Peripheral nervous system involvement in experimental tuberculosis.

Following intravenous injection of mycobacteria in the mouse the bacilli are regularly found in the peripheral nervous system after the 5th day. The peripheral nerves and autonomic ganglia are involved at the level of the perineural cells and the sheath of Schwann. When the organisms are of low virulence (BCG, Mycobacterium intracellulare) the development of the nodules is limited. In the case of a virulent strain (Ravenel) extensive granulomas are found but epitheloid cells, always found in other organs, are constantly absent. In animals previously immunized, the bacilli seem to implant themselves as in the controls, but multiply more slowly; the nodules are more infrequent and the lymphoid infiltration appears earlier with the multiplication of interstitial cells.