Usefulness of detection of specific IgM and IgG antibodies for diagnosis of clinical encephalitozoonosis in pet rabbits

Abstract

Encephalitozoon cuniculi is an obligate intracellular pathogen that has wide host distribution, but primary affects rabbits. This study presents a seroepidemiological study of E. cuniculi infection in 500 pet rabbits from the Czech Republic using ELISA capable of measuring IgM and IgG antibodies. Specific IgM antibodies, reflecting acute, reactivated infection or reinfection, were detected in 32.4% of all rabbits. IgG antibodies indicating chronic infection, were presented in 68.0% of all rabbits. The highest detection rate of IgM (54.4%) and IgG (86.1%) antibodies was ascertained in rabbits with neurological symptoms ( n = 79, group I). In rabbits with renal disorders ( n = 47, group II) 36.2% animals were specific IgM and 80.9% IgG positive. Out of 9 rabbits with ocular disorders (group III), 44.4% were positive for anti- E. cuniculi IgM and 77.8% for IgG antibodies. In rabbits with multiple signs (neurological and renal or ocular, n = 16, group IV), 43.8% animals were specific IgM and 68.8% IgG positive. Out of 287 rabbits with other disease (group V), 26.5% were positive for anti- E. cuniculi IgM and 64.1% for IgG antibodies. However, the high presence of IgM (24.2%) and IgG (51.6%) antibodies was detected in clinically healthy rabbits ( n = 62, group VI). Toxoplasma gondii infection should be considered as a differential diagnosis for neurological and ocular disorders in rabbits. Using ELISA, 19.2% from all rabbits were positive for specific anti- T. gondii IgG. The highest seropositivity was detected in group III (44.4%). Simultaneous testing of IgM and IgG specific antibodies give an indication of the infection status. Presence of IgM antibodies is indicative for active infection with requirement to institute proper antimicrosporidial therapy. As active infection was detected in considerably high numbers of rabbits with clinical signs that are not usually associated with E. cuniculi, and even in asymptomatic rabbits, detection of both isotypes of specific antibodies should be a routine part of a health check in rabbits.