ALS

Polioviruses (and other enteroviruses) have long been considered a possible cause of ALS because these viruses and ALS share the same pathologic target, the motor neuron. 1 In addition, an increased frequency of ALS has been reported to occur in patients with previous poliomyelitis. 2However, these epidemiological reports remain controversial 3 and may relate to earlier confusion with the syndrome of late weakness and atrophy that occurs after poliomyelitis, 4 post-polio syndrome. Since it is now recognized that persistent poliovirus and other enterovirus infections occur in animals, immunodeficient humans, and cell culture systems, it remains important to examine viruses as causative agents of ALS. 1 Over the last 30 years, there have been many attempts to find viruses in ALS tissues. These studies have included antibody assays, standard viral isolation techniques, and electron microscopy for viral particles, and all have been uniformly negative. 5 …