A High Proportion of Encephalitozoon cuniculi Antibody-Positive Domestic Rabbits Identified in Northern Portugal:...

Encephalitozoon cuniculi is a globally distributed microsporidian of veterinary and public health relevance, particularly due to its zoonotic potential and high prevalence in domestic rabbits (Oryctolagus cuniculus). This study aimed to estimate the presence of anti-E. cuniculi antibodies in pet rabbits from the Porto district, Portugal, using an indirect enzyme-linked immunosorbent assay (ELISA). Blood samples were collected from 54 domestic rabbits during routine veterinary appointments and hospitalisation between September 2024 and January 2025. Plasma samples were analysed for anti-E. cuniculi antibodies. Thirty-four rabbits (63%) were seropositive, indicating substantial exposure within the sampled population. This prevalence is consistent with reports from other European countries and may indicate E. cuniculi is endemic among pet rabbits in Portugal. Given the zoonotic nature of this pathogen, these findings reinforce the need for surveillance strategies integrating animal and public health perspectives.