Mixed infection with hepatitis E virus (HEV) in patients with chronic hepatitis B virus (HBV) infection is frequent. HEV mixed infection often leads to activation of hepatic pathological changes and worsens the inflammatory activity. However, it is not known clearly how these two types of virus influence each other in human body. Intensive investigation has revealed that HEV mixed infection inhibits HBV replication. We have just encountered a relative rare case. The patient who was a HBV carrier and was infected by HEV. Before he was infected by the HEV, the measurement of his HBV DNA fixed quantity examination on fluorescence was <103 copies/ml; his routine biochemistry was normal; and his anti HEV-IgM and anti-HEV-IgG appeared to be negative reaction. After he was infected by HEV, his routine biochemistry increased, and the measurement of his HBV DNA fixed quantity examination on fluorescence was 8.51 × 105 copies/ml. It indicated that the replication of HBV was activated after the patient infected HEV. Finally, he was dead. This case revealed that HEV mixed infection may activate the replication of HBV, not inhibit HBV replication, and demonstrated the needs for further studies about the mechanism of the interaction of the two viruses.
 Cheng, S.-H., Mai, L., Zhu, F.-Q., Pan, X.-F., Sun, H.-X., Cao, H., Shu, X., Ke, W.-M., Li, G. and Xu, Q.-H. (2013) Influence of Chronic HBV Infection on Superimposed Acute Hepatitis E. World Journal of Gastroenterology, 19, 5904-5909. http://dx.doi.org/10.3748/wjg.v19.i35.5904
 Zhao, J., Wang, S., Zhang, T., Liu, P., Zhou, G.D., Sun, Y.L. and Yin, T.Y. (2001) Pathological and Virological Studies of the Liver Tissues from the Patients with Sporadic Hepatitis E. Chinese Journal of Experimental and Clinical Virology, 15, 205-207.
 Guan, Q.-F., Zhang, Y.-X. and Sun, H.-R. (2000) Clinical Analysis and Effect on Replication of HBV in Chronic Hepatitis B with HEV Superinfection. Journal of Xinjiang Medical University, 23, 234-235.
 Kumar, A., Aggarwal, R., Naik, S.R., Saraswat, V., Ghoshal, U.C. and Naik, S. (2004) Hepatitis E Virus Is Responsible for Decompensation of Chronic Liver Disease in an Endemic Region. Indian Journal of Gastroenterology, 23, 45- 46.
 Ramachandran, J., Eapen, C.E., Kang, G., Abraham, P., Hubert, D.D., Kurian, G., Hephzibah, J., Mukhopadhya, A. and Chandy, G.M. (2004) Hepatitis E Superinfection Produces Severe Decom-pensation in Patients with Chronic Liver Disease. Journal of Gastroenterology and Hepatology, 19, 134-138. http://dx.doi.org/10.1111/j.1440-1746.2004.03188.x
 Hamid, S.S., Atiq, M., Shehzad, F., Yasmeen, A., Nissa, T., Salam, A., Siddiqui, A. and Jafri, W. (2002) Hepatitis E Virus Superinfection in Patients with Chronic Liver Disease. Hepatology, 36, 474-478. http://dx.doi.org/10.1053/jhep.2002.34856
 Chu, C.M., Yeh, C.T. and Liaw, Y.F. (1999) Viral Superinfection in Previously Unrecognized Chronic Carriers of Hepatitis B Virus with Superimposed Acute Fulminant versus Nonful-minant Hepatitis. Journal of Clinical Microbiology, 37, 235-237.
 Coursaget, P., Buisson, Y., N’Gawara, M.N., Van Cuyck-Gandre, H. and Roue, R. (1998) Role of Hepatitis E Virus in Sporadic Cases of Acute and Fulminant Hepatitis in an Endemic Area (Chad). American Journal of Tropical Medicine and Hygiene, 58, 330-334.
 Chow, W.C., Lee, A.S., Lim, G.K., Cheong, W.K., Chong, R., Tan, C.K., Yap, C.K., Oon, C.J. and Ng, H.S. (1997) Acute Viral Hepatitis E: Clinical and Serologic Studies in Singapore. Journal of Clinical Gastroenterology, 24, 235- 238. http://dx.doi.org/10.1097/00004836-199706000-00011
 Tan, D., Im, S.W., Yao, J.L. and Ng, M.H. (1995) Acute Sporadic Hepatitis E Virus Infection in Southern China. Journal of Hepatology, 23, 239-2345. http://dx.doi.org/10.1016/S0168-8278(95)80001-8
 Tsai, J.F., Jeng, J.E., Chang, W.Y., Lin, Z.Y. and Tsai, J.H. (1994) Antibodies to Hepatitis E Virus among Chinese Patients with Acute Hepatitis in Taiwan. Journal of Medical Virology, 43, 341-344. http://dx.doi.org/10.1002/jmv.1890430405