributors to the model were the vegetation index (51.3%), percentage of land covered by trees (17.6%), and annual averaged monthly precipitation (12.6%). In addition, we identified areas in central Madagascar with a high density of domestic pigs and a high suitability score for bushpigs. These results may help to identify bushpig areas at the interface with domestic pigs to assess the risk of pathogen transmission and to design ecological assessments, wildlife management studies, or targeted surveillance and research studies related to many bushpig-borne pathogens, such as ASF, which is an endemic problem in the country, as well as zoonotic diseases such as cysticercosis and hepatitis E. Our approach could also be extrapolated to other species of wild swine in other countries.

Behavior of Wild Pigs toward Conspecific Carcasses: Implications for Disease Transmission in a Hot, Semiarid Climate

Wild pigs (Sus scrofa) are a prolific, invasive species in the United States of America and act as vectors for many pathogens. An emerging pathogen of concern to the USA is African swine fever (ASF), a deadly viral disease affecting swine that is endemic to Africa and has spread to parts of Europe, Asia, and the Caribbean. ASF affects both wild and domesticated pigs and can be transmitted via several avenues, including interactions between and consumption of dead pigs by their live conspecifics. As wild pigs are considered a serious threat in the transmission of ASF, understanding the behavior of wild pigs towards their dead conspecifics is imperative when considering the transmission of ASF and other diseases in the USA. We placed camera traps at a sample of wild pig carcasses dispatched during four aerial shooting events between November, 2020, and June, 2022, at East Foundation’s San Antonio Viejo Ranch, South Texas. We recorded visitation events to carcasses by live wild pigs and recorded their behavior. Furthermore, we assessed daily carcass decomposition rates by visiting carcass sites without cameras. We found no evidence of cannibalism and recorded live wild pig visitations to only 33% of carcasses before advanced stages of decomposition were reached. Carcass decomposition was rapid (2.5 to 3 days), regardless of season, and the time to the first visitation and investigation of carcasses by live conspecifics was quicker than has been recorded in Europe. We posit that active scavenger guilds at our study site, coupled with high temperatures, result in the rapid decomposition of wild pig carcasses, which reduces opportunities for live wild pigs to interact with them when compared to milder climates. We suggest additional research investigating the persistence of ASF in hot, arid climates and the interactions between live pigs and the skeletonized remains of conspecifics.

Prevalence of Eucoleus garfiai in Wild Boars Hunted at Different Altitudes in the Campania and Latium Regions (Italy)

Recent reports of Eucoleus garfiai in wild boars in southern Italy have highlighted the need for collecting epidemiological data on the presence of this parasite and understanding the role of possible interactions between wild boars, E. garfiai, and the environment. This study analyses, using histopathological and biomolecular techniques, the presence of E. garfiai in tongue samples of wild boars hunted in four provinces of the Campania and Latium regions (Italy), in areas located above and below 900 m above sea level (asl). Histopathological examinations revealed the presence of adults and eggs of nematodes, which were subsequently identified as E. garfiai by biomolecular analysis, in the tongue epithelium. The detection of the parasite was more frequent in samples collected from hunting areas located above 900 m asl than in those collected from areas located below 900 m asl (66.67% vs. 38.09%; p < 0.01). Some species of earthworms are intermediate hosts of E. garfiai and it is well known that earthworms are more present in high quality soils. Therefore, we can suggest that the higher prevalence of E. garfiai at higher altitudes is probably linked to a greater presence of earthworms in the soil, due to its higher quality in these areas.

Coronaviruses: Troubling Crown of the Animal Kingdom

The existence of coronaviruses has been known for many years. These viruses cause significant disease that primarily seems to affect agricultural species. Human coronavirus disease due to the 2002 outbreak of Severe Acute Respiratory Syndrome and the 2012 outbreak of Middle East Respiratory Syndrome made headlines; however, these outbreaks were controlled, and public concern quickly faded. This complacency ended in late 2019 when alarms were raised about a mysterious virus responsible for numerous illnesses and deaths in China. As we now know, this novel disease called Coronavirus Disease 2019 (COVID-19) was caused by Severe acute respiratory syndrome-related-coronavirus-2 (SARS-CoV-2) and rapidly became a worldwide pandemic. Luckily, decades of research into animal coronaviruses hastened our understanding of the genetics, structure, transmission, and pathogenesis of these viruses. Coronaviruses infect a wide range of wild and domestic animals, with significant economic impact in several agricultural species. Their large genome, low dependency on host cellular proteins, and frequent recombination allow coronaviruses to successfully cross species barriers and adapt to different hosts including humans. The study of the animal diseases provides an understanding of the virus biology and pathogenesis and has assisted in the rapid development of the SARS-CoV-2 vaccines. Here, we briefly review the classification, origin, etiology, transmission mechanisms, pathogenesis, clinical signs, diagnosis, treatment, and prevention strategies, including available vaccines, for coronaviruses that affect domestic, farm, laboratory, and wild animal species. We also briefly describe the coronaviruses that affect humans. Expanding our knowledge of this complex group of viruses will better prepare us to design strategies to prevent and/or minimize the impact of future coronavirus outbreaks.

Survey of Zoonotic Diarrheagenic Protist and Hepatitis E Virus in Wild Boar (Sus scrofa) of Portugal

Enteropathogenic parasites and viruses have been frequently reported in swine and can infect a wide range of mammals, including humans. Among the wide variety of parasites infecting swine, diarrhoeagenic protists are among those that cause significant morbidity. Hepatitis E virus (HEV) has also been reported both in domestic pigs and wild boar and is known to have an important public health significance. These agents share the fecal−oral transmission route, but data on their fecal shedding and circulation pathways are still lacking or incomplete. Hence, the aim of the present study was to characterize the presence of microeukaryotes and HEV in the wild boar of Portugal. Wild boar stool samples (n = 144) were obtained during the official hunting seasons (October to February) in 2018/2019, 2019/2020, and 2021/2022 and tested for Cryptosporidium spp., Balantioides coli, Giardia duodenalis, Blastocystis sp., Enterocytozoon bieneusi and HEV by molecular assays, followed by sequencing and phylogenetic analysis. We have detected Cryptosporidium scrofarum (1.4%, 95% CI: 0.2−4.9), B. coli (14.6%, 95% CI: 9.2−21.4), Blastocystis ST5 (29.2%, 95% CI: 21.9−37.2) and HEV genotype 3 (2.8%, 95% CI: 0.7−6.9; subgenotypes 3e and 3m). Co-infections were observed in thirteen animals where two were positive for both HEV and B. coli, one was positive for both C. scrofarum and Blastocystis ST5, and ten were positive for both B. coli and Blastocystis ST5. Giardia duodenalis and E. bieneusi were not detected in the surveyed wild boar population. As far as we know, this is the first report describing protist infections by Cryptosporidium spp., B. coli, and Blastocystis sp., as well as the first identification of the emerging HEV genotype 3m in wild boar of Portugal. The present work shows that potentially zoonotic protozoa and HEV are circulating in wild boar populations in Portugal. Awareness and epidemic-surveillance network implementation measures targeting wild boar are needed to prevent the spread of these pathogenic agents to humans.

Assessing feral swine damage in the western gulf region of Arkansas, Louisiana, and Texas

Feral swine (Sus scrofa) as an invasive species in the U.S. have caused severe damage to natural resources through competing for food resources with domestic livestock and destroying habitat by rooting and wallowing. Given their increased population and wide distribution in the southern U.S., feral swine control is becoming an urgent issue for both natural resource managers and landowners. We conducted a three-state mail survey to examine feral swine damage in Arkansas, Louisiana, and East Texas in the western gulf region in 2021. Our results reveal that feral swine activities like rooting and wallowing can cause severe and widespread damage to agriculture and forestry. Among the most reported and concerned damage by feral swine were crops, pastures, livestock, and loss of land value. Soybean damage was the most important agricultural crop damage in both Arkansas and Louisiana while it was hay, silage, and forage crops in East Texas. In terms of livestock damage, beef cattle and calves were the most common and severe damage in all three states. Average economic loss due to feral swine damage was estimated at $67.13/ha, $42.96/ha, $27.31/ha, and $57.54/ha for landowners in the region who owned cropland, forestland, pastureland, and multiple land types, respectively. Those findings could help both landowners and wildlife management personnel understand the negative societal impact of feral swine, and they could also facilitate the comparison between expected benefits and costs of control programs/options for feral swine in the southern states.