Further evidence of cellular changes associated with non-A, non-B hepatitis.

Two distinct types of ultrastructural changes were found in the hepatocytes of chimpanzees infected with two forms of non-A, non-B hepatitis. In the type of infection that was of long incubation, there was a marked cytoplasmic derangement of the endoplasmic reticulum, with the formation of tubules, but no pathological changes in the nuclei. In the short-incubation type of non-A, non-B hepatitis, induced experimentally in a chimpanzee that had recovered from the long-incubation type of infection, nuclear alterations were found together with the presence of aggregates of particles measuring 15--27 nm in diameter. Cytoplasmic tubules were not seen in this type of non-A, non-B infection.