Between conflict and reciprocal habituation: Human-wild boar coexistence in urban areas

Urbanization is an ongoing global environmental change. Wildlife may respond using anthropized environments and resources, which is known as synurbization, creating human-wildlife interactions. Wild boar (Sus scrofa) populations have become common in urban areas, including the metropolitan area of Barcelona. Humans respond to wild boars in urban environments either habituating, with lower conflict perception and higher wild boar acceptance, or sensitizing, with reduced tolerance towards wild boars. Since citizen response influences conflict management, this study analysed the drivers of human responses, which should allow adopting socially-accepted measures to manage synurbic wild boar populations. Interviews to 1956 Barcelona citizens were performed, grouping the response variables to score citizen and urban characteristics, as well as citizen lay-knowledge, emotions, experiences, and perception of wild boar. Five citizen clusters were identified: cluster 1 (3.3 %), highly habituated and active wild boar feeder; cluster 2 (11.3 %), habituated to wild boars with positive feelings; cluster 3 (19.8 %), not habituated nor sensitized, willing to maintain urban wild boar populations; cluster 4 (29.1 %), sensitized and concerned, defending to reduce wild boar; and cluster 5 (40.1 %), highly sensitized and proposing to reduce or even eliminate wild boar. Positive attitudes associated wild boar to aesthetic value, closeness to nature and sympathy, and were more frequent in young citizens with urban background and high education, animal lovers habituated to wild boar through contact without negative experiences. Conversely, negative attitudes were concerned about city fouling, safety or health, accepted lethal management measures, and were more frequent in older citizens with rural background, lower education, low contact with wild boar or sensitized through negative experiences. We document for the first time the sensitization and reciprocal habituation of humans to wild boar in urban areas. The identification of the drivers of citizen attitudes towards urban wildlife should be useful to design socially-accepted management measures.

Co-infection patterns in the ectoparasitic community affecting the Iberian ibex Capra pyrenaica

BACKGROUND

Sarcoptic mange is one of the main parasitic diseases affecting the Iberian ibex Capra pyrenaica. Scabietic animals suffer a decline in body condition and reproductive fitness and in severe cases may die. Although several previous studies of the pathology of this disease and the physiological changes it produces in ibex have been carried out in recent years, our knowledge of the relationship between Sarcoptes scabiei and other ectoparasites of this host is still limited.

METHODS

We analysed 430 Iberian ibex skin samples. Ectoparasites were removed, counted and identified. Mite (S. scabiei) numbers were obtained after digesting the skin samples in a 5% KOH solution. We modelled mite numbers in terms of host sex and age, site, year, season and the presence of other ectoparasites such as ticks and lice using generalized linear mixed models (GLMMs) and ectoparasite co-occurrence patterns using two different models: the probabilistic model species co-occurrence and the generalized linear latent variable model (GLLVM).

RESULTS

The ectoparasite community was mainly composed of S. scabiei, six ticks (Haemaphysalis sulcata, Haemaphysalis punctata, Rhipicephalus bursa, Rhipicephalus turanicus, Dermacentor marginatus and Ixodes ricinus) and two lice (Bovicola crassipes and Linognathus stenopsis). Adult male ibex harboured more mites than females. Mite numbers varied greatly spatially and seasonally and increased with the presence of other parasites. Some positive co-occurrence relationships between pairs of different ectoparasites were observed, particularly between ticks. The presence of S. scabiei negatively affected lice and H. sulcata numbers.

CONCLUSIONS

Sarcoptic mange has spread above all in ibex populations in and around the Mediterranean Basin, where it is now found in almost a third of its host's range. Mite numbers varied seasonally and spatially and were higher in male hosts. The presence of S. scabiei had a negative effect on lice numbers but favoured the presence of ticks.

Assessing mammal trapping standards in wild boar drop-net capture

Applying contemporary trapping standards when managing wildlife should no longer be an option, but a duty. Increasing wild boar populations originate a growing number of conflicts and hunting is the only cost-effective management option in most cases. However, new scenarios where hunting is unfeasible emerge and trapping necessities cope with lacking regulatory frameworks and technical guidelines. In this research, we evaluated drop nets, a capture method not considered by the international trapping standards, to capture Eurasian wild boar (Sus scrofa), a wildlife species not included in the list of mammal species under the scope of the Agreement on International Humane Trapping Standards (AIHTS). Less than 20% of the captured wild boars presented moderate or severe injuries attributable to the capture method, hence fulfilling the acceptance thresholds of the outdated AIHTS. Based on the new standards thresholds of acceptance, the humaneness of drop-nets in our study ranged 66-78%, under the 85% required. The capture success and selectivity were 100%, as ensured by operator-driven triggering, which should be considered the main strengths of this method, together with the minimization of animal suffering owing the short duration of the stressful situation. Additionally, in spite of the socially adverse environment, with people contrary to wild boar removal, no disturbances against the capture system or operations occurred. This is the first assessment of a drop-net capture method according to internationally accepted mammal trapping standards, with unconclusive results. However, there is a need for adapted procedures and thresholds of acceptance aimed at not-mechanical traps in general, and specifically at drop-nets. Compared to other live-capture methods, drop-nets minimize the duration of the stressful situation -at the expense of a strong adrenergic acute response-, maximize the probabilities of capturing entire sounders of prosocial species, which may be also considered as more humane, and has the ability to coordinate higher values of capture success, absolute selectivity and adaptability to difficult environments.

Genetic population structure defines wild boar as an urban exploiter species in Barcelona, Spain

Urban wildlife ecology is gaining relevance as metropolitan areas grow throughout the world, reducing natural habitats and creating new ecological niches. However, knowledge is still scarce about the colonisation processes of such urban niches, the establishment of new communities, populations and/or species, and the related changes in behaviour and life histories of urban wildlife. Wild boar (Sus scrofa) has successfully colonised urban niches throughout Europe. The aim of this study is to unveil the processes driving the establishment and maintenance of an urban wild boar population by analysing its genetic structure. A set of 19 microsatellite loci was used to test whether urban wild boars in Barcelona, Spain, are an isolated population or if gene flow prevents genetic differentiation between rural and urban wild boars. This knowledge will contribute to the understanding of the effects of synurbisation and the associated management measures on the genetic change of large mammals in urban ecosystems. Despite the unidirectional gene flow from rural to urban areas, the urban wild boars in Barcelona form an island population genotypically differentiated from the surrounding rural ones. The comparison with previous genetic studies of urban wild boar populations suggests that forest patches act as suitable islands for wild boar genetic differentiation. Previous results and the genetic structure of the urban wild boar population in Barcelona classify wild boar as an urban exploiter species. These wild boar peri-urban island populations are responsible for conflict with humans and thus should be managed by reducing the attractiveness of urban areas. The management of peri-urban wild boar populations should aim at reducing migration into urban areas and preventing phenotypic changes (either genetic or plastic) causing habituation of wild boars to humans and urban environments.

Zoonotic Campylobacter spp. and Salmonella spp. carried by wild boars in a metropolitan area: occurrence, antimicrobial susceptibility and public health relevance

Campylobacter spp. and Salmonella spp. are the most reported zoonotic agents in Europe. They can be transmitted from wildlife to humans, and wild boars (Sus scrofa) can harbour them. In the Metropolitan Area of Barcelona (MAB, NE Spain) wild boars are found in urbanized areas. To assess the potential public health risk of this increasing wild boar population, we collected stool samples from 130 wild boars from the MAB (June 2015 - February 2016), to determine the Campylobacter and Salmonella occurrence and the antimicrobial susceptibility of the isolates. We also investigated the genetic diversity and virulence potential of Campylobacter. Campylobacter prevalence in wild boars was 61%. Forty six percent of wild boars carried Campylobacter lanienae, 16% carried Campylobacter coli, and 1% carried Campylobacter hyointestinalis; 4% carried both C. lanienae and C. coli, and 1% carried both C. lanienae and C. hyointestinalis. This is the first report of C. hyointestinalis in wildlife in Spain. Using pulse-field gel electrophoresis and multilocus sequence typing, we observed a high genetic diversity of Campylobacter and identified new sequence types. Thirty-three percent of C. coli and 14% of C. lanienae isolates showed a high virulence potential. All of the Campylobacter isolates analysed were resistant to at least one antimicrobial agent. Multidrug resistance was only detected in C. coli (67%). Salmonella enterica subsp. enterica was detected in four wild boars (3%) and included a S. Enteritidis serovar (1/4 wild boars) and a multidrug-resistant (ASSuT) monophasic S. Typhimurium serovar (1/4 wild boars) which is associated with human infections and pig meat in Europe. The characteristics of some of the Campylobacter and Salmonella isolates recovered suggest an anthropogenic origin. Wild boars are a reservoir of Campylobacter and have the potential to spread antimicrobial resistant Campylobacter and Salmonella in urbanized areas in the MAB.

Ticks on wild boar in the metropolitan area of Barcelona (Spain) are infected with spotted fever group rickettsiae

Tick-borne pathogens (TBPs) constitute an emerging public health concern favoured by multidimensional global changes. Amongst these, increase and spread of wild boar (Sus scrofa) populations are of special concern since this species can act as a reservoir of zoonotic pathogens and promote tick abundance. Thus, we aimed to make a first assessment of the risk by TBPs resulting from wild boar and ticks in the vicinity of a highly populated area. Between 2014 and 2016, we collected spleen samples and 2256 ticks from 261 wild boars (out of 438 inspected) in the metropolitan area of Barcelona (MAB; northeast Spain). We morphologically identified four tick species: Hyalomma lusitanicum (infestation prevalence: 33.6%), Dermacentor marginatus (26.9%), Rhipicephalus sanguineus sensu lato (18.9%) and R. bursa (0.2%). Ticks were pooled according to species and individual host. A total of 180 tick pools and 167 spleen samples were screened by real-time PCR and/or reverse line blot hybridization assay for Ehrlichia sp., Anaplasma sp., Babesia sp., Rickettsia sp., Borrelia burgdorferi sensu lato and Coxiella burnetii. Seventy-two out of the 180 tick pools were positive to Rickettsia spp. (minimum prevalence of 8.7%), including Rickettsia massiliae, R. slovaca and R. raoultii. We did not detect Rickettsia spp. in wild boar spleens nor other TBPs in ticks or wild boars. Since the ticks identified can bite humans, and the recorded spotted fever group (SFG) rickettsiae are zoonotic pathogens, there is a risk of SFG rickettsiae transmission for MAB inhabitants. Our results suggest a broader distribution of H. lusitanicum, competent vector for the Crimean-Congo haemorrhagic fever virus than previously known. Wild boar is not a Rickettsia spp. reservoir according to the spleen negative results. However, its abundance could favour tick life cycle and abundance, and its proximity to humans could promote the infection risk by Rickettsia spp.

Wild boar in the city: Phenotypic responses to urbanisation

Urbanisation is a global human-induced environmental change and one of the most important threats to biodiversity. To survive in human-modified environments, wildlife must adjust to the challenging selection pressures of urban areas through behaviour, morphology, physiology and/or genetic changes. Here we explore the effect of urbanisation in a large, highly adaptable and generalist urban adapter species, the wild boar (Sus scrofa, Linnaeus 1758). From 2005 to 2018, we gathered wild boar data and samples from three areas in NE Spain: one urban (Barcelona municipality, n = 445), and two non-urban (Serra de Collserola Natural Park, n = 183, and Sant Llorenç del Munt i Serra de l'Obac Natural Park, n = 54). We investigated whether urbanisation influenced wild boar body size, body mass, body condition, and the concentration of serum metabolites, considering also the effect of age, sex and use of anthropogenic food resources. Wild boars from the urban area had larger body size, higher body mass, better body condition, and a higher triglyceride and lower creatinine serum concentrations than non-urban wild boars. In addition, urban wild boars consumed food from anthropogenic origin more frequently, which suggests that differences in their diet probably induced the biometric and the metabolic changes observed. These responses are probably adaptive and suggest that wild boars are thriving in the urban environment. Our results show that urbanisation can change the morphological and physiological traits of a large mammal urban adapter, which may have consequences in the ecology and response to urban selection pressures by the species. The phenotypic plasticity shown by wild boars provides both further and new evidence on the mechanisms that allow urban adapter species of greater size to respond to urbanisation, which is expected to continue growing globally over the coming decades.

Detection of Beta-Lactam-Resistant Escherichia coli and Toxigenic Clostridioides difficile Strains in Wild Boars Foraging in an Anthropization Gradient

Disease transmission among wild boars, domestic animals and humans is a public health concern, especially in areas with high wild boar densities. In this study, fecal samples of wild boars (n = 200) from different locations of the Metropolitan Area of Barcelona were analyzed by PCR to explore the frequency of β-lactamases and extended cephalosporin and carbapenem resistance genes (ESBLs) in Escherichia coli strains and the presence of toxigenic Clostridioides difficile. The prevalence of genes conferring resistance to β-lactam antimicrobials was 8.0% (16/200): bla_CMY-2 (3.0%), bla_TEM-1b (2.5%), bla_CTX-M-14 (1.0%), bla_SHV-28 (1.0%), bla_CTX-M-15 (0.5%) and bla_CMY-1 (0.5%). Clostridioides difficile TcdA+ was detected in two wild boars (1.0%), which is the first report of this pathogen in wild boars in Spain. Moreover, the wild boars foraging in urban and peri-urban locations were more exposed to AMRB sources than the wild boars dwelling in natural environments. In conclusion, the detection of E. coli carrying ESBL/AmpC genes and toxigenic C. difficile in wild boars foraging in urban areas reinforces the value of this game species as a sentinel of environmental AMRB sources. In addition, these wild boars can be a public and environmental health concern by disseminating AMRB and other zoonotic agents. Although this study provides the first hints of the potential anthropogenic sources of AMR, further efforts should be conducted to identify and control them.

Endemic occurrence of Fasciola hepatica in an alpine ecosystem, Pyrenees, Northeastern Spain

Fasciola hepatica is a liver parasite of ruminants whose distribution is determined by its intermediate host, the freshwater snail Galba truncatula. In Europe, F. hepatica is mostly associated with lowlands. Infection from sympatric domestic reservoirs is rarely reported in wild mountain ungulates. This study explores F. hepatica in a multi-host system in a European alpine area. Serum samples (n = 1,209) from Pyrenean chamois (Rupicapra p. pyrenaica), European mouflon (Ovis aries musimon), domestic sheep (Ovis aries) and domestic cattle (Bos taurus) were collected in the National Game Reserve of Freser-Setcases (NGRFS) in Catalonia, Northeastern Spain, from 2008 to 2019, and tested for antibodies against F. hepatica. During the same period, the livers of 214 chamois hunted in the NGRFS were inspected for F. hepatica and associated pathological changes. Finally, 907 freshwater snails were collected in summer 2016 between 1559 and 2,224 metres above sea level (asl) in the NGRFS, and F. hepatica DNA sought by PCR. Antibodies against F. hepatica were detected in all four species, with a higher prevalence in cattle and sheep than in chamois. Fasciola hepatica and hepatic lesions were concurrently observed in 13/214 of the chamois livers inspected (6.1%, CI95 2.9%-9.3%). Fasciola hepatica DNA was detected in one out of the 907 snails (0.1%, Cl95 0.1% - 0.3%; Ct value 33.3) and collected at 2054 m asl. Fasciola hepatica was consistently detected in a high mountain multi-host system, suggesting that its life cycle is completed and that it occurs endemically at the highest elevation reported in Europe. Transhumant livestock are the likely source in this alpine ecosystem, which according to rare occurrence of F. hepatica DNA in G. truncatula is still a suboptimal habitat for F. hepatica life cycle. Studying parasites at their highest distribution range can be useful to monitor climate change in seasonal mountain environments.

Accumulation of diastereomers of anticoagulant rodenticides in wild boar from suburban areas: Implications for human consumers

We studied the prevalence of anticoagulant rodenticides (ARs) in liver and muscle tissues of wild boar captured in the urban area of Barcelona, the suburban area of Collserola Natural Park and the rural area of Santa Quiteria, next to Cabañeros National Park, in Spain. The objective was to assess the influence of both urbanisation and wild boar (Sus scrofa) trophic opportunism on the accumulation of these compounds. We have also evaluated the risk for human consumers of this game meat. Wild boars from Barcelona city showed the highest prevalence of ARs detection (60.8%), followed by the adjoining suburban area of Collserola N.P. (40%) and the rural distant area of Santa Quiteria (7.7%). Liver bioaccumulated ARs (45.2%) more frequently than muscle (11.9%). A significant proportion (13.7%) of wild boar captured in Barcelona city exceeded 200 ng/g of total ARs in liver, a threshold for adverse effects on blood clotting. For difenacoum, there was a predominance of cis isomer, while for brodifacoum and bromadiolone cis and trans isomers appeared in a similar proportion. According to the scarce available information on ARs toxicity in humans, the risk of acute poisoning from game meat consumption seems to be low. However, repeated exposure through liver consumption should be considered in further risk assessments because of the high concentration detected in some samples (up to 0.68 mg/kg).

Assessing methods to live-capture wild boars (Sus scrofa) in urban and peri-urban environments

BACKGROUND

Wild boar (Sus scrofa) populations are increasing worldwide and invading urban areas. Live-capture can improve the management of this challenge, maximising efficiency, allowing scientific studies and potentially improving animal welfare. This study assesses teleanaesthesia, drop-net, corral trap and cage trap to live-capture wild boar in urban and peri-urban areas, evaluating efficiency and animal stress through haematology and serum biochemistry.

METHODS

From 2012 to 2018, 655 wild boars were captured in 279 operations (drop-net=17, teleanaesthesia=186, cage trap=66 and corral trap=10) in the urban and peri-urban areas of Barcelona (Spain). Haematological and serum biochemical variables were determined in 145 wild boars (42 drop-netted, 41 teleanaesthetised, 38 cage-trapped and 24 corral-trapped).

RESULTS

Performance (wild boars captured per operation) was highest for drop-net, followed by corral and cage traps, and finally teleanaesthesia. The three physical capture methods were more stressful than teleanaesthesia, causing a more intense physiological reaction, muscular damage, renal function impairment and homeostasis adaption. Stress response was predominantly adrenergic for drop-net and cortisol-induced for cage and corral traps.

CONCLUSION

Teleanaesthesia is the choice in reactive urban situations thanks to its adaptability; drop-net effectively targets wild boars in peri-urban environments; cage and corral traps are useful as long-term methods in specific areas.

Urban Wild Boars and Risk for Zoonotic Streptococcus suis, Spain

Urban wild boars (Sus scrofa) from Barcelona, Spain, harbor great diversity of Streptococcus suis strains, including strains with the cps2 gene and with the same molecular profile as local human cases. The increasing trend of potential effective contacts for S. suis transmission is of public health concern.

Genetically similar hepatitis E virus strains infect both humans and wild boars in the Barcelona area, Spain, and Sweden

Hepatitis E virus (HEV) is a hepatotropic virus, endemic in Europe where it infects humans and animals, with domestic pigs and wild boars as main reservoirs. The number of HEV-infected cases with unknown source of infection increases in Europe. There are human HEV strains genetically similar to viruses from domestic pigs, and zoonotic transmission via consumption of uncooked pork meat has been shown. Due to continuous growth of the wild boar populations in Europe, another route may be through direct or indirect contacts with wild boars. In the Collserola Natural Park near Barcelona, Spain, the wild boars have spread into Barcelona city. In Sweden, they are entering into farmlands and villages. To investigate the prevalence of HEV and the risk for zoonotic transmissions, the presence of antibodies against HEV and HEV RNA were analysed in serum and faecal samples from 398 wild boars, 264 from Spain and 134 from Sweden and in sera from 48 Swedish patients with HEV infection without known source of infection. Anti-HEV was more commonly found in Spanish wild boars (59% vs. 8%; p < 0.0001) while HEV RNA had similar prevalence (20% in Spanish vs. 15% in Swedish wild boars). Seven Swedish and three Spanish wild boars were infected with subtype 3f, and nine Spanish with subtype 3c/i. There were three clades in the phylogenetic tree formed by strains from wild boars and domestic pigs; another four clades were formed by strains from humans and wild boars. One strain from a Spanish wild boar was similar to strains from chronically infected humans. The high prevalence of HEV infections among wild boars and the similarity between wild boar HEV strains and those from humans and domestic pigs indicate that zoonotic transmission from wild boar may be more common than previously anticipated, which may develop into public health concern.

Porcine circovirus 3 is highly prevalent in serum and tissues and may persistently infect wild boar (Sus scrofa scrofa)

Porcine circovirus 3 (PCV-3) prevalence has been minimally investigated in wild boar; dynamics of infection and viral tissue distribution are currently unknown. In this study, serum samples from 518 wild boar (from years 2004 to 2018) were used to study frequency of infection. Also, serum samples from 19 boar captured and recaptured at least two times for a period of time from 1 month to 1 year were collected to determine PCV-3 infection dynamics. Finally, to elucidate PCV-3 DNA organic distribution, sera, different tissues and faeces were obtained from 35 additional wild boar. PCV-3 DNA was extracted and amplified with a conventional PCR. For the PCV-3 PCR-positive sera from the longitudinally sampled and different tissue types, a quantitative PCR was performed. Genome sequence was obtained from a number of PCV-3 PCR-positive samples from different years, different time-points of infection and tissues. Obtained results confirmed the susceptibility of wild boar to the virus, showing high frequency of PCV-3 detection (221 out of 518, 42.66%) and demonstrating circulation at least since 2004. Compiled data indicate the possibility of long-term infections, since 5 out of 10 PCV-3 PCR-positive boars longitudinally sampled showed positivity in samplings separated for more than 5 months. All tested tissue types' harboured PCV-3 genome, with the highest percentage of PCR positivity in submandibular lymph node, tonsil, lung, liver, spleen and kidney. The amount of DNA in all tested PCV-3 PCR-positive samples was moderate to low. All partial and complete PCV-3 sequences obtained from wild boar displayed high nucleotide identity, higher than 98%. In conclusion, this study further confirms that wild boar is susceptible to PCV-3 infection, showing high frequency of detection in this animal species. Furthermore, PCV-3 can be found in different tissues of wild boar and is apparently able to cause persistent infection.

Stochastic assessment of management strategies for a Mediterranean peri-urban wild boar population

Wild boar (Sus scrofa) population spread into urban and periurban areas has exacerbated conflicts with humans. There is a need for planned wild boar management strategies, and Population viability analysis (PVA) combined with perturbation analyses allow the assessment of the management effort of control methods. Our study aims to develop stochastic predictive models of the increasing wild boar population of the 80 km² peri-urban Mediterranean area of Collserola Natural Park (CNP), located near Barcelona, Spain, as well as assessing specific management measures (including reduced food availability, selective harvest, and reduction in fertility). Population parameters were estimated from previously published census and hunting data provided by the CNP and the local hunting administration. The results revealed that under the current conditions the CNP wild boar population will continue to increase. The most efficient strategy to reduce wild boar abundance was a combination of reducing supplementary anthropogenic food resources and selective removal of juvenile (<1 year) and yearling (1–2 years) wild boar. These strategies will probably be also the most efficient ones in other oversupplemented increasing wild boar populations in similar situations, although specific studies will be needed to fine-tune the best management option for each context. PVA allows the prediction of future population trends and the assessment of the efficacy and efficiency of potential management strategies before implementing management measures.

Serological survey in wild boar (Sus scrofa) in Switzerland and other European countries: Sarcoptes scabiei may be more widely distributed than previously thought

Background

Sarcoptic mange has recently emerged in wild boar in Switzerland, raising the question of the origin of the infection. The main aim of this study was to assess the extent of exposure of the wild boar populations to Sarcoptes scabiei in Switzerland, prior to and after the detection of mange cases, to determine whether the mite has been recently introduced into the populations concerned. We performed a serological survey using a commercially available ELISA and 1056 archived blood samples of free-ranging wild boar from Switzerland. To facilitate the interpretation of the obtained data, we additionally estimated seroprevalence in wild boar populations of four other European countries (1060 samples), both from areas with confirmed clinical cases of mange and from areas without reported cases in wild boar. Lastly, we revised the evaluation of the commercial ELISA when used with wild boar sera.

Results

Seropositive reactions were observed for samples from all five countries and from 15 of the 16 study areas. The obtained apparent seroprevalences ranged from 0.0% (0/82; 95% confidence interval [CI]: 0.0–4.4) to 17.4% (8/46; 95% CI: 7.8–31.4). Wild boar from study areas with known clinical cases and those ≤60 kg were four times more likely to be seropositive than wild boar from areas without reported cases and > 60 kg, respectively. Optical density values did not differ between the two types of study areas among seropositive samples but were significantly lower among seronegative samples from areas without than from areas with clinical cases. No difference was observed between the two sampling periods in Switzerland. The revised ELISA specificity was 96.8% (984/1017; 95% CI: 95.5–97.7) when wild boar from areas without history of mange were considered truly negative.

Conclusions

Seropositivity to S. scabiei is more frequent and occurs over a larger geographic range than expected. Data suggest that the parasite is endemic within the wild boar populations of Switzerland and other European countries but that its presence is not necessarily associated with disease occurrence. Extrinsic factors which trigger disease emergence in infected populations remain to be investigated. The applied ELISA represents a promising tool for future studies.

Electronic supplementary material

The online version of this article (10.1186/s12917-018-1430-3) contains supplementary material, which is available to authorized users.

On the possible role of ticks in the eco-epidemiology of Coxiella burnetii in a Mediterranean ecosystem

Ruminant livestock is the main reservoir of Coxiella burnetii (Cb), but little is known about the role of wildlife and ticks in its epidemiology. The Iberian ibex (Capra pyrenaica, Schinz 1838) population of "Ports de Tortosa i Beseit" (NE Spain) suffers intense tick infestations and low reproduction rates. This study aims to (1) assess the relationship between infection in ibexes (detection of serum antibodies and/or of Cb DNA in tissues) and Cb DNA presence in ticks hosted by the same ibexes; and (2) identify Cb associated risk factors. Between 2011 and 2015, serum (n = 130), spleen (n = 72), lymph node (n = 89) and tick (n = 669) samples from 134 hunter-harvested ibexes were collected. Antibody detection was performed by ELISA and Cb DNA presence was assessed by PCR. Potential risk factors were assessed with regression tree models. Although 30% of the ibexes (39/130; 95%CI, [10%-29.8%]) had antibodies, Cb DNA was detected in only 9.8% of the ibexes (11/112; 95%CI [7.6%-27.25%]). The prevalence of Cb-carrier ticks averaged 10% and exceeded 20% for the genus Haemaphysalis. However, lacking correlation between infection in ibexes and their ticks does not support tick-to-ibex transmission or vice versa. Tree modelling points to host, population and environmental factors as drivers of Cb infection in ticks and suggests connections with the domestic cycle. The percentage of Cb-carrier ticks detected is noteworthy. Along with heavy tick infestations, it suggests vector potential for these tick species, especially for the genera Rhipicephalus and Haemaphysalis. Since vector competence has not been assessed in these tick species, a classic vector role cannot be proposed nor discarded, but promoter factors of vector capacity occur. In addition, the risk of tick-borne infection through tick excreta should not be neglected. While the airborne route is the preeminent route for Cb infection, ticks' contribution to Cb epidemiology deserves further attention.

Urban wild boars prefer fragmented areas with food resources near natural corridors

Wild boar populations are expanding throughout the world and intruding into periurban and urban areas. In the last years, wild boar has colonized several European cities, including our study area, the city of Barcelona. It is required to identify the main factors driving wild boar into urban areas prior to establish management measures. We built Boosted Regression Trees (BRT) using 3148 wild boar presences registered in the urban area of Barcelona from 2010 to 2014 to identify the variables correlated with these presences. The variables analysed included proxies for distance to source population, urban food resources, climate and urban habitat structure. Wild boars enter the urban area from close natural habitat using corridors such as streams, preferably in fragmented urban environment, looking for food such as urban green areas or dry pet food from cat colonies. Wild boar presence is higher in spring possibly due to the births of piglets and the dispersion of yearlings during that season, and also when natural resources in the Mediterranean habitat fail to satisfy the nutritional requirements of the wild boar population during the summer season. Management measures derived from this study are currently being applied in the city of Barcelona, including vegetation clearings in the wild boar entrance areas and an awareness campaign aimed at reducing the anthropogenic food availability for wild boars. The methodology used can be applied to other cities with wild boar or even other wildlife species issues. The comparison between the factors attracting wild boars into different urban areas would be helpful to understand the global phenomenon.

Coprological tests underestimate Macracanthorhynchus hirudinaceus burden in wild boar

The present study evaluated the limitations of the coprological sedimentation test to assess Macracanthorhynchus hirudinaceus infestation in 59 wild boars (Sus scrofa) from central Spain. The coprological sedimentation test appeared to be a poor predictor of both prevalence of infestation and the real parasite burden due to the high number of false negative results (prevalence was reduced from 61 to 16 %). Because of the potential increased risk of this zoonosis, it is suggested that alternative techniques be used in wildlife surveillance programmes.