Abstract

During a study of mortality in raptors, sporulated coccidian oocysts were noted in the lamina propria of the small intestine of 47 of 86 (54.7%) Cooper’s hawks examined. No pathology was associated with the presence of these oocysts. On subsequent examination of fresh feces from seven birds, sporocysts with mean dimensions of 13.4×8.9 µm, a shape index of 1.3 (1.4–1.6), and diffuse residuum were observed. These sporocysts were morphologically similar to Frenkelia and Sarcocystis spp. To determine the phylogenetic relationship of this Frenkelia sp. to other Frenkelia and Sarcocystis spp., a fragment (∼700-bp) of the 18S rRNA gene was amplified from three samples and sequenced. This Frenkelia sp. was most closely related to F. buteonis (S. microti) and F. glareoli (S. glareoli), both of which use hawks in the genus Buteo as definitive hosts and various rodents as intermediate hosts.