Brachyspira aalborgi is a species of bacteria, one of the causative agents of intestinal spirochetosis.[1][2] Its cells are anaerobic, sigmoidal with tapered ends, 2 to 6 μm long. Four flagella are inserted at each end of the cells. The maximal cell width is about 0.2 μm. The type strain is 513A (NCTC 11492).[3]