Atoxoplasma serini usually infects passerines two to nine months old 1 . Reported clinical signs include diarrhea, decreased appetite, inactivity, weight loss, ruffled feathers, and nonspecific neurological signs. In some cases, liver enlargement can be appreciated through the abdominal skin of affected birds 1 .
Clinical signs are, however, frequently absent or nonspecific.
We attributed the acute respiratory distress seen in this bird to the onset of shock following rapid reproduction of A. serini in the reticulo-endothelial system, and the subsequent release of inflammatory mediators. A. serini is a great deal more pathogenic than the more common coccidian that affects canaries, Isospora canaria . In addition, infected birds will continue to shed oocysts for up to eight months, even when kept in suspended wire cages to prevent fecal-oral reinfection 2 . The biological basis for the extreme pathogenicity of A. serini , as compared to I. canaria , awaits investigation. No drug that successfully eliminates Atoxoplasma infections has been identified 1 .