A redescription of Cryptosporidium galli Pavlasek, 1999 (Apicomplexa: Cryptosporidiidae) from birds.

Cryptosporidium galli Pavlasek, 1999, described from the feces of birds, is redescribed with additional molecular and biological data. Oocysts are ellipsoidal, are passed fully sporulated, lack sporocysts, and measure 8.25 x 6.3 microm (range 8.0-8.5 x 6.2-6.4 microm) with a length-width ratio of 1.30 (n = 50). Oocysts are structurally similar to those of Cryptosporidium baileyi described from chickens, but in addition to being considerably larger than oocysts of C. baileyi, these oocysts infect the proventriculus in a variety of birds and not the respiratory tract. Oocysts were successfully transmitted from chickens to chickens, and morphologically similar oocysts also were observed in a variety of exotic and wild birds (Order Passeriformes, Phasianidae, Fringillidae, and Icteridae). Molecular and phylogenetic analyses at the 18S rRNA, HSP70, and actin gene loci demonstrate that this species is genetically distinct from all known species and genotypes of Cryptosporidium and, thus, was named C. galli.