Isospora albicollis (Apicomplexa: Eimeriidae) in thrushes Turdus spp. (Passeriformes: Turdidae), in southeastern Brazil

Abstract The aim of the present study was to report and describe Isospora albicollis Lainson and Shaw, 1989 parasitizing a white-necked thrush Turdus albicollis Vieillot, 1818 and a pale-breasted thrush Turdus leucomelas Vieillot, 1818 in two different localities: the Itatiaia National Park and Cacaria, in southeastern Brazil. The oocysts identified were ovoidal, 24.4 × 19.7 μm, with a smooth, bilayered wall, around 1.4 μm thick. Oocyst residuum was absent, but a micropyle and a polar granule were present. The sporocysts were ellipsoidal, 15.4 × 10.1 μm. The Stieda body was knob-like to rounded and the sub-Stieda body was prominent and wide. Sporocyst residuum was present, usually as a cluster of granules that appear to be membrane-bounded. The sporozoites were vermiform with one posterior refractile body and a centrally located nucleus. Besides recording the new host T. leucomelas, the identification of I. albicollis in the Itatiaia National Park and Cacaria, in southeastern Brazil, provide records of new localities for its parasitism, and reveals the wide distribution and dispersion of this coccidium in Brazil.