No Viruses in Muscles of Patients with Amyotrophic Lateral Sclerosis

To the Editor: In the past we examined tissues from many autopsies of patients with amyotrophic lateral sclerosis (ALS) for evidence of a viral origin of the disease. 1 The tissues were examined with various techniques, including electron microscopy and several culture methods. We focused on tissues of the central nervous system and studied muscle tissues from only a few patients. Our only positive finding was the detection of numerous crystalline arrays of dense virus-like particles, which were 20 to 24 nm in diameter and resembled picornaviruses, in the muscle tissue of one patient. 2 Because of this finding, as well as . . . No extract is available for articles shorter than 400 words.