Encephalitozoon hellem infection in aviary passerine and psittacine birds in Spain

A European goldfinch (Carduelis carduelis), a canary (Serinus canaria), and a lovebird (Agapornis roseicollis) captive-bred at three different private aviaries in Spain were submitted for necropsy with a history of weakness and ruffled feathers, weight loss associated with glossitis, and respiratory disease, respectively. Microscopically, enterocytes in the jejunum and ileum contained colonies of gram- and Stamp-positive, oval to elliptical microorganisms within parasitophorous vacuoles in the apical cytoplasm. Nested PCR using MSP primers that target microsporidian RNA genes produced amplicons of expected size for Encephalitozoon species, and analysis of forward and reverse DNA sequences confirmed the presence of Encephalitozoon hellem in all cases. The main cause of death of all three birds consisted of concurrent infections. However, intestinal encephalitozoonosis may have contributed to exacerbated catabolism. Encephalitozoonosis (or microsporidiosis) has been rarely described in passerine birds.