Abstract
27 of 57 boys and 1 of 37 staffs developed acute hepatitis, type A from July, 1976 to Feburary, 1977 at an orphanage in Oita city.
The diagnosis of acute hepatitis, type A was confirmed by the demonstration of hepatitis-A virus in a stool specimen of one patient by immune-electron microscopy (I.E.M.)and rises in titres of serum hepatitis A (HA) antibody which were determined by I.E.M. and radioimmuno assay (HAVAB, Dainabott).
Epidemiological investigation incriminated contaminated bath water.
Abortive infection in this outbreak of acute hepatitis, type A was found at 21 of 28 boys (75%), who didn't develope acute hepatitis. In 7 of these 28 boys (25%), serum HA antibody at the first time was negative and 5 month later, the antibody become positive.
In other 14 boys, rises in titres of serum HA antibody were demonstrated.
It was interesting that the rate of abortive infection in this outbreak was significantly higher than that in an outbreak at Kiyama.
Clinical course in 7 patients with HBsAg carrier state is significantly longer than that in HBsAg negative group.
