Hepatitis E, which is also primarily transmitted through the gastrointestinal tract, is more severe and has a higher mortality rate than hepatitis A. How long do we need to quarantine patients with these infectious diseases? The study of hepatitis E, one of the major national research projects, has reached a conclusion. Professor Zhuang Hui, head of the group, recently revealed that the fecal detoxification of hepatitis E patients mainly occurs in the early acute phase of the disease, and the isolation period should be set at 4 weeks after the disease. The Department of Pathogenic Biology of Peking University Medical School tested the stool and serum of 302 patients with acute hepatitis E in 17 cities in China to observe their fecal detoxification pattern. The results showed that the detection rate of positive hepatitis E virus RNA in stool and serum of patients was above 70% within 1 week of onset; only individual patients had hepatitis E virus RNA detected in serum at the 4th week after onset, but the detection of hepatitis E virus RNA in stool failed to be positive. In addition, the group also conducted animal experiments. As a result, the detection rate results of animal experiments were consistent with those of hepatitis E patients. The researchers analyzed that among the tested hepatitis E patients, fecal detoxification and viremia mainly occurred within 4 weeks of onset, from which it can be determined that the infectiousness of the patients mainly occurred during this period. Therefore, the quarantine period for hepatitis E patients should be set at 4 weeks after illness.