This study aimed to research the long-term shedding of Isospora spp. oocysts in several species of passerines naturally infected and kept in captivity. Two hundred and eighty-nine fecal samples were collected from two flocks with previous diagnosis of isosporosis, in which several adult passerine species were raised. Samples were collected individually, monthly, for 13 months, purified in Sheather's sugar solution and examined using microscopy. Of the 289 samples, 159 (55.02%) were positive for Isospora spp. oocysts and 130 (44.98%) were negative. Most of the birds analyzed shed oocysts in small quantity (score 1), intermittently and for a long period. Despite the occurrence of Isospora infection, the birds that were analysed showed no clinical isosporosis. The results of this research provide data for the control of isosporosis in passerines raised in captivity. The decisions about performing prophylactic or curative treatment, as well as decisions related to hygiene and sanitary measures must take into account not only the presence of the parasite in feces, but also the intensity of oocysts shedding, as well as evaluation of sanitary and nutritional management and the presence of clinical signs and/or mortality.
birds; fecal samples; Isospora spp.; oocysts