AN EPIDEMIC OUTBREAK OF HEPATITIS-E IN YANGON OF MYANMAR - ANTIBODY-ASSAY AND ANIMAL TRANSMISSION OF THE VIRUS

An epidemic outbreak of hepatitis E occurred in an army recruit camp o f Yangon, Myanmar, in October 1989. One hundred and eleven patients am ong 600 residents were hospitalized. As high as 83.7% of these patient s were positive for the acute phase antibody against hepatitis E virus by an enzyme-linked immunosorbent assay developed in our laboratory. Also, 30.6% of 49 symptom-free residents examined were positive for th e antibody. We prepared a stool extract from six patients and inoculat ed it into 10 rhesus monkeys for a series of three subpassages. All of them developed acute biochemical hepatitis along with an elevation of antibody levels. A rechallenge with viruses of the present outbreak f ailed to provoke hepatitis in two monkeys that had previously recovere d from acute hepatitis caused by an isolate of sporadic hepatitis E of the same area. Similarly, the rechallenge of the sporadic strain did not induce hepatitis in two monkeys that had been previously infected with the epidemic virus. These data suggested that the subjects would obtain neutralizing antibodies against the hepatitis E virus once infe cted, and many adult inhabitants of the endemic area had no protective antibodies and were still susceptible to hepatitis E infection.