Renal pathology in wild European rabbits.

BACKGROUND: There is a relative paucity of data examining the prevalence of renal pathology in wild rabbits. METHODS: Sixty-two wild rabbits that had been shot for population control in Cambridgeshire, UK, underwent postmortem examination, including macroscopic and microscopic renal assessment. RESULTS: The majority (82%) of the animals had macroscopically and microscopically normal kidneys. One animal (1.6%) had severe perirenal abscessation. Pasteurella spp. was isolated from this lesion. Ten rabbits (16%) had microscopic renal pathology comprising minimal to mild renal inflammation or fibrosis. No Encephalitozoon cuniculi organisms were detected histologically. LIMITATIONS: The sample population was composed of shot rabbits, so the probability of detecting moribund individuals was reduced. Extrapolation of these data to the wider UK wild rabbit population may be limited as rabbits were shot at two sites within a 3 km radius of each other. CONCLUSION: Renal pathology is rare in the population examined.

[Ophthalmic findings caused by Encephalitozoon cuniculi (strain III) in a dog]. / Ophthalmologische Befunde durch Enzephalitozoon cuniculi (Stamm III) bei einem Hund.

A 2-year-old female mixed-breed canine patient from Namibia presented originally with chronic uveitis. A serum antibody titer and a PCR test performed on the aqueous humor were positive for encephalitozoon cuniculi. The left eye showed an immature anterior focal cortical cataract in the periphery with suspected lens capsule rupture and signs of chronic uveitis. An incipient anterior focal cortical cataract was also perceivable in the patient's right eye. Despite local treatment as well as systemic administration of carprofen, prednisolone, and fenbendazol recurrent uveitis occurred. The patient then underwent bilateral extracapsular lensextraction via phacoemulsification. A PCR test of the lens material was positive for encephalitozoon cuniculi strain III. Recurring uveitis and secondary glaucoma 10 months post-op resulted in permanent blindness of the left eye. The patient then continued to receive local anti-inflammatory treatment. The last recheck examination of both eyes, 31 month post-op, revealed no signs of uveitis. This is the first case reported of a cataract in a canine patient caused by encephalitozoon cuniculi strain III.

Distribution of M1 and M2 macrophages in cerebral granulomas caused by Encephalitozoon cuniculi.

Encephalitozoon cuniculi spores cause severe granulomatous inflammation in the brain where mononuclear cells and macrophages infiltrate. Here, we orally infected New Zealand white rabbits with 1 × 106E. cuniculi viable spores to study the recruitment and localization of macrophages in brain granulomas. At day 30 post-infection, the positive phenotype markers iNOS (M1) and Arg-1 (M2) were located in the periphery and center of granulomas, respectively. Live intracytoplasmic spores were found only in positive Arg-1 cells. This is the first work to describe the recruitment and distribution of M1 and M2 macrophages in the brain granulomas of rabbits infected with E. cuniculi.

A multidisciplinary review about Encephalitozoon cuniculi in a One Health perspective.

Encephalitozoon cuniculi is a microsporidian parasite mostly associated with its natural host, the rabbit (Oryctolagus cuniculus). However, other animals can be infected, like other mammals, birds, and even humans. Although it usually causes subclinical infection, it can also lead to encephalitozoonosis, a clinical disease characterized by neurological, ocular, and/or renal signs that can be even fatal, especially in immunocompromised individuals. Therefore, this multidisciplinary review contributes with updated information about the E. cuniculi, deepening in its molecular and genetic characterization, its mechanisms of infection and transmission, and its prevalence among different species and geographic locations, in a One Health perspective. Recent information about the diagnostic and therapeutic approach in the main host species and the prophylaxis and infection control measures currently suggested are also discussed.

Serological survey for antibodies to Encephalitozoon cuniculi and Toxoplasma gondii in pet rabbits in eastern coastal areas of China.

Encephalitozoon cuniculi (E. cuniculi) is a microsporidian parasite commonly detected in rabbits and can infect humans and cause encephalitozoonosis. And Toxoplasma gondii is a prevalent parasite distributed worldwide and can infect almost all warm-blooded animals, including humans. The aim of the current study was to investigate the seroprevalence of E. cuniculi and Toxoplasma gondii, and risk factors of infection in pet rabbits reared in eastern coastal areas of China (Tianjin, Shandong, Jiangsu, Zhejiang, Shanghai and Fujian). Total 222 blood samples of pet rabbits were collected from local veterinary hospitals. The seropositivity rates of E. cuniculi were 16.22% (36/222) according to an Enzyme-linked immunosorbent assay (ELISA). Female pet rabbits was significantly higher than that in males (P=0.002), Zhejiang were markedly higher than those in Jiangsu and Shanghai (P=0.017, P=0.022), and cross-breed rabbits were dramatically higher than those in Chinchilla, New Zealand white, Rex (P=0.02, P=0.006, P=0.008). The seroprevalence of T. gondii was 13.06% (29/222) by the method of ELISA. The seroprevalence in Zhejiang was significantly higher than that in Shanghai (P=0.017). No difference in seroprevalence was detected with respect to the gender, age, species, health status, or season. These findings show that E. cuniculi and T. gondii are present and spread in pet rabbits. Therefore, pet rabbits should be considered as an important reservoir of encephalitozoonosis for humans and maybe important implication for public health in eastern coastal areas of China.

Encephalitozoon cuniculi and Extraintestinal Microsporidiosis in Bird Owners.

We identified Encephalitozoon cuniculi genotype II parasites as a cause of extraintestinal microsporidiosis in 2 owners of birds also infected with E. cuniculi. Patients experienced long-lasting nonspecific symptoms; the disease course was more progressive in a patient with diabetes. Our findings suggest direct bird-to-human transmission of this pathogen.

Seroprevalence of Encephalitozoon cuniculi and Toxoplasma gondii antibodies and risk-factor assessment for Encephalitozoon cuniculi seroprevalence in Finnish pet rabbits (Oryctolagus cuniculus).

BACKGROUND: Neurological signs, such as head tilt, torticollis, paralysis, and seizures, are common in rabbits. Differential diagnoses include two zoonotic infections caused by the microsporidial fungi Encephalitozoon cuniculi and the apicomplexan protozoa Toxoplasma gondii. Both infections are mainly latent in rabbits but may cause severe or even fatal disease. Although several international studies have reported the seroprevalence of these pathogens in different commercial rabbit populations, similar prevalence studies and risk-factor analyses among family-owned pet rabbits are uncommon and lacking in Scandinavia. We sought to estimate the seroprevalence and possible risk factors for E. cuniculi and T. gondii among Finnish pet rabbits. We used ELISA to measure E. cuniculi IgG seroprevalence of 247 rabbits and modified direct agglutination test for T. gondii seroprevalence of 270 rabbits. Samples were collected as part of the Finnish Pet Rabbit Health Research project. Internet-based questionnaires (n = 231) completed by the rabbit owners were used for risk-factor analysis. RESULTS: The apparent seroprevalence of E. cuniculi was 29.2% and true seroprevalence of T. gondii 3.9%. Risk factors were analysed only for E. cuniculi due to the low T. gondii seroprevalence. The final multivariable logistic regression model revealed that rabbits spending the whole summer outdoors had a higher risk of being E. cuniculi seropositive than rabbits with limited outdoor access. Additionally, rabbits living in households with only one or two rabbits had higher risk of being E. cuniculi seropositive than those in multi-rabbit households. CONCLUSIONS: Nearly one third of Finnish pet rabbits participating in this study had E. cuniculi IgG antibodies, indicating previous exposure to this pathogen. The prevalence is similar to that reported previously in clinically healthy rabbit populations in UK and Korea. While the seroprevalence of T. gondii was low (3.9%), antibodies were detected. Therefore, these zoonotic parasitic infections should be considered as differential diagnoses when treating rabbits.

Mice with genetic and induced B-cell deficiency as a model for disseminated encephalitozoonosis.

Encephalitozoon cuniculi, an intracellular pathogen, lives in a balanced relationship with immunocompetent individuals based on the activity of T lymphocytes. We previously highlighted the greater susceptibility of B-1 cell-deficient mice (XID mice) to encephalitozoonosis. This study aimed to develop a model of disseminated and severe encephalitozoonosis in mice with combined immunodeficiency to elucidate the role of B cells. To address this objective, cyclophosphamide (Cy)-treated BALB/c and XID mice were inoculated with E. cuniculi, followed by the evaluation of the immune response and histopathological lesions. Immunosuppressed BALB/c mice manifested no clinical signs with an increase in the populations of T lymphocytes and macrophages in the spleen. Immunosuppressed and infected XID mice revealed elevated T cells, macrophages populations, and pro-inflammatory cytokines levels (IFN-γ, TNF-α, and IL-6) with the presence of abdominal effusion and lesions in multiple organs. These clinical characteristics are associated with extensive and severe encephalitozoonosis. The symptoms and lesion size were reduced, whereas B-2 and CD4+ T cells populations were increased in the spleen by transferring B-2 cells adoptive to XID mice. Moreover, B-1 cells adoptive transfer upregulated the peritoneal populations of B-2 cells and macrophages but not T lymphocytes and decreased the symptoms. Herein, we speculated the consistency in the development of severe and disseminated encephalitozoonosis in mice with genetic deficiency of Bruton's tyrosine kinase (Btk) associated with Cy immunosuppression develop with that of the models with T cell deficiency. Taken together, these data emphasized the crucial role of B cells in the protective immune response against encephalitozoonosis.

Molecular detection and genotype identification of E. cuniculi from pet rabbits.

Encephalitozoon cuniculi is a microsporidian which is frequently reported from rabbits. This microorganism can either ravage rabbit farms or transmit to humans from pet rabbits. This study aimed to investigate the prevalence and the genotype distribution of E. cuniculi among pet rabbits. In this study urine samples were collected from 50 pet rabbits, aged 2 months to 3 years, admitted to teaching veterinary hospital. Four races Lop, Dutch, Mix, and Angora were screened for E. cuniculi. The clinical symptoms were recorded and total DNA was extracted from urine samples. E. cuniculi was identified using amplification of the small subunit ribosomal RNA (ssu rRNA) gene and its genotypes were characterized using PCR/sequencing of the polar tube protein (PTP) gene. Phylogenetic tree was drawn to confirm the characterized genotypes. Out of 50 samples, 41 (82 %) of rabbits were asymptomatic, while nine (18 %) had at least one of symptoms including head-tilt, circling, and ataxia. A statistical correlation was seen between mean age + SD and symptoms (P-value = 0.039). The presence of E. cuniculi was confirmed in 16/50 (32 %) rabbits and all of them were identified as the genotype I. Our findings represented no consistency between E. cuniculi PCR - positive and the presence of symptoms (P-value = 0.318). Our results showed positive correlation between symptoms and age; however, the lack of correlation between PCR results with age may signify the latent infection in younger rabbits. All identified E. cuniculi were the genotype I, which is reported from rabbits and humans, highlighting the zoonotic concern for this genotype, particularly among subjects who keep pet rabbits.

Isolation of Streptococcus cuniculi from corneal lesion in laboratory-raised mice.

Corneal lesions appearing as white mass beneath intact epithelium, with ocular discharge in one mouse, was observed in a batch of laboratory-raised BALB/c mice (n=9 of 56). The affected mice remained active, well-groomed and had normal appetite. Isolates recovered from swab cultures of the external and internal contents of the eye had partial 16S rRNA gene sequence of 99.1% similarity to Streptococcus cuniculi. No previous report of S. cuniculi infection in laboratory rodents has been presented. The isolate was susceptible to all antibiotics tested. We suggest S. cuniculi is an opportunistic bacteria in laboratory mice but are uncertain of its source. Our findings revealed that S. cuniculi is able to colonize laboratory mice and should be considered when mice present with eye lesion or ocular discharge.

Encephalitozoon cuniculi infection in cats: European guidelines from the ABCD on prevention and management.

OVERVIEW: Encephalitozoon cuniculi is a common obligate intracellular microsporidian parasite of rabbits that is increasingly recognised as a pathogen of cats and other mammalian species. These guidelines aim to review the literature on feline E cuniculi infection and provide recommendations on prevention and management. INFECTION IN CATS: E cuniculi infection should be considered as a differential diagnosis in cases of feline uveitis and cataract formation. It is not significantly associated with either chronic kidney disease or meningoencephalitis. E cuniculi infection is more common in stray or feral cats than in pet cats. DIAGNOSIS AND TREATMENT: Serological tests for antibody detection in the blood are easy to perform and can be useful for diagnosis, but their specificity is low as antibodies have been found in apparently healthy cats. PCR appears to be more sensitive than histopathology for diagnosis, and is more sensitive when performed on cataractous lenses compared with aqueous humour, although ease of sampling is an obvious limitation. Treatment is with fenbendazole for 3 weeks and phacoemulsification to remove microsporidia from cataractous lenses. ZOONOTIC RISK: E cuniculi is a potential zoonotic agent, and there is a particular risk to immunocompromised humans posed by infected rabbits. Albeit infrequent, spore shedding has been identified in cats, so care should be taken around infected cats.

Characterization of humoral and cell-mediated immunity in rabbits orally infected with Encephalitozoon cuniculi.

Encephalitozoonosis is a common infectious disease widely spread among rabbits. Encephalitozoon cuniculi, is considered as a zoonotic and emerging pathogen capable of infecting both immunocompetent and immunocompromised hosts. The aim of the study was to describe in detail the spread of the E. cuniculi in a rabbit organism after experimental infection and the host humoral and cellular immune response including cytokine production. For that purpose, healthy immunocompetent rabbits were infected orally in order to simulate the natural route of infection and euthanised at 2, 4, 6 and 8-weeks post-infection. Dissemination of E. cuniculi in the body of the rabbit was more rapid than previously reported. As early as 2 weeks post-infection, E. cuniculi was detected using immunohistochemistry not only in the intestine, mesenteric lymph nodes, spleen, liver, kidneys, lungs and heart, but also in nervous tissues, especially in medulla oblongata, cerebellum, and leptomeninges. Based on flow cytometry, no conspicuous changes in lymphocyte subpopulations were detected in the examined lymphoid organs of infected rabbits. Cell-mediated immunity was characterized by ability of both CD4+ and CD8+ T cells to proliferate after stimulation with specific antigens. Th1 polarization of immune response with a predominance of IFN-γ expression was detected in spleen, mesenteric lymph nodes and Peyer's patches. The increased expression of IL-4 and IL-10 mRNA in mixed samples from the small intestine is indicative of balanced control of IFN-γ, which prevents tissue damage. On the other hand, it can enable E. cuniculi to survive and persist in the host organism in a balanced host-parasite relationship. The Th17 immunity lineage seems to play only a minor role in E. cuniculi infection in rabbits.

Encephalitozoon cuniculi infection in farmed rabbits in Egypt.

BACKGROUND: Encephalitozoon cuniculi is an important microsporidian parasite with zoonotic potential. The present study highlights the impact of encephalitozoonosis on rabbit health in Egypt. Three rabbit farms in Giza, with a total of 16,400 rabbits were investigated due to occurrence of rabbits displaying clinical signs consistent with encephalitozoonosis. RESULTS: Clinical signs observed during a 4 months observation period in 2018 included vestibular disease, paresis, limb paralysis, cataracts, phacoclastic uveitis, frequent urination, marked decrease in body weight and in some pregnant females, also repeated abortions. The total morbidity rates in adult and young rabbits were 76.7% and 81.5%, respectively. The highest mortality rate was recorded in offspring (12.3%), followed by dams (5.6%), and the lowest recorded mortality rate was in males (0.04%). Post-mortem findings included enteritis, pale enlarged kidneys, congested leptomeninges, focal brain necrosis, and endometrial congestion. Histopathological examination revealed nonsuppurative meningoencephalitis and glial nodules with central necrosis in the brain, vacuolation and necrosis of renal tubular epithelium, and corneal ulceration and ruptured lens capsule with fragmentation of lenticular fibres. E. cuniculi were observed in the brain, retinal ganglion cells, kidneys, and liver. Transmission electron microscopy examination revealed the presence of different developmental stages of E. cuniculi in the brain and kidney. Presence of E. cuniculi was confirmed by conventional polymerase chain reaction using a universal 16S gene for Encephalitozoon spp. followed by sequencing and sequence analysis. CONCLUSIONS: The presence of E. cuniculi in rabbits was confirmed at three farms in Egypt. Nervous signs and ocular lesions were the most predominant findings in these farms.

ENCEPHALITOZOON CUNICULI INFECTION IN A BLACK-FOOTED FERRET (MUSTELA NIGRIPES) KIT.

A 47-day-old black-footed ferret (Mustela nigripes) kit was found dead in June 2016. Histologic examination revealed pyogranulomatous tubulointerstitial nephritis, pneumonia, and encephalitis, with intralesional microsporidia. Transmission electron microscopic examination showed microsporidia with ultrastructural characteristics consistent with Encephalitozoon spp. Polymerase chain reaction (PCR) and direct sequencing confirmed the presence of Encephalitozoon cuniculi genotype II. This organism has been reported in other Carnivora (i.e., canids, felids, mustelids, procyonids, otariids). In humans, it is generally described as an opportunistic pathogen in immunocompromised individuals. The source of infection in the quarantine facility remains unknown, although two groups of frozen feeder rat kidneys tested positive for E. cuniculi genotype II via PCR. Feeding whole prey to various zoo taxa carries some potential disease transmission risk.

First insight into Encephalitozoon cuniculi infection in laboratory and pet rabbits in Iran.

Encephalitozoon cuniculi infects a wide variety of domestic and wild mammalian species including humans. Although the infection status has been studied in laboratory and pet rabbits worldwide, there is shortage of information regarding the disease in Iran. In the present study, the occurrence of infection in brains of 117 asymptomatic rabbits from six breeding and experimental units with highest population of rabbit colonies in the country (n = 60) as well as pet rabbits of pet stores in two cities (n = 57) were examined by nested-PCR. Histological sections of brains and kidneys were also studied by light microscopy. PCR results revealed that 3.3% of laboratory rabbits (2/60) and 59.6% of pet rabbits (34/57) harboured E. cuniculi in their brains. Histopathology on the other hand showed spores of the parasite in kidney and brain of one and kidney of another pet rabbit. As encephalitozoonosis may interfere with results of experiments performed on laboratory rabbits, routine screenings for identification and culling of infected animals is recommended. Furthermore, infected companion rabbits can transmit E. cuniculi to people in close contact with them, therefore, improving public knowledge of this zoonotic infection is suggested.

First molecular evidence of ocular transmission of Encephalitozoonosis during the intrauterine period in rabbits.

Many reports have been published on the suspected vertical transmission of Encephalitozoon cuniculi; however, prior to 2003, these reports were based on circumstantial evidence, such as histopathological, immunohistochemical, or serological diagnosis of the infection. In 2003, vertical transmission of the parasite was confirmed by detection of E. cuniculi DNA in fetuses with the nested polymerase chain reaction (PCR) technique. However, the passage of the parasite to eyes of fetus during the intrauterine stage still requires verification. In the current study, natively infected with parasite spores female rabbits were mated with non-infected males. All resulting offspring that died before ten postpartum days were investigated using molecular techniques to confirm the intrauterine transmission of the parasite to the offspring' eyes. In total, 119 DNA samples from rabbit offspring tissues were collected from blood, kidney, brain, eye (both eyes were used as single samples), lung, placenta, liver and heart were used for PCR. Parasitic DNA in the eyes of offspring was detected (54%) 6 of 11 naturally seropositive mother rabbits. PCR results were found to be positive for the eyes of 63% (19/30) of the offsprings from seropositive rabbits. Therefore, mother rabbits naturally infected with E. cuniculi showed the molecular presence of the parasite in their offspring' eyes. Sequence analysis confirmed the partial DNA sequence data of E. cuniculi and blast analysis identified the agent as genotype I. These results confirm transmission of E. cuniculi to rabbit offspring' eyes in the intrauterine period. This is the first molecular evidence to show ocular transmission of the infection via an intrauterine route in rabbits.

Intrapericardial Encephalitozoon pogonae-associated arteritis with fatal hemopericardium in two juvenile central bearded dragons.

Two male juvenile central bearded dragons ( Pogona vitticeps) were submitted for postmortem examination after dying at their respective homes. Dragon 1 had marked hemopericardium with restrictive epicarditis. The inner aspect of the distended pericardial sac was lined by a fibrinoheterophilic membrane. In addition, granulomas abutted the testes. Dragon 2 had acute hemopericardium and granulomatous arteritis of the great vessels exiting the heart. Histologically, both animals had granulomatous arteritis of the large arteries with intrahistiocytic gram-positive, slightly elongated, up to 2 µm long microorganisms that contained a vacuole. These microorganisms were also present in the paratesticular granulomas. On transmission electron microscopy, the microorganisms were identified as microsporidians given the presence of exospore, endospore, vacuole, nucleus, and a filament with 4-6 coils. The microsporidia were identified as Encephalitozoon pogonae based on sequencing of the internal transcribed spacer 1 of the ribosomal RNA genes. Microsporidia are agents of disease in bearded dragons. Intrapericardial arteritis of large arteries with hemopericardium or restrictive epicarditis is a fatal manifestation of this infection.

Toxoplasma gondii, Neospora caninum and Encephalitozoon cuniculi in Animals from Captivity (Zoo and Circus Animals).

Problems with parasitic infections are common in zoological gardens and circuses. In some animals it can lead to several disorders such as systemic disease, reproductive disorders (abortions and neonatal mortality), and even to death if severe illness is untreated. Thus, the aim of this study was to evaluate the prevalence of three common parasites in 74 animals from three zoos, and four circuses in Southern Italy. Antibodies to Toxoplasma gondii, Neospora caninum, and Encephalitozoon cuniculi were detected in 51%, 12%, and 20% of animals, respectively. Co-infections of T. gondii and N. caninum were reported in seven animals (9%) and co-infection of T. gondii and E. cuniculi in one animal. T. gondii, N. caninum and E. cuniculi seroprevalence differed in type of diet (P ≤ 0.0001; P ≤ 0.037 and P ≤ 0.004, respectively). T. gondii and E. cuniculi seroprevalence also differed in animal families (P ≤ 0.0001) and according to type of housing (P ≤ 0.003), respectively. Statistical differences were not found in other characteristics (gender, age, country of birth, origin, and contact with cats or dogs). This is the first serological study focusing on protozoan and microsporidian parasites in zoo and circus animals from Southern Italy and the first detection of antibodies to E. cuniculi in camels in Europe.

Encephalitozoonosis infection in a traditional rabbit farm with neurological manifestations.

Encephalitozoon cuniculi, a zoonotic and opportunistic pathogen, can cause latent infection, especially in lagomorphs. Nowadays, this member of the Eukaryotes has drawn significant attention in the fields of veterinary and public health. The purpose of this study was to determine the seroprevalence of infection in a New Zealand rabbit farm that has a clinical history of neurological manifestations including head tilt ataxia, aggressiveness, seizures, and circling and rotational movements around the body length axis, but the general conditions and food intake were normal. Blood samples were taken from 42 breeding rabbits and researched for E. cuniculi antibodies. Out of that, 25 (59%) animals resulted positive against the pathogen. The rabbit was found to be seropositive for E. cuniculi antibodies, but negative for Toxoplasma gondii and Listeria monocytogenes antibodies. Hematological and serum biochemical parameters were measured at reference intervals. No brain tissue impairment was observed the computed tomography (CT) scan. As a result of these histopathological findings, the brain cortex presented severe neuronal degeneration and partial myelin loss, with reactive diffuse gliosis against the parasite spores was observed to the histopathology. These results are possibly related to the early stage of infection because the parasitic infestation comprise long time spreading. E. cuniculi DNA was detected on brain tissues using polymerase chain reaction (PCR), and it partial DNA sequence was identified as E. cuniculi genotype I.