Seroprevalence of Encephalitozoon cuniculi Infection in Pet Rabbits in Brazil

Encephalitozoon cuniculi is an obligate intracellular parasite responsible for encephalitozoonosis, primarily an opportunistic infection of rabbits but also other animals, including humans, which affects the nervous system, kidney, liver, and eyes. This article reports the results of a research investigation that examined the seroepidemiological data from rabbits diagnosed with encephalitozoonosis in Brazil. A total of 186 pet rabbits (Oryctolagus cuniculus) either with subclinical infection or presenting with ophthalmic or neurological signs suggestive of encephalitozoonosis were included in the study. Using enzyme-linked immunosorbent assay, antibodies to E. cuniculi were detected in 81.7% of the animals. Serological status did not correlate with place of birth, age, gender, breed, or fur color of the animals. Of the 152 seropositive rabbits, 89% (136 rabbits) were subclinical, supporting their role as E. cuniculi reservoirs. Of the 16 seropositive animals with clinical signs, 62.5% (5 rabbits) showed ophthalmic signs, 60% (6 rabbits) presented with neurological signs, and 62.5% (5 rabbits) had a combination of ophthalmic and neurologic signs. These results indicate a high prevalence of E. cuniculi infection in pet rabbits being cared for in Brazil, thus highlighting the importance of improving diagnostic and control measures. Further research studies are required to determine if the parasite strain is a significant factor for zoonotic transmission.