EDITOR, — A longstanding hypothesis based on indirect and epidemiological evidence proposes that motor neurone disease is a late consequence of subclinical infection with poliovirus. C J Woodall and colleagues provide supportive evidence for this “enterovirus hypothesis,” reporting the finding of conserved enterovirus sequences in the spinal cords of nine of 13 patients with motor neurone disease when they used conventional polymerase chain reaction and hybridisation; they conclude that these sequences were related to Coxsackie B virus rather than poliovirus.1 The enterovirus hypothesis has also been proposed for idiopathic inflammatory myopathy, and Behan and Behan, from the same group as Woodall and colleagues, have reported finding enterovirus in 56% …