Chronic Myopathy Associated with Coxsackievirus Type A9

Abstract

Virus-like crystalline structures in human skeletal muscles have been observed by many electron microscopists, but no viruses have been isolated and identified in such cases. An 11-year-old girl who had had muscular weakness and physical retardation since early infancy died of pneumonia due to atrophy of diaphragmatic and intercostal muscles. Electron microscopy of these muscles revealed a heavy infiltration of picornavirus-like particles that measured 19 to 23 nm in diameter. Subsequent inoculation of primary human-amnion cells with a sonic-treated suspension of the patient's diaphragmatic muscle induced an enterovirus-like cytopathic effect. The isolate was identified with use of Lim-Benyesh-Melnick enterovirus typing serum pools as coxsackievirus Type A9. This viral isolation supports the belief that the organized electron-dense particles in human muscle are indeed virions. (N Engl J Med 292:608–611, 1975)