Reovirus-like agent in acute epidemic gastroenteritis in Japanese infants: fecal shedding and serologic response.

The reovirus-like agent, sometimes referred to as duovirus or rotavirus, was visualized by electron microscopy in stool extracts from Japanese infants and young children with acute epidemic gastroenteritis. The virus particles measured 70 nm in diameter and had double-shelled capsids. One hundred ten (89%) of 124 patients with the gastroenteritis had such virus particles in stools obtained during the acute phase. The virus particles were excreted in the stools usually during the first eight days of illness. Agglutination of virus particles by antibody present in convalescent-phase sera was demonstrated by immune electron microscopy. Complement-fixing antibody was detected as early as day 3 of illness, and antibody titers peaked during the second and third weeks of the disease. The antibody appearing in the acute and early convalescent phases was sensitive to 2-mercaptoethanol. Antibody resistant to 2-mercaptoethanol was produced approximately 10 days after the onset of the symptoms. The serologic evidence suggests that a primary infection with the reovirus-like agent was responsible for the clinical attack of acute gastroenteritis.