Abstract
Between 1982 and 1987 sera from 4952 New Zealand White rabbits (Oryctolagus cuniculus) obtained from a single commercial supplier were tested for the presence of antibodies to Encephalitozoon cuniculi. A commercially available carbon immunoassay test kit was used. Initially 32·9% of the rabbits were seropositive with the number progressively decreasing to 2·3% by 1987. The reason for the significant decline in the incidence of infection was most likely due to a selection process for breeding stock instituted by the supplier based upon productivity, posture and weight of each animal.