Technical advancements have enabled the discovery of potential pathogens in an ever-broadening range of wildlife taxa. To further the scope of this body of knowledge and to inform conservation efforts, we examined potential disease agents present in swamp rabbits (Sylvilagus aquaticus) of southeastern Missouri, USA, during winter 2023. This region represents the northernmost portion of the species' range and is characterized by an intermixed landscape of preferred bottomland hardwood forest and agricultural landcover. Concerns about infectious disease threats to swamp rabbits have increased since the emergence of rabbit hemorrhagic disease, caused by rabbit hemorrhagic disease virus 2 (RHDV2; Caliciviridae, Lagovirus europaeus), that has spread to domestic, wild, and feral rabbits and hares, predominantly in the western and midwestern USA. We applied metagenomic and metabarcoding methods, designed to characterize communities of viruses and parasites, to noninvasively collected rabbit fecal samples. We identified seven viruses and eight parasite genera that probably infect mammals. Although some relatives of these agents cause disease, none are unexpected in lagomorphs, and none are considered a health concern. Notably, RHDV2 was not detected. These results provide baseline data for future conservation and management efforts, especially if RHDV2 or other pathogens become a concern for swamp rabbits.

Informed ownership and lower social deprivation are associated with provision of preventative healthcare for pet rabbits.

Extreme cephalic conformation has been theorised to be associated with compromised health in rabbits. However, recognition and assessment of such phenotypes remain largely subjective. This study aimed to develop and validate a visual, semi-quantitative system for head shape phenotype in rabbits. Images of rabbits were collected and visually analysed for comparative phenotypic patterns, with a 1-5 grading scale subsequently created. Initial validation of the system was conducted via an online pilot survey across 24 experienced individuals. Interobserver agreement across scores was calculated to assess the reliability of the system. The proposed system yielded strong, 'almost perfect' and statistically significant interobserver agreement for cephalic assessment (W = 0.908, 95% bias-corrected and accelerated [BCa] confidence interval [CI]: 0.858-0.950; α = 0.880, 95% CI: 0.875-0.885), with largely positive feedback from veterinary professionals. Further development and validation of the system are required for complete, reliable assessment of all rabbits, particularly those with longer fur. Wider participation in the validation of this method from across the profession is also necessary. This system has the potential to enhance conformational assessment in rabbits. Implementation of the system in clinical practice may help to promote awareness of potential conformation-associated health risks and catalyse discussions regarding responsible ownership. The system may also support further studies into the precise influence of conformation on disease risk.

To evaluate whether rabbit-appeasing pheromone (RAP) use can help pet rabbits cope with transport. This controlled experimental study was performed from April 18 through June 12, 2024. Rabbits underwent a 30-minute car trip in a crate sprayed with RAP in mist form or the control. Rabbits were video recorded to assess their behavior. Blood was sampled 2 days before transport, immediately after, 2 days after, and 8 days after to dose corticosterone. Statistical analysis was performed to assess differences between groups. Twenty-four 5-month-old New Zealand white rabbits (6 castrated males, 6 entire males, and 12 entire females) were divided between RAP (n = 12) and control (12) groups. Video analysis revealed that controls kept ears pushed back longer than RAP-treated rabbits (mean difference, 512.88 seconds; 95% CI, 64.39 to 961.38 seconds), and they also tended to be more agitated (mean difference, 88.71 seconds; 95% CI, -7.62 to 185.05 seconds), whereas RAP-treated rabbits kept ears in erect position longer (mean difference, 544.47 seconds; 95% CI, 111.56 to 977.39 seconds). The RAP group tended to have higher corticosterone levels after transport compared to the controls (mean difference, 33.14 ng/mL; 95% CI, -5.64 to 71.93 ng/mL), but levels became equivalent after 2 and 8 days. The results indicate that RAP modified the rabbit behavior and neuroendocrine stress response, suggesting a shift toward an adaptive coping strategy in response to transport. Spraying RAP into the transport crate seems to be a promising method in helping pet rabbits cope with this event.

Cutaneous and subcutaneous soft tissue sarcomas of undetermined differentiation are common in pet rabbits and are often diagnosed as sarcoma not otherwise specified (sarcoma NOS). Such sarcomas with marked cellular pleomorphism and presence of multinucleated giant cells are also referred to as undifferentiated pleomorphic sarcoma, anaplastic sarcoma, or giant cell sarcoma. However, these terminologies do not define any cellular differentiation. In this study, we aimed to identify the line of differentiation of cutaneous pleomorphic sarcomas in rabbits. Histopathological, histochemical, and immunohistochemical analyses were performed on 48 cutaneous masses in rabbits, previously diagnosed as sarcoma NOS. Histologically, the tumors were characterized by proliferation of pleomorphic mesenchymal cells, primarily spindle cells, with frequent presence of multinucleated giant cells (58% of the cases). Sirius red staining revealed fine collagen fibers directly extending from the neoplastic cells in all cases. Some cases showed immunoreactivity for calponin (35%), α-smooth muscle actin (31%), and pan-muscle actin (25%). Almost all the case were negative for SOX10, ionized calcium binding adapter molecule-1 and CD204. Based on the findings above, rabbit cutaneous pleomorphic sarcomas are considered to differentiate towards fibroblasts and/or myofibroblasts. In addition, our follow-up data revealed a high recurrence rate and short survival times, indicating aggressive biological behavior of rabbit cutaneous pleomorphic sarcomas.

Rabbits' teeth grow continuously. Overgrown teeth are a frequent cause for veterinary consultation and can have severe welfare implications. The risk factors for overgrown teeth are incompletely understood. Rabbits with overgrown teeth recorded in their electronic health records (EHRs) were identified from a large population of rabbits presenting to veterinary practices (2014-2023). A case‒control study was used to evaluate associations with animal-level characteristics. A total of 1272 narratives describing overgrown teeth in 749 individual rabbits were identified, with incisor involvement in 67.7% of the cases. The proportion of recorded tooth-shortening methods involving clipping declined from 21.4% in 2014 to 4.2% in 2021, with no cases recorded in 2022. Brachycephaly (odds ratio [OR] 1.63, 95% confidence interval [CI] 1.21-2.20), increasing age (OR per 1-year increase 1.08, 95% CI 1.05-1.10) and male sex (OR 1.80, 95% CI 1.45-2.23) were associated with higher odds of dental overgrowth. Neutered rabbits had lower odds of dental overgrowth (OR 0.68, 95% CI 0.55-0.83). The study relied on retrospective EHR data. Misclassification of phenotypes may have arisen from incomplete or incorrect recording in the data. Targeted education and preventative health messaging around dental overgrowth may help mitigate the associated welfare implications in pet rabbits.

Floppy rabbit syndrome (FRS) is known as an idiopathic neurological condition with a peracute onset of tetraparesis. While there are several anecdotal reports mentioning this phenomenon, scientific literature on this subject is scarce. The aim of this study was to assess clinical and clinicopathological data as well as the outcome of patients with FRS. This retrospective study included pet rabbits that presented with a peracute progressive symmetric lower motor neuron tetraparesis characterised by generalised weakness in all four limbs and decreased muscle tone and spinal reflexes. History, clinical signs, laboratory results, treatment and outcome were analysed. The data revealed nine rabbits with non-ambulatory tetraparesis resembling FRS. Otherwise, the rabbits presented clinically unremarkably. All the animals showed significantly increased serum creatine kinase (CK) concentrations. Eight out of nine rabbits fully recovered within a short period. The study is limited by the small number of patients and the absence of muscle biopsy results and electromyography. FRS can be clearly diagnosed due to its typical consistent clinical presentation and neurological examination. Clinical pathology, including the determination of serum CK concentrations, may aid in differentiating FRS from other diseases. FRS is typically self-limiting idiopathic neuromuscular disease that does not require specific treatment; therefore, euthanasia should be avoided.

We report the draft genome sequences of three Enterococcus strains isolated from the gastrointestinal tract of domestic rabbits. These genomes contribute to expanding the representation of Enterococcus diversity in non-conventional hosts and provide resources for future comparative and functional genomics of gut-adapted Enterococci.

Over the last decades, the population of pet rabbits in Europe has increased significantly, but to date studies into feeding management of these species have been mainly conducted in production animals. This study aimed to evaluate the feeding practices of both pet rabbit owners and hobby breeders in Germany and how these may affect animal health. For this purpose, a survey was conducted from July to August 2020 to collect data regarding breeding, nutritional management and animal health: 431 participants replied. Results obtained from the questionnaires highlighted several differences. Based on our results, hay is provided in large amounts by almost all participants, meeting the rabbits' need for high fibre intake. However, rabbit breeders typically provide less hay and fresh food (e.g. grass, herbage, forage plants, vegetables, fruit), and more concentrates (e.g. pellets, muesli, commercial mixes, cereals) than pet rabbit owners. Gastrointestinal (GI) diseases were common in both groups. A link was noted between feeding practices and health conditions like diarrhoea, constipation, being overweight, dental problems and the development of urolithiasis. Although recent data on rabbit obesity indicate an increasing prevalence of this condition, most breeders and owners consider their animals' body condition to be normal. Nevertheless, in this study, obesity was associated with individual housing, which is more used by hobby breeders. Results from this study suggest that owners and breeders manage rabbit feeding differently and that these choices may impact animal health.

Significant Sarcoptes scabiei infestation in rabbits (Oryctolagus cuniculus): effects on physiological, apoptotic, histological, immunohistochemical, and growth performance indices.

Potassium homeostasis is essential for maintaining membrane potential and normal neuromuscular function. Although potassium disturbances are clinically relevant in several species, their prevalence and prognostic significance in pet rabbits remain poorly characterized. This retrospective study evaluated plasma potassium concentrations at admission in 1773 venous samples from 1312 pet rabbits and assessed associations with mortality, glycemia, and renal markers (BUN and creatinine) using an i-Stat portable analyzer. Normokalemia (3.4-5.7 mmol/L) was observed in 78.1% of samples, while hypokalemia and hyperkalemia occurred in 13.9% and 8.0%, respectively. Overall, 7-day mortality was 21.3%, with most deaths (68.7%) occurring within 48 h. Both hypo- and hyperkalemia were associated with increased mortality, with hyperkalemia conferring the greatest risk (relative risk of up to 5.4 at 24 h; p < 0.0001). Potassium concentrations were higher in non-survivors at all time points. Hyperkalemia was also associated with hypoglycemia and azotemia (p < 0.0001), suggesting impaired renal potassium excretion and possible alterations in insulin-mediated cellular potassium uptake. No consistent association was observed between hyperglycemia and hyperkalemia. These findings indicate that plasma potassium disturbances are common in pet rabbits and are associated with short-term mortality and metabolic derangements. Early identification and correction of potassium imbalances and their causes may improve outcomes in critically ill rabbits.

ABSTRACT Aims To identify some of the risk factors for dental malocclusion and examine associations between diet, age and sex and the frequency of dental malocclusion in a convenience sample of pet rabbits (Oryctolagus cuniculus) in Lima, Peru, during the period 2021–2022. Methods A cross-sectional study of clinical records of 308 rabbits at a private veterinary clinic in Lima, Peru from May 2021 to May 2022 was undertaken. The χ2 test was used to determine the unadjusted associations between variables and the diagnosis of dental malocclusion. Crude prevalence ratios (cPR) and adjusted prevalence ratios (aPR) were calculated using a generalised linear model with a Poisson distribution. Results The frequency of dental malocclusion in the sample was 75/308 (24.4%). The aPR for dental malocclusion for males was 1.80 (95% CI = 1.10–2.95) times higher compared to females, 1.94 (95% CI = 1.13–3.34) times higher for rabbits > 5 years old (seniors) compared to rabbits < 1 year old (juveniles) and 0.37 (95% CI = 0.25–0.54) times lower for a diet with hay compared to a diet without hay. Conclusions Our data and model suggest that senior, male rabbits on a diet without hay would have a higher frequency of malocclusion than female, juvenile rabbits on a diet including hay. After adjusting for age and sex, hay in the diet decreased the occurrence of dental malocclusion. Clinical relevance Our results contribute to the limited studies about the dental health of pet rabbits and may be a source of information for veterinarians and pet owners who seek optimal pet health and welfare.

To evaluate the clinical use, indications, outcomes, and adverse reactions associated with allogenic whole blood transfusions in domestic rabbits (Oryctolagus cuniculus). A retrospective cohort of client-owned rabbits receiving allogenic whole blood transfusions at a veterinary teaching hospital between 1993 and 2025 was identified. Signalment, transfusion indications and parameters, and survival to discharge were collected. Adverse reactions were graded based on canine and feline consensus guidelines including imputability and severity scores. 21 rabbits were included. The most common indication for transfusion was blood loss from liver lobe torsion (10 of 21 [48%]) or intraoperative blood loss (6 of 21 [29%]). Results from crossmatching, performed in 62% of cases (13 of 21), were negative in all cases. Adverse reactions occurred in 10 of 21 rabbits, with 14 total adverse reactions reported. Transfusion-associated dyspnea (5 of 21 [24%]) and transfusion-associated cardiac overload (5 of 21 [24%]) occurred most frequently. All reactions were classified as nonsevere (9 of 14 [64%]) or severe (5 of 14 [36%]) and assigned imputability scores of possibly (9 of 14 [64%]) or probably (5 of 14 [36%]) related to the transfusion. Overall survival to discharge was 57% (12 of 21). Allogenic whole blood first transfusions in domestic rabbits appeared clinically effective and generally well tolerated, with improved PCV and no life-threatening complications. Rabbits had a higher rate of acute respiratory signs during or after transfusion compared to dogs or cats. Whole blood transfusion was a feasible, potentially lifesaving treatment in critically ill rabbits. Future studies should prospectively collect data to better characterize transfusion reactions in this species and allow optimization of protocols.

To determine whether an elevated rectal temperature is a predictor of survival in ill pet rabbits. Secondary aims were to identify risk factors associated with pyrexia in rabbits and to categorize the associated differential diagnoses. A retrospective cohort study was performed of 70 clinically ill pet rabbits treated at an exotics specialist hospital in Sydney, Australia, between 2018 and 2024. Thirty-five pyrexic rabbits (rectal temperature ≥ 40.0 °C) were temporally matched with 35 normothermic controls (38.0 to 39.9 °C). Data were collected with a systematic database search and included sex, neuter status, age, breed, rectal temperature, suspected diagnosis, and survival outcome. Rabbits lacking adequate follow-up were excluded. Logistic regression models analyzed associations between rectal temperature, survival, and risk factors. Pyrexic rabbits were 1.27 (95% CI, 1.03 to 1.57) times more likely to die than normothermic rabbits and 4.52 (95% CI, 1.34 to 18.3) times more likely to have a poor outcome (euthanized or died). Each 1 °C increase in rectal temperature was associated with a 2.48-fold increase in chance of mortality (95% CI, 1.17 to 5.27). Neuter status was significantly associated with increased rectal temperature. Infectious disease accounted for 54.3% of pyrexia cases. Increased rectal temperature should be considered a significant finding when assessing the severity of illness and potential outcomes in clinically ill pet rabbits. Rectal temperature measurement is a simple, accessible prognostic tool that can assist clinicians with triage, treatment planning, and client communication. Infectious disease should be prioritized as a differential diagnosis in rabbits with pyrexia.

Functional and Genomic insights into probiotic Lactic Acid Bacteria isolated from the Gastrointestinal microbiota of domestic rabbits (Oryctolagus cuniculus)

Myxomatosis is a severe viral disease of lagomorphs that has recently seen the emergence of a recombinant myxoma virus (MYXV). Data from Africa remain scarce. Here we report the first confirmed detection and genomic characterization of a recombinant MYXV in Algeria. Two domestic rabbits from a backyard smallholding in El Affroun (Blida province) were presented on 19 October 2022 with classical signs of myxomatosis, including marked facial edema, severe mucopurulent blepharoconjunctivitis, and respiratory involvement. Necropsy and histopathology showed lesions typical of myxomatosis (epithelial hyperplasia with ballooning degeneration, intracytoplasmic inclusions, ulceration, stromal expansion by myxoma cells, and vascular hyperemia and leukostasis). MYXV DNA was detected in multiple tissues from both animals, and virus isolation on RK‐13 cells produced cytopathic effects (CPEs) by days 5–7 postinoculation. The Algerian MYXV sequence showed >99.9% nucleotide identity to the MYXV Toledo strain (GenBank Accession Number MK836424.1). Phylogenetic analysis placed the Algerian strain within the recombinant ha‐MYXV cluster, between earlier Spanish sequences (2018) and more recent Northern European sequences (2024), with the most recent common ancestor estimated around January 2017 (95% HPD July 2015–May 2018). These findings extend the known range of recombinant MYXV beyond Europe and highlight introduction risks at the pet–farm–wildlife interface in North Africa. We recommend strengthened vaccination of pet and farmed rabbits, pragmatic biosecurity in smallholdings, and targeted surveillance of hare populations to clarify sources and transmission routes.

Toxoplasma gondii is a protozoan parasite with high zoonotic potential. Currently, no information is available on natural toxoplasmosis in domestic rabbits in Romania; therefore, the aim of the present study was to evaluate the seroprevalence of T. gondii IgG antibodies and to determine the prevalence of T. gondii DNA in domestic rabbits in our country. In total, 372 domestic rabbits were tested. Blood samples were obtained from 352 animals and tissue samples were obtained from 49 animals, of which 29 animals provided paired blood-tissue samples. Samples were collected from pet rabbits and from rabbits raised in household settings, hereafter referred to as farm rabbits. Sera samples were analyzed using a modified agglutination test (MAT), with a cut-off of 1:24, for anti-T. gondii antibody IgG-type detection, and the tissue specimens were tested by nested polymerase chain reaction (nested PCR) targeting the B1 gene for T. gondii DNA detection. A seropositivity of 16.5% (58/352) was obtained by MAT, while the prevalence of T. gondii DNA was 4.1% (2/49). The present study highlighted the presence of T. gondii in domestic rabbits in Romania, which suggests that rabbit meat consumption may represent a potential risk to human health and therefore warrants further attention. Moreover, to the best of our knowledge, this is the first study to report data on the prevalence of T. gondii in domestic rabbits from Romania.

This study aimed to describe the normal radiographic anatomy of relevant thoracic structures in clinically healthy pet rabbits and provide morphometric data for some of these structures in lateral and ventrodorsal radiographs. Radiographs of 100 pet rabbits without clinical or radiographic signs of respiratory, cardiovascular, or mediastinal diseases were included in the study. The radiographic appearance of the aorta, the caudal vena cava, pulmonary vessels, the trachea, the delineation (visibility) of the cranial heart contour, and the extension of the diaphragm were evaluated using lateral radiographs. Additionally, the height of the trachea at 2 locations and the angle between the trachea and the thoracic spine were measured. On radiographs in ventrodorsal projection, the visibility of the cranial cardiac contour, the shape of the thorax, and the extension of the diaphragm were evaluated. Thoracic radiographs of 100 pet rabbits, including 54 males (14 intact and 40 neutered) and 46 females (29 intact and 17 neutered) were included. The animals were aged between 6 months and 11 years (median 4.75 years) and had a median body weight of 1.8 kg (range: 0.8-2.7 kg). On the lateral projection, the aorta and vena cava were visible on all radiographs, whereas small pulmonary vessels were recognizable in only 61 animals. The cranial contour of the heart was well defined in 45 rabbits and moderately defined in 55 rabbits. The trachea was exclusively ventrally mineralized in all rabbits. Median tracheal height was 3.2 mm at the level of the first thoracic vertebra and 3.2 mm at the level of the fourth thoracic vertebra. The median angle between the trachea and thoracic spine was 11.6°. On the ventrodorsal projection, the cranial contour of the heart was well defined in 74 rabbits and moderately in 26 rabbits. The median diaphragmatic extension was at the level of the 7th thoracic vertebra. Our study provides an overview of the thoracic structures visible on radiographs in pet rabbits weighing up to 3 kg. The results of our study contribute to the detection of pathological changes in the thorax.

Suspected lung lobe torsion and successful lobectomy in a domestic rabbit (Oryctolagus cuniculus)

Neurological examination in pet rabbits aims at localizing lesions within the nervous system in order to determine differential diagnoses and appropriate further diagnostics. Due to species-specific behavior and anatomical differences, the standard examination protocol used in small animals requires modification. In 2 published studies involving clinically healthy pet rabbits, several neurological tests were found to be either non-applicable or to require adjustments. The examination includes the assessment of consciousness and behavior, posture, gait, cranial nerve function, postural reactions, as well as spinal reflexes. Certain tests, such as the menace response and some placing reactions of the hind limbs, were not consistently elicitable. Others, such as the wheelbarrow test, hemiwalking, and the righting response, were performed reliably. The systematic validation of neurological tests for the diagnosis of specific neurological disease in rabbits is still lacking to date. Neuroanatomical localization is therefore carried out in the same way as for dogs and cats. Paresis or paralysis and vestibular signs are the most common neurological signs in rabbits. Differentiation between upper (UMN) and lower motor neuron (LMN) lesions allows localization to specific spinal cord segments or to the neuromuscular structures. Common causes of paresis/paralysis include traumatic or inflammatory myelopathies. Vestibular signs require localization to the central or peripheral components of the vestibular system.