Antimicrobial resistance is a global One Health concern, and vancomycin-resistant Enterococcus (VRE) remains one of the clinically important resistant bacterial groups. Although VRE has been extensively studied in clinical and livestock settings, it has been investigated far less often in free-ranging wild animals. This scoping review maps the published evidence on VRE in wild animals, with emphasis on reported prevalence, host and environmental correlates, anthropogenic exposures, and laboratory detection methods rather than quantifying pooled effect sizes. A structured search of PubMed, ScienceDirect, Scopus, Web of Science, and Google Scholar was conducted from database inception to the final search stage used for this review, with only peer-reviewed English-language primary studies contributing empirical wildlife VRE data included in the synthesis. Eligibility was guided by the Population-Concept-Context framework, and the mapped evidence included mammals plus one reptile study retained in the review scope. Twenty-five studies met the inclusion criteria. Most were conducted in Europe, with substantially fewer studies from Africa and South America, indicating major geographical gaps. Reported prevalence ranged from 1.08% in feral pigs in Brazil to 100% in wild rabbits in Spain, although several striking estimates were based on very small samples and should be interpreted cautiously. Culture-based methods were most frequently used, whereas PCR-based approaches were particularly useful for confirming resistance genes. Overall, the evidence suggests that wild animals can act as reservoirs or sentinels of VRE exposure in anthropogenically influenced environments. Standardized surveillance, clearer reporting, and broader One Health monitoring that explicitly includes wildlife are needed.

Staphylococcus aureus is a commonly found bacteria on the skin and mucous membranes of humans and animals. It can act as an opportunistic pathogen causing multiple infections of diverse severity. Moreover, S. aureus can acquire resistance to multiple antibiotics, with methicillin-resistant S. aureus (MRSA) being a significant global health concern. European wild rabbit (Oryctolagus cuniculus) is an important species in Iberian ecosystems and can serve as reservoirs for zoonotic bacteria. In this study, 472 nasal samples from wild rabbits in Spain and Portugal were analyzed to determine the prevalence, antimicrobial resistance, and molecular characteristics of S. aureus. Overall, S. aureus was detected in 13.6% of animals, with higher prevalence in animals of Spain (27.4%) than in those of Portugal (6.2%). MRSA was found in 51 samples (10.8%), predominantly carrying the mecC-agrIII-SCCmecXI genes associated with CC130, and three isolates carried mecA-agrI-SCCmecV and belonged to CC398. Resistance to penicillin (92.1%), cefoxitin (79.6%), ciprofloxacin (7.9%), tetracycline (5.7%), erythromycin (2.3%) and gentamicin (1.1%) was observed. A marked intra-host diversity was detected and different S. aureus isolates were observed in the same sample in 35.4% of the positive rabbits. Virulence genes lukED and etd2 were frequent, whereas the scn human-adaptation marker (IEC system) was present in 33.0% of the eighty-eight non repetitive S. aureus isolates. These results suggest that Iberian wild rabbits may constitute a relevant reservoir of MRSA-mecC-CC130, highlighting their potential role in One-Health dynamics, warranting continued wildlife surveillance.

Veterinary spending patterns for pet rabbits in Spain

Background: European wild rabbits (Oryctolagus cuniculus) are closely connected to the natural environment and might be a potential source of pathogenic bacteria and/or antimicrobial-resistant bacteria. The objective was to identify the bacterial community (species and genera) that colonizes the nasal cavities of European wild rabbits as well as to study the antimicrobial resistance (AMR) phenotypes of bacteria of public health interest. Methods: A total of 147 nasal swabs individually collected from wild rabbits in Spain and Portugal (between 2022 and 2024) were studied. Samples were inoculated in different culture media, and isolates were identified by MALDI-TOF. The AMR phenotypes of staphylococci, mammaliicocci, enterococci and Enterobacterales were evaluated by the disk-diffusion method. Results: Overall, 557 non-repetitive isolates were obtained (1 isolate per species and AMR phenotype of each animal). A wide diversity of genera (n = 40) and species (n = 90) was found. Staphylococcus (21.2%), Mammaliicoccus (11.7%), Enterococcus (23.3%), Enterobacter (9.2%), Citrobacter (4.5%) and Escherichia (5.9%) were the most detected genera. Most animals presented more than one genera (78.9%), and in 15.7% of them, at least five genera were identified. Susceptibility to all antimicrobials tested was found in 37.2%, 38.5% and 51.6% of staphylococci/mammaliicocci, enterococci and Escherichia coli isolates; moreover, multidrug resistance was detected in 10.4%, 14.6% and 9.6% of these groups of bacteria. Moreover, important species of pathogenic bacteria were found, such as Yersinia enterolocolitica (0.5%) and Bordetella bronchiseptica (0.2%), among others. Conclusions: A high bacterial diversity was detected in the nasal cavities of European wild rabbits from the Iberian Peninsula, including pathogenic species and/or resistant strains of public health interest.

Household waste landfills represent a huge source of trophic resources for opportunistic and versatile wildlife species. Among them, the red kite (Milvus milvus) is one of the most endangered in Europe. Several studies have pointed out the importance of landfills as a source of food for this species during the wintering season, but the information on the frequency, seasonal and daily patterns of use, and age of red kites that exploit this food source is still insufficient to understand their actual role in conservation. In this study, we evaluated the patterns of use of household waste by overwintering red kites in southeastern Madrid, central Spain. The results showed the constant presence of relatively low numbers (<30 on average) and a reduced hourly inflow and outflow of red kites throughout the day and during the whole winter period in the studied landfill. A higher proportion of juveniles was found in the landfill than in the overall wintering population. Pellet analysis clearly shows that the diet of red kites is dominated by the wild rabbit (Oryctolagus cuniculus), which is quantitatively very relevant compared to household waste obtained from the landfill. This suggests a relatively low quantitative importance of landfills as foraging grounds for the increasing population of wintering red kites in the study area. Instead, the high regional density of wild rabbits attracts large numbers of red kites that can eventually use landfills as a non-optimal last-resort foraging option, owing to the predictability of household waste, especially for juveniles. The continuous presence of red kites in landfills likely influences an uninformed positive perception about their relevance to the conservation of the wintering population, despite risks there faced, such as collision, electrocution, and intoxication. Future research is needed to assess in depth the influence of wild rabbits in Spain on the habitat use and global population dynamics of red kites.

Research on antimicrobial resistance (AMR) in pet rabbits is very scarce. The aim of this study was to provide an overview of the current state of AMR in rabbits attended to in veterinary clinics distributed in Spain. Records of 3596 microbiological results of clinical cases submitted from 2010 to 2021 were analyzed. Staphylococcus spp. (15.8%), Pseudomonas spp. (12.7%), Pasteurella spp. (10%), Bordetella spp. (9.6%) and Streptococcus spp. (6.8%) were the most frequently diagnosed agents. Enterobacteriaceae, principally Escherichia coli, Klebsiella pneumoniae and Enterobacter cloacae, accounted for about 18% of the cases and showed the highest proportion of multi-drug resistance (MDR) isolates, with 48%, 57.5% and 36% of MDR, respectively. Regarding the antimicrobial susceptibility testing for a number of antimicrobial categories/families, the largest proportion of isolates showing resistance to a median of five antimicrobial categories was observed in P. aeruginosa, Stenotrophomonas maltophilia and Burkolderia spp. In contrast, infections caused by Staphylococcus, Streptococcus spp. and Pasteurella multocida were highly sensitive to conventional antimicrobials authorized for veterinary use (categories D and C). The emergence of AMR major nosocomial opportunistic pathogens such as P. aeruginosa, S. maltophilia and K. pneumoniae in pet rabbits can represent a serious public health challenge. Consequently, collaboration between veterinarians and human health professionals is crucial in the fight against antimicrobial resistance, to optimize, rationalize and prudently use antimicrobial therapies in domestic animals and humans.

Enterocytozoon bieneusi and Encephalitozoon spp. are microsporidia with zoonotic potential that have been identified in humans, as well as in a large group of wild and domestic animals. Several wildlife species have been studied as reservoirs of zoonotic microsporidia in mainland Spain, including the European rabbit (Oryctolagus cuniculus). Due to a lack of data on microsporidia infection in wildlife on the Canary Islands, the aim of this work was to analyze the prevalence and identify the species of microsporidia in rabbits in Tenerife. Between 2015 and 2017, a total of 50 fecal samples were collected from rabbits in eight municipalities of Tenerife, Canary Islands, Spain. Seven of the fifty samples (14%) were amplified using nested polymerase chain reaction (PCR) targeting the partial sequence of the 16S rRNA gene, the internal transcribed spacer (ITS) region, and the partial sequence of the 5.8S rRNA gene. Sanger sequencing reveals the presence of Encephalitozoon cuniculi genotype I in two samples (4%), and undescribed microsporidia species in five samples (10%). This study constitutes the first molecular detection and genotyping of E. cuniculi in rabbits in Spain.

Cryptosporidium cuniculus is a zoonotic parasite responsible for cryptosporidiosis cases and outbreaks in both humans and rabbits. Since there are no molecular Cryptosporidium spp. infection data in rabbits (Oryctolagus cuniculus) from Spain, our aim was to gather information about this parasite in wild European rabbits from Tenerife, Canary Islands (Spain). A total of 100 faecal samples were collected from rabbits from eight municipalities of Tenerife. Microscopic analysis showed that 4.0% of the samples presented structures compatible with Cryptosporidium oocyst. A nested polymerase chain reaction (PCR) targeting 18S ribosomal RNA (rRNA) gene fragments was carried out, and sequencing confirmed the identity of C. cuniculus in one sample (1.0%). The sample was successfully subtyped using nested PCR analysis of the 60-kDa glycoprotein (gp60) gene as the subtype VbA26R3. This study confirms the presence of C. cuniculus in wild rabbits from Tenerife, providing new information on the occurrence of this zoonotic parasite. Further studies are required to better understand the epidemiology of Cryptosporidium spp. in wild rabbits in Spain and their possible public health repercussions.

In recent decades, cases of autochthonous hepatitis E (HE) have sharply increased in European countries where foodborne transmission is considered the main route of HE virus (HEV) transmission. Although rabbits are considered the main reservoir of the zoonotic HEV-3ra subtype, information on the role of wild lagomorphs in the epidemiology of HEV remains scarce. The aim of this study therefore was to assess the circulation of HEV in European wild rabbits (Oryctolagus cuniculus) and Iberian hares (Lepus granatensis), the most important lagomorph species in Spanish Mediterranean ecosystems. Liver samples from 372 wild rabbits and 78 Iberian hares were analysed using a broad-spectrum RT-PCR that detects HEV genotypes 1-8. None of the 450 lagomorphs tested were positive for HEV infection. To the best of our knowledge, this is the first study to assess HEV circulation in wild rabbits in Spain and the first to evaluate HEV infection in Iberian hares. Our results indicate absence of HEV circulation in wild rabbits and Iberian hares in southern Spain during the study period, which suggests that the risk of transmission of HEV from wild lagomorphs to other species, including humans, is low.

Simple SummaryMyxomatosis has affected the European domestic rabbit in Spain since the end of 1953; and rabbit haemorrhagic disease (RHD) since mid-1988. In this study, we describe the occurrence of myxomatosis; and RHD; on commercial rabbitries visited in Spain; between 1988 and 2018. Annual occurrence of myxomatosis decreased over 30 years. Cases of myxomatosis were detected most frequently between August and March; more cases occurring in September and fewer in June. Two important RHD epidemics occurred; the first in 1988–1989 due to classic RHD virus (RHDV), and the second from 2011 to 2013 due to new calicivirus (RHDVb/RHDV2). Monthly occurrence of RHD in 2011–2018 was higher from April to August. Despite seasonal variations of these diseases; we recommend that young breeders and adults should be protected by vaccination all year round; and on-farm hygiene measures implementedIn this retrospective study, we describe the relative occurrence of clinical myxomatosis, and rabbit haemorrhagic disease (RHD), on 1714 commercial farms visited in Spain, between 1988 and 2018. We determined the annual prevalence based on 817 visits to 394 farms affected by myxomatosis. Myxomatosis was more prevalent from August to March, being lowest in June (3%) and highest in September (8.9%). With regard to RHD, we assessed 253 visits to 156 affected farms. We analyzed mean annual and monthly incidence. Two important RHD epidemics occurred; the first in 1988–1989 due to RHDV GI.1 (also known as RHDV), and the second from 2011 to 2013 due to RHDV GI.2 (RHDV2 or RHDVb). These epidemics occurred at times when effective vaccination had not been carried out. Relative monthly incidence in 2011–2018 was higher from April to August (p < 0.001). The results we obtained from 1404 necropsies on 102 farms did not clearly relate serosanguinous nasal discharge in rabbits with disease caused by GI.2 infection. We also assessed vaccination schedules used on 200 doe farms visited from the end of 2014 to 2018; 95.5% vaccinated against myxomatosis and 97.5% against RHD. Both diseases remain prevalent; however, effective vaccination has produced a steady decline in myxomatosis and RHDV GI.1 and GI.2 on-farm detection. The maintenance of high hygienic standards will be needed to continue and improve this control. However, further studies are required to investigate the causes of sustained virus presence and vaccine breaks.

Apparent competition is an indirect interaction that can strongly influence ecosystem functioning, altering species populations within the same trophic level. As a new resource, an introduced species can generate strong apparent competition in invaded communities, and even stronger if it becomes the primary resource for consumers. We explore how the European hare (Lepus europaeus), an introduced species in Patagonia, could be generating these stronger effects since many native predators shifted their diets towards them. We constructed and compared two food webs, one in which this primary prey role is played by a native species (the European rabbit, Oryctolagus cuniculus, in Spain) and another in which it is played by an introduced one (the European hare, in Patagonia), to explore their effects in the generation of this indirect interaction. Both were the primary prey in their respective food web and caused the strongest cases of potential apparent competition in each region. Potential apparent competition generated by introduced European hares in Patagonia double that produced by the European rabbit in Spain and was several times higher than any other native prey species. This strong potential apparent competition in an invaded ecosystem highlights the threats that some exotic species may produce, even indirectly.

Rumours associated with wildlife are frequent, although they have received little attention in the scientific literature. Studying rumours is important because of their relevance not only in a broad theoretical sense but also in environmental management. The goal of this study is to explore the complexity of the relationships between humans and wildlife through a thematic analysis of rumours associated with allegedly introduced European rabbits (Oryctolagus cuniculus) that cause crop damage in Spain. For this purpose, potential rumours were identified using the Google search engine. Data analysis consisted of reading and re-reading Web-based texts to identify main themes, ideas and topics with the assistance of NVivo 10 software. The analysis identified three main themes: (1) the reviewed websites referred to allegedly introduced rabbits which differed from native rabbits; (2) differences were based on alleged observations of unnatural behaviour, physiology or physical appearance of introduced rabbits; (3) rumours were frequently used in the context of the rabbit management conflict; e.g. farmers accused hunters of releasing harmful rabbits. This study suggests that the analysis of wildlife-release rumours sheds light on the position of parties involved in conflicts associated with the (alleged) introduction of wildlife species. It stresses the importance of rumours in conservation and environmental management, and opens the door to future research.

The Iberian Peninsula is the only region in the world where the two existing subspecies of the European rabbit (Oryctolagus cuniculus) naturally occur and hybridize. In this study we explore the relative roles of historical and contemporary processes in shaping the spatial genetic structure of the rabbit across its native distribution range, and how they differently affect each subspecies and the hybrid zone. For that purpose we obtained multilocus genotypes and mitochondrial DNA data from 771 rabbits across most of the distribution range of the European rabbit in Spain. Based on the nuclear markers we observed a hierarchical genetic structure firstly comprised by two genetic groups, largely congruent with the mitochondrial lineages and subspecies distributions (O. c. algirus and O. c. cuniculus), which were subsequently subdivided into seven genetic groups. Geographic distance alone emerged as an important factor explaining genetic differentiation across the whole range, without the need to invoke for the effect for geographical barriers. Additionally, the significantly positive spatial correlation up to a distance of only 100 km supported the idea that differentiation at a local level is of greater importance when considering the species overall genetic structure. When looking at the subspecies, northern populations of O. c. cuniculus showed more spatial genetic structure and differentiation than O. c. algirus. This could be due to local geographic barriers, limited resources, soil type and/or social behavior limiting dispersal. The hybrid zone showed similar genetic structure to the southern populations but a larger introgression from the northern lineage genome. These differences have been attributed to selection against the hybrids rather than to behavioral differences between subspecies. Ultimately, the genetic structure of the rabbit in its native distribution range is the result of an ensemble of factors, from geographical and ecological, to behavioral and molecular, that hierarchically interact through time and space.

Live BW and BCS data were collected from 2,775 breeding rabbits (644 males and 2,131 females) of 34 genetic types and sorted according to their specialization (maternal, paternal, and others). Data were gathered on 66 visits to 43 commercial farms in Spain between 2009 and 2011. Mean BW was 4.72 kg (range of 2.87 to 8.13 kg, with a median BW of 4.60 kg) and mean BCS was 4.6 (range of 1.0 to 9.0, with a median BCS of 5.0). females had heavier (P < 0.05) BW than males and paternal lines of rabbits had greater (P < 0.05) BW than maternal lines and other breeds/lines not selected for meat production. Between 69.3% and 75.4% of the rabbits were deemed healthy by a veterinarian and, as expected, healthy rabbits were heavier (P < 0.05) than sick rabbits diagnosed with rhinitis, mastitis, sore hocks, and several other diseases. Among purebred, maternal lines of rabbits, Hyplus GD24, UPV A, and UPV V were heavier (P < 0.05) than hyplus GD14 and Hyla HL-D lines, and line UPV R had the greatest (P < 0.05) BW among the purebred, paternal lines. Additionally, A×H, A×V, PS19, and P×A crossbreds had greater (P < 0.05) BW than HE-C×D, HL-C×D, H×V, LP×V, and V×P crossbreds among the maternal lines, whereas HE-SL were the heaviest (P < 0.05) crossbred paternal line of rabbits. Additionally, females received greater (P < 0.05) BCS than males and BCS were greater (P < 0.05) in healthy than sick rabbits. Moreover, maternal lines had smaller (P < 0.05) BCS than either paternal lines or other lines/breeds not selected for meat production. Results also indicated a moderate relationship between BCS and BW (r = 0.32), with a 1-point change in BCS equivalent to an ~ 245-g change in BW. results from this study can be used as baseline figures for breeding rabbits in spain and are essential factors in several decisions concerning housing, feeding, reproduction, health, and welfare of breeding rabbits.

This is a report on work carried out on 4307 visits to 868 commercial farms with domestic rabbits in Spain and Portugal from January 1997 to December 2007. Of the total visits, 2237 (52%) were emergencies on 660 farms. The median size of the farms ranged between 450 does in 1997 and 750 in 2007. This retrospective study measures the clinical disease occurrence using the Monthly Risk of urgent visits (MR), i.e. the percentage of visits made as a result of each clinical disease in comparison with the total number of urgent visits made each month. The main reasons for the emergencies were mucoid enteropathy (similar to Epizootic Rabbit Enteropathy), with a MR: 25.0%, enteritis-diarrhoea (24.1%), myxomatosis, (11.1%), reproductive troubles (8.6%), respiratory diseases (7.2%) and staphylococcosis (4.2%). Fifty-four percent of the urgent visits were due to diseases of the digestive system. Mucoid enteropathy was still one of the main diseases faced by the commercial rabbit industry during the study period. No significant yearly or monthly variations were observed in the analysis of the MR. A seasonal effect was only found in respiratory diseases during the summer (MR: 11.06±0.01) and myxomatosis in autumn (MR: 14.60±0.02), in comparison with spring (MR: 7.44±0.02). It is therefore concluded that farms should be permanently protected as they might be affected by any of these diseases at any time during the year.

Extensive predator persecution caused by population crash in a game species: The case of red kites and rabbits in Spain

Animal use of habitats and patches may vary in relation to foraging profitability and predation risk (MacArthur and Pianka 1966). Around this idea, Jaksic and Soriguer (1981) made a suggestive comparison of predation upon and patterns of habitat use by European rabbit, Oryctolagus cuniculus, in Mediterranean habitats of southern Spain (the area of origin of species) and central Chile (where it had been introduced). The main conclusions of their work were: 1) predators in central Chile pass introduced rabbits by and consequently non-predated rabbits select to feed in more profitable open patches; and 2) conversely, predators in southern Spain regularly hunt native rabbits, which are forced to keep themselves close to protective vegetation avoiding open patches. To reach these conclusions, they reviewed literature on diets of predator assemblages of both places (central Chile and southern Spain) and counted rabbit pellets in different habitat patches varying in shrub cover. Jaksic and Soriguer (hereafter J&S) explained their finding that rabbits were a small component of diet of central Chile predators on their lack of behavioural adjustment (inefficiency) to hunt a recently introduced prey. Spanish data would support this idea, as rabbits and predators have co-evolved in this area and therefore latter would be efficient at hunting rabbits. On other hand, as rabbits in Chile were not preyed upon, they would behave as being predator-free, using open shrub areas where herb availability would be higher. On contrary, rabbits in Spain would select close vegetation patches where shrubs could provide them with adequate shelters (i.e. nearby shrubs would be more important than abundant food for rabbit survival). The results of J&S were so clear and presented so elegantly that in last fifteen years the Chilean and Spanish rabbit cases (i.e. reported differences in predation pressure upon rabbits in Chile and Spain and associated behavioural change in habitat use by rabbits) have been widely accepted and thus invoked by scientific community (e.g. Simonetti and Fuentes 1982, Newsome et al. 1989, Trout and Tittensor 1989, Jaksic and Fuentes 1991, Kolb 1991, Ferrer 1993). Nevertheless, fine-tuning co-evolutionary adjustment between most vertebrate predators and their prey has not been proved until now. Available data suggest that vertebrate predators are usually quite flexible and adaptable in prey selection, whether they are native predators hunting for introduced prey (e.g. Myers et al. 1994) or are introduced predators hunting for native prey (e.g. Fitzgerald 1988). On other hand, it is difficult to believe that locally abundant Spanish rabbits give up rich food of open pastures, as it has been stated that rabbits need grassy areas in Mediterranean habitats of Spain (Rogers and Myers 1979). We think it is important to reanalyse and discuss widely accepted conclusions of J&S in light of newly available information. Specifically, we will try to demonstrate that 1) Chilean predators may hunt for rabbits more frequently than J&S reported, 2) Spanish rabbits use open areas more often than J&S found, and 3) use of open areas by rabbits (at least in Spain) may be enhanced by presence of warrens, which are used as shelters.

Serotypes, toxins and antibiotic resistance of Escherichia coli strains isolated from diarrhoeic and healthy rabbits in Spain

The immunoreactivity of routinely processed liver and lung tissue samples obtained from rabbits inoculated with tissue explants from naturally infected animals when antisera directed against parvovirus from different species (canine, feline and porcine) as well as a RHD virus antiserum were employed has been tested by different immunoperoxidase methods. Cross-reactivity between RHD-virus antigens and parvovirus antigens was present. Best results were obtained with RHD and canine parvovirus antisera with the ABC method. The immunoreactivity in the liver was found in hepatocytes, Kupffer and bile duct cells. In the lung, it was exclusively observed in intravascular macrophages.