The seroprevalence of Encephalitozoon cuniculi among healthy pet rabbits in Norway

Abstract

Encephalitozoon cuniculi is a spore-forming obligate intracellular parasite, belonging to the genus Microsporidia. It is zoonotic and can infect both humans and other species with immunocompromised individuals being especially susceptible. The pathogen is a source of disease in pet rabbits (Oryctolagus cuniculus) and targets several organs typically including the brain, eyes and kidneys. Clinical signs of encephalitozoonosis often observed include head tilt, ataxia, swaying, uveitis or polyuria, and severe infection may lead to death. Clinical diagnosis is challenging due to many differential diagnoses and the fact that E. cuniculi can give an asymptomatic chronic infection with antibody response. In this study serum samples from 105 clinically healthy pet rabbits from six counties in Southern Norway were analysed for IgG (Immunoglobulin G) and IgM (immunoglobulin M) antibodies against E. cuniculi by an Immunofluorescent antibody test (IFAT). The results revealed the antibody prevalence to be 59% (62/105). In regard to specific antibodies, 5% (5/105) had elevations in IgM antibodies only, 38% (40/105) in IgG antibodies only and 16% (17/105) had elevations in both IgG and IgM antibodies. No risk factors such as gender, diet, living conditions or access to direct sunlight showed correlation with being infected with E. cuniculi. There were no obvious geopgraphical differences in seroprevalence. The findings of this study showed E. cuniculi to be a widespread pathogen in the healthy rabbit population in Southern Norway.