Balantidium sp. in ostriches (Struthio camelus L., 1758) in the State of Rio de Janeiro, Brazil.

The aim of this work was report for the first time the occurrence of Balantidium sp. in ostriches reared in Rio de Janeiro state, Brazil. Feces samples from 82 ostriches were examined by the Ziehl-Neelsen technique and morphometric analyses were made of the cysts. The data were compared by a simple linear regression analysis. The cysts found ranged in size from 60.39 by 34.62 mm and 59.13 by 33.92 m in diameters. The spherical shape was confirmed by observing the shape index of 1.05 and r = 0.9630, which suggested there were cysts of different sizes with similar shapes. In spite of polymorphism, cysts measurements were uniform in their distribution, evidencing the possibility of a single species (R2 = 0.9274). The cysts were morphologically indistinguishable from the Balantidium sp. cysts already reported in ostrich feces or B. coli. This is the first report of parasitism by Balantidium sp. in ostriches in Brazil. In spite of the high Balantidium sp. frequency, no clinical sign was observed.