Sarcocystis calchasi-associated neurologic disease in a domestic pigeon in North America

Tissue cysts of a protozoan parasite were present in the skeletal muscle of a domestic pigeon (Columba livia f. domestica) with neurologic disease in Minnesota, USA. The animal had a severe granulomatous meningoencephalitis. The cysts were slender, up to 1mm long and up to 0.03mm in diameter. The cysts had a smooth wall without projections. Size and wall morphology were compatible with Sarcocystis calchasi. Polymerase chain reaction using S. calchasi-specific primers resulted in a specific amplicon from the skeletal muscle but not from the brain. Sequencing of the highly variable genomic regions ITS1 and D2 revealed 100% nucleic acid identity with the German strain of S. calchasi. Sarcocystis calchasi is the cause of an emerging lethal disease in pigeons in Germany. This is the first description of the parasite outside of Germany.