Acute myopathy associated with influenza A/Texas/1/77 infection. Isolation of virus from a muscle biopsy specimen.

Influenza A/Texas/1/77 was isolated from a muscle biopsy specimen from a patient with muscle weakness and increased serum creatine phosphokinase level. The patient was seen during an outbreak of influenza A/Texas/1/77 that was associated with myopathy. Isolation of this virus from this patient's muscle specimen suggests that the myopathy associated with influenza may be due to direct infection of skeletal muscle.