Seroprevalence of Encephalitozoon cuniculiand Toxoplasma gondiiantibodies and risk-factor assessment for Encephalitozoon cuniculiseroprevalence 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 cuniculiand 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. cuniculiand T. gondiiamong Finnish pet rabbits. We used ELISA to measure E. cuniculiIgG seroprevalence of 247 rabbits and modified direct agglutination test for T. gondiiseroprevalence 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. cuniculiwas 29.2% and true seroprevalence of T. gondii3.9%. Risk factors were analysed only for E. cuniculidue 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. cuniculiseropositive than rabbits with limited outdoor access. Additionally, rabbits living in households with only one or two rabbits had higher risk of being E. cuniculiseropositive than those in multi-rabbit households. Conclusions: Nearly one third of Finnish pet rabbits participating in this study had E. cuniculiIgG 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. gondiiwas low (3.9%), antibodies were detected. Therefore, these zoonotic parasitic infections should be considered as differential diagnoses when treating rabbits.