Abstract
Sarcocystis spp. cause pigeon protozoan encephalitis, a neuronal disease. A female pigeon exhibiting torticollis had a necrotic area in the cerebral hemisphere surrounded by lesions with perivascular cuffing, gliosis, granulomatous foci, and meningitis. Non-necrotic lesions were also observed in the brainstem. Intact and degenerative schizonts were observed within the neuropils and neurons in the lesions. Deoxyribonucleic acid (DNA) was extracted from paraffin-embedded brain tissues and genetically analyzed after gel electrophoresis to determine Sarcocystis spp. using specific primer sets for 28S ribosomal ribonucleic acid and internal transcribed spacer region-1. DNA sequencing confirmed a significant homology with S. calchasi. This is the first report of meningoencephalitis with malacia caused by S. calchasi in a rock pigeon in Japan.