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

The three-dimensional analysis of gustatory papillae and its taste buds on the tongue of the wild-living hare (Lepus europaeus), European rabbit (Oryctolagus cuniculus), and domestic rabbit (Oryctolagus cuniculus f. domestica).

We propose that the worldwide spread of several viral diseases in European rabbits (Oryctolagus cuniculus) is facilitated by domestic rabbit meat production and associated international trade. This view is based on published records of the transfer of rabbit haemorrhagic disease viruses (RHDV/RHDV2) between countries and supported by data from the Food and Agriculture Organization (FAO) and the World Animal Health Information System (WAHIS) correlating the amount of rabbit meat produced and the number of rabbit haemorrhagic disease (RHD) outbreaks reported. Although RHDV was mainly confined to European rabbits, outbreak reporting rose after RDHV2 emerged and spread into many other lagomorph species. More than 80 species of native lagomorphs are now at risk from the disease in countries reporting RHD outbreaks. Our findings have implications for the maintenance of both industrial-scale cuniculture and village-scale production to combat poverty, for the future use of viruses for the biological control of pest rabbits and the conservation of native lagomorphs. Greater awareness of the risks of virus transfer in both directions between domestic rabbits and wild lagomorphs is important for future management of domestic rabbits and the conservation of native lagomorphs.

Morphological and molecular characteristics of a single oocyst for the identification of Eimeria species in domestic rabbits (Oryctolagus cuniculus f. domesticus)

Shope papillomavirus or cottontail rabbit papillomavirus (CRPV) is one of the first small DNA tumour viruses to be characterized. Although the natural host for CRPV is the cottontail rabbit (Sylvilagus floridanus), CRPV can infect domestic laboratory rabbits (Oryctolagus cuniculus) and induce tumour outgrowth and cancer development. In previous studies, investigators attempted to passage CRPV in domestic rabbits, but achieved very limited success, leading to the suggestion that CRPV infection in domestic rabbits was abortive. The persistence of specific anti-L1 antibody in sera from rabbits infected with either virus or viral DNA led us to revisit the questions as to whether L1 and infectious CRPV can be produced in domestic rabbit tissues. We detected various levels of L1 protein in most papillomas from CRPV-infected rabbits using recently developed monoclonal antibodies. Sensitive in vitro infectivity assays additionally confirmed that extracts from these papillomas were infectious. These studies demonstrated that the CRPV/New Zealand White rabbit model could be used as an in vivo model to study natural virus infection and viral life cycle of CRPV and not be limited to studies on abortive infections.

BackgroundNeospora caninum (N. caninum) has a broad intermediate host range and might cause multisystemic lesions in various species of animals. Dogs are both intermediate and definitive hosts of the parasite and play a crucial role in the horizontal transmission of this protozoan to other animals. Cats and rabbits could be sensitive to infection with N. caninum, however, clinical symptoms and the exact route of infection in these species are unknown. The epidemiology of N. caninum in cats and rabbits has been barely researched, and there is no published record of the seroprevalence of N. caninum infection in these species in Poland. Thus, the present study aimed to determine the frequency of seroreagents for N. caninum within pet dogs, cats and rabbits from urban areas of Poland and to identify possible risk factors for these animals.ResultsIn total, serum samples from 184 cats (Felis catus), 203 dogs (Canis familiaris) and 70 rabbits (Oryctolagus cuniculus) were used in the study. The seroprevalence of anti-N. caninum antibodies in dogs and cats reached 1.0% (2/203; 95% CI: 0.3–3.5) and 3.3% (6/184; 95% CI: 1.5–6.9), respectively. No significant differences in seroprevalence regarding age group, gender, symptoms or sampling location were found. All 70 samples from pet rabbits were negative for anti-N. caninum antibodies.ConclusionsThe seroprevalence rates of N. caninum in dogs and cats in the present study were low, however, our results confirmed N. caninum circulates among dog and cat populations in Poland, and neosporosis should be included in the differential diagnosis of neuro-muscular disorders in these species. This is the first serological survey of N. caninum in European pet cats and rabbits. The role of pet rabbits in N. caninum epidemiology and circulation in Poland is marginal.

Myxomatosis is a highly contagious viral disease caused by the Myxoma virus, affecting domestic and wild rabbits and resulting in severe skin lesions and high mortality. This study reports the first outbreaks of myxomatosis in domestic rabbits in Minas Gerais, Brazil, detailing clinical, pathological, epidemiological and molecular aspects. Two unrelated outbreaks occurred, with morbidity rates of 17.2% (15/87) in a research facility and 92.3% (12/13) on a small breeding farm. Clinically, affected animals exhibited lethargy, crusted and nodular skin lesions, particularly on the snout and ears, along with marked eyelid and genital oedema and hyperaemia. Histopathology revealed epidermal hyperplasia, keratinocyte degeneration, intracytoplasmic inclusion bodies and extensive myxomatous matrix deposition in the dermis. Diagnosis was confirmed by polymerase chain reaction and sequencing, showing phylogenetic similarity between Brazilian and European virus strains. These findings highlight the importance of improved surveillance and biosecurity to control the disease.

Treponema paraluisleporidarum infects both rabbits (ecovar Cuniculus) and hares (ecovar Lepus). While the occurrence of the bacterium has previously been reported for European brown hares (Lepus europaeus) and domestic rabbits (Oryctolagus cuniculus f. domestica), there are no data available that report infection in the European context. We tested a total of 1,995 serum samples and 287 genital swabs from opportunistically sampled European brown hares (Lepus europaeus; n = 2135), Mountain hares (Lepus timidus; n = 4), European rabbits (Oryctolagus cuniculus; n = 138), and pet rabbits (O. cuniculus f. domestica; n = 5). The samples originated from eight European countries. In case only serum was available, we tested the samples for the presence of anti-treponemal antibodies. For this, we utilized the Treponema pallidum-particle agglutination test (TP-PA), which is suited for the use in lagomorphs due to the antigenic cross-reactivity of anti-T. pallidum and anti-T. paraluisleporidarum antibodies. In addition, the results of 380 sera were confirmed using the fluorescent-Treponema antibody absorption test (FTA-ABS). In all cases where swab samples were available, DNA was extracted and tested using quantitative PCR to test for the presence of the lagomorph syphilis-bacterium. We were able to detect antibodies in 825 of 1,995 lagomorph sera (41.4%; brown hare: 825/1,868; rabbit: 0/127) and obtained positive qPCR results from 182 of 287 swab samples (63.4%; European brown hare: 167/267; mountain hare: 4/4; rabbit: 11/16). While all rabbit sera (n = 127) tested negative for anti-treponemal antibodies, the presence of the bacterium was confirmed in eight wild (n = 8/11) and three domestic rabbits (n = 3/5) from Germany using qPCR.

Cutaneous lymphoma is a common skin neoplasm of pet rabbits in Europe but is rarely reported in pet rabbits in North America. These neoplasms have not been previously characterized, nor has the cause for the apparent predilection for cutaneous lymphoma in European pet rabbits compared with North American pet rabbits been investigated. In this retrospective study, the authors morphologically and immunohistochemically characterized 25 cutaneous lymphomas in European pet rabbits according to the World Health Organization classification. Tumors were classified as diffuse large B cell lymphomas, with 14 lymphomas exhibiting a centroblastic/centrocytic subtype and 11 tumors exhibiting a T cell-rich B cell subtype. To investigate a potential viral etiology of these lymphomas, 3 diffuse large B cell and 3 T cell-rich B cell lymphomas were evaluated by polymerase chain reaction for retroviral and herpesviral genes. Neither virus was detected. In contrast to other domestic animals, cutaneous lymphomas in European pet rabbits were highly pleomorphic and frequently contained multinucleated giant cells. Unexpectedly, the second most common subtype was T cell-rich B cell lymphoma, a subtype that is rare in species other than horses. Based on a limited number of samples, there was no support for a viral etiology that would explain the higher incidence of lymphoma in European pet rabbits compared with American pet rabbits. Further investigation into genetic and extrinsic factors associated with the development of these tumors is warranted.

Simple SummaryThe study of European rabbit immunoglobulin genes has contributed decisively to the current knowledge on antibody structure and diversification. The European rabbit has also been increasingly used as an animal model for the study of many human diseases, such as syphilis, tuberculosis, and AIDS. As such, the study of its immune system genes is of crucial relevance, but the study of rabbit immunoglobulins has focused only on the IgG and IgA antibodies. In this study, we added to the knowledge of the rabbit immune system by investigating the genetic diversity of two antibodies, IgM and IgE, in wild and domestic rabbits as well as other rabbit close species. With the data obtained in this study, we showed a high similarity between the different rabbit close species studied and we pointed out important genetic differences in the wild and domestic rabbits. Our findings are a valuable tool for the management of rabbit wild populations and domestic breeds and may contribute to the identification of immunoglobulins genetic variants with greater efficiency against pathogens.The European rabbit (Oryctolagus cuniculus) has been an important model for immunological studies but the study of its immunoglobulins (Ig) has been restricted to its unique IgA and IgG. Here, we studied the genetic diversity of IgM and IgE in several species of leporids and performed population genetics studies on European rabbit wild populations and domestic breeds. The leporids sequencing showed that these Ig are well conserved (98% sequence similarity among leporids), For IgM the Cµ1 and Cµ4 were the most diverse and most conserved domains, respectively, while for IgE the Cε1 was the most diverse domain and Cε2 and Cε3 the most conserved domains. The differences in the pattern of most conserved and most diverse domain between the Ig isotypes are most likely related to each isotype function. The genetic population data showed contrasting results for IgM and IgE. For both Ig, as expected, a greater diversity was observed in the original species range, the Iberian Peninsula. However, unexpectedly the genetic diversity found for IgE in the domestic animals is higher than that for the French wild populations. These results will increase knowledge of the genetic diversity of leporids and wild and domestic rabbit populations and are important tools for the management of wild populations and rabbitries.

A soft tissue-filled external ear canal, sometimes also referred to as otitis externa in the veterinary literature, is a prevalent disease in pet rabbits, especially in lop-eared pet rabbits. The authors describe the clinical findings, diagnostic workup, therapy, and outcome of pet rabbits treated surgically for a lateral ear canal ablation (LECA). For the time period between 2015 and 2023, the medical records of two veterinary clinics were evaluated retrospectively. A total of 25 pet rabbits, diagnosed via computed tomography (CT) scans with a soft tissue-filled external ear canal and (if present) middle ear, were identified. All the pet rabbits were evaluated as lop-eared pet rabbits and all were treated surgically using the same surgical technique, LECA. In accordance with Richardson et al., we categorized the different ear filling levels by using the grading system that was established in 2019. The mean follow-up period was 19 days, and in one case complete wound healing was not reached within 131 days after surgery. A total of 7/25 of the pet rabbits were evaluated with wound healing issues. Of the cases, 18/25 did not develop any recurrent ear diseases. Loss to follow-up was observed in 5/25 of the cases and recurrent ear diseases were identified in 2/25 of the pet rabbits. Progression of the ear disease was detected in four cases. CT post-operative images were acquired for 14/25 of the pet rabbits. Based on this study, LECA can be considered a safe surgical method to treat soft tissue-filled external ear canals, especially in lop-eared pet rabbits. Nonetheless, thorough post-surgical management including wound control is critical for therapy success.

Rabbits have been categorised as low-risk animals for transmitting rabies. A case of a domestic rabbit (Oryctolagus cuniculus) with naturally acquired rabies infection that was diagnosed on postmortem using an Immunochromatographic test, Fluorescent Antibody Test, and RT-PCR has been reported here and its public health implications have been discussed. The report highlighted the importance of decision-making on the need of vaccinations in human exposure situations with these animals in endemic areas on a case-to-case basis. How to cite this article:Aparna S, Kumar GSA, AbrahamSS, Jose M. A Report of Rabies in a Domestic Rabbit (Oryctolagus cuniculus) and its Public Health Implications. APCRI J. 2022;24(2):7-9. DOI: https://doi.org/10.24321/0973.5038.202202

To optimize the use of CT-guided modeling for the calculation of body surface area (BSA) in domestic rabbits (Oryctolagus cuniculus). Animals-12 domestic rabbits. Adult rabbits (body weight, 1 to > 4 kg) that were client-owned animals undergoing CT for disease diagnosis or deceased laboratory animals donated from other research projects were scanned with a CT scanner. Images were transferred to a radiation therapy planning software program. Image slices were captured as contiguous slices at 100 kVp and 100 mA and processed to 0.1-cm-thick sections. The length of each contoured slice was summed to calculate a final BSA measurement. Nonlinear regression analysis was then used to derive an equation for the calculation of BSA in rabbits. The constant calculated by use of this method was 9.9 (range, 9.59 to 10). The R(2) for the goodness of fit was 0.9332. The equation that best described BSA as a function of body weight for domestic rabbits with this method was as follows: BSA = (9.9 × [body weight {in grams}](2/3))/10,000. The BSA calculated via the CT-guided method yielded results similar to those obtained with equations for other similarly sized mammals and verified the use of such equations for rabbits. Additionally, this technique can be used for species that lack equations for the accurate calculation of BSA.

Toxoplasmosis is a widely distributed disease that infects birds and mammals, including humans. Acute clinical course of toxoplasmosis is considered to be rare among domestic rabbits (Oryctolagus cuniculus). The aim of this study was to present the first report of fatal acute disease caused by Toxoplasma gondii type BrIII genotype, a typical Brazilian clonal lineage, in a domestic rabbit. T. gondii was identified in histological sections of spleen and liver tissue, and these tissues were also immunohistochemically positive for T. gondii. After the histopathological and immunohistochemical confirmation of T. gondii, the genotype of this pathogen was determined via PCR-RFLP with 11 markers (SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, Apico, and CS3) and via microsatellite (MS) analysis with 15 markers (TUB2, W35, TgMA, B18, B17, M33, IV.1, X1.1, M48, M102, N60, N82, AA, N61, and N83). This study shows that type BrIII genotype, circulating in Brazil in different hosts, can cause acute disease in a naturally infected animal host. The described case also involves the first reported occurrence of the 291 allele for the typing marker TUB2 in a type BrIII strain, emphasizing the genetic diversity of T. gondii in Brazil.

Validation of a minimally invasive blood-sampling technique for the analysis of hormones in domestic rabbits, Oryctolagus cuniculus (Lagomorpha)

To evaluate glomerular filtration rate (GFR) estimation by means of plasma clearance of iohexol (IOX) in domestic rabbits and to assess accuracy of limited-sampling models for GFR estimation. 6 healthy domestic rabbits (Oryctolagus cuniculus). Each rabbit received IOX (64.7 mg/kg [0.1 mL/kg], IV), and blood samples were collected at predetermined times before and after administration. Plasma IOX concentration was determined by high-performance liquid chromatography. The pharmacokinetics of IOX was determined by a noncompartmental method. For each rabbit, plasma clearance of IOX was determined by dividing the total IOX dose administered by the area under the concentration-time curve indexed to the subject's body weight. The GFR estimated from the plasma IOX concentration at 6 sampling times (referent model) was compared with that estimated from the plasma IOX concentration at 5 (model A), 4 (model B), and 3 (models C, D, and E) sampling times (limited-sampling models). Mean ± SD GFR was 4.41 ± 1.10 mL/min/kg for the referent model and did not differ significantly from the GFR estimated by any of the limited-sampling models. The GFR bias magnitude relative to the referent model was smallest for model D in which GFR was estimated from plasma IOX concentrations at 5, 15, and 90 minutes after IOX administration. Results suggested that plasma clearance of IOX was a safe, reliable, accurate, and clinically feasible method to estimate GFR in domestic rabbits. Further research is necessary to refine the method.