Effects of viral and Mycoplasma infections on the ultrastructure of human skeletal muscle.

The ultrastructure of skeletal muscle from 10 patients confined to bed for about one week with different viral or mycoplasma infections has been studied in the acute phase of the disease and 1 1/2 and 4 months later. Focal deviations from normal ultrastructure were found in the first muscle biopsy. The changes were less pronounced after 1 1/2 months and absent after 4 months. In 5 healthy controls, confined to bed for one week, normal ultrastructure was found on corresponding occasions.