Seroprevalence of Encephalitozoon cuniculi Infection in Pet Rabbits in Brazil

Occurrence of Encephalitozoon cuniculi and Encephalitozoon hellem in European Wild Rabbits (Oryctolagus cuniculus) in Southern Germany (Bavaria)

Encephalitozoon cuniculi and Encephalitozoon hellem are fungus-related, obligate intracellular pathogens belonging to the microsporidia. Both microorganisms occur in mammals, birds and even humans, thus revealing a zoonotic potential. Knowledge of their relevance in wild rabbits is very limited so far. Thus, the aim of the present study was to investigate the occurrence of E. cuniculi and E. hellem in wild rabbit populations in southern Germany (Bavaria). Therefore, blood and organ samples (brain/kidney) of 158 wild rabbits were investigated by immunofluorescence and PCR-based assays. Antibodies to E. cuniculi were detected in 24 of the 158 (15.2%) wild rabbits, while DNA of E. cuniculi was found in 7 (4.4%) and DNA of E. hellem was found in 3 (1.9%). Sequencing identified E. cuniculi genotype 1. This study provides the first E. cuniculi genotype determination in free-living wild rabbits worldwide and the first evidence of E. hellem in rabbits worldwide. Wild rabbits should, therefore, be regarded as a reservoir for both pathogens and, on the basis of molecular evidence from kidney tissue and presumed urine excretion, also as a source of infection for E. cuniculi for animals and humans.

Association of Encephalitozoon cuniculi with Clinical Signs and Abnormal Hematologic/Biochemical Changes in Pet Rabbits in Thailand

Encephalitozoon cuniculi can cause serious disease and subclinical infection in rabbits and requires active surveillance to control the infection. This study investigated the association between anti-Encephalitozoon cuniculi antibody status and various health parameters in pet rabbits. A total of 90 rabbits were divided into healthy (N = 30), subclinical (N = 30), and clinical (N = 30) groups based on their anti-Encephalitozoon cuniculi antibody status and clinical presentations. The mean ages of the control (37 ± 40 months) and subclinical groups (38 ± 34 months) were notably lower compared to that of the clinical group (63 ± 38 months, p < 0.01). Serum titers for anti-Encephalitozoon cuniculi antibodies were significantly elevated in rabbits with subclinical and clinical infections compared to those of healthy rabbits (p < 0.05). Neurological signs were predominant in rabbits with active E. cuniculi infection (80.0%), with additional pathological features including urinary dysfunction (10.0%) and cataracts (10.0%). The source of rabbits was not associated with E. cuniculi infection (p = 0.159). Anemia was significantly linked to E. cuniculi infection (p = 0.026); however, no significant associations were found with leukocytosis, thrombocytopenia, or serum biochemistry parameters. Mature adult rabbits were more likely to be infected with E. cuniculi. Recognizing anemia and neurological signs facilitates in early diagnosis of E. cuniculi infection.

The Prevalence of Encephalitozoon cuniculi in Domestic Rabbits (Oryctolagus cuniculus) in the North-Western Region of Romania Using Serological Diagnosis: A Preliminary Study

Encephalitozoon cuniculi is a microsporidian, domestic rabbits being the main host. The disease can be acute or subclinical, but treatment options are limited and usually with unrewarding results; therefore, diagnosis and prevention of encephalitozoonosis in rabbits are of the utmost importance. This study aims to obtain the first preliminary information of the prevalence of E. cuniculi in the north-western region of Romania. A total of 176 rabbits were clinically examined and 2 mL of blood was sampled from each. An enzyme-linked immunosorbent assay (ELISA) kit by Medicago (Medicago, Uppsala, Sweden) on the resulted blood serum was utilized. Statistical analysis of the results was conducted using the EpiInfo 2000 software (CDC, Atlanta, GA, USA). A total prevalence of 39.2% (69/176) was identified, with statistically significant differences in relation to the rabbits' clinical status, age, season of sampling, breeding system, body condition score and county of origin; the different family farms tested also had a statistically significant difference. This study gives the first preliminary information on this pathogen distribution on Romania's territory, but further studies need to be performed on larger regions to declare the prevalence in the country.

A Review of Encephalitozoon cuniculi in Domestic Rabbits (Oryctolagus cuniculus)-Biology, Clinical Signs, Diagnostic Techniques, Treatment, and Prevention

Encephalitozoon cuniculi is a eukaryote, unicellular, spore-forming, obligate intracellular microorganism of the phylum Microsporidia, with domestic rabbits as its main host. Another important species in which this pathogen has been identified are humans, the infection being therefore called a "zoonosis". The transmission takes place via the horizontal route or the vertical route, and cell-mediated immunity plays the biggest role in the infected hosts' protection. Encephalitozoonosis can manifest itself as an acute infection, with neurological signs, renal signs, and ocular lesions, or as a chronic or subclinical infection, which is usually the case for asymptomatic carriers. The diagnostic techniques usually carried out are histological examination, serological tests, and molecular genetic techniques. The treatment of encephalitozoonosis is usually symptomatic, with unrewarding results, and prevention methods include periodical serological screening, prophylactic administration of fenbendazole, and maintenance of a clean environment. The purpose of this article is to review the current data regarding the pathogenesis, host immunity, clinical signs, diagnostic methods, treatment, and prevention methods of encephalitozoonosis in the domestic rabbit, as well as to analyze the prevalence of this disease in different countries of the world.

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.

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.

Microsporidiosis in Vertebrate Companion Exotic Animals

Veterinarians caring for companion animals may encounter microsporidia in various host species, and diagnosis and treatment of these fungal organisms can be particularly challenging. Fourteen microsporidial species have been reported to infect humans and some of them are zoonotic; however, to date, direct zoonotic transmission is difficult to document versus transit through the digestive tract. In this context, summarizing information available about microsporidiosis of companion exotic animals is relevant due to the proximity of these animals to their owners. Diagnostic modalities and therapeutic challenges are reviewed by taxa. Further studies are needed to better assess risks associated with animal microsporidia for immunosuppressed owners and to improve detection and treatment of infected companion animals.