Sporadic hepatitis E infection in southern China

China is a hepatitis E endemic region. For many years, the Burmese-like hepatitis E virus (HEV) strain was considered to be responsible for hepatitis E in China. However, in 1993, a novel sporadic divergent HEV isolate (G-9 and G-20) was found in two patients with hepatitis E in Guangzhou, southern China. Subsequently, the Guangzhou divergent (GZD) isolate was also found in other patients in Guangzhou and even in Taiwan. The Taiwan patients had a history of traveling to China before onset of the disease. These findings indicate that the GZD isolate is responsible for some of these sporadic HEV infections.{09}The discovery demonstrates the presence of significantly divergent variant and has led to the identification of a number of additional isolates from many other regions.; To investigate more extensively the GZD isolate and its role in sporadic HEV infection in southern China, a relevant fecal strain (93G strain) of the G-9 isolate was isolated by A549 cell culture and identified immunologically and molecular biologically in this study. In the isolation and identification of the 93G strain in cell culture, cytopathic effects (CPE), morphology and morphogenesis of the 93G strain were observed by light microscope (LM), electron microscopy (EM) and immune electron microscopy (IEM) respectively. The results showed that 93G virus could be propagated in the A549 cells. The infected cells became round and lysed gradually until all the cells in the monolayer were destroyed. Through EM observation, progressive development of local vesicles, virions accumulation in crystalline arrays and viroplasmic focus were seen in cytoplasm of infected cells. Replication and assembly of the newly generated viruses were closely associated with CPE. The viral particles were about 29∼32 inn in diameter and can be aggregated by a specific antibody to HEV Chinese Xinjiang strain (87A) as observed by IEM or neutralized by serum from the patient with hepatitis E and were similar morphologically to HEV from other sources. 93G viral RNA was amplified by reverse transcriptase and polymerase chain reaction (RT-PCR) and showed high homology (93%) with that of the G-9 isolate but was also as divergent from the Burmese-like isolates, Mexican isolate and US isolates, as was G-9. The result suggests the A549 cell line is a reliable cell culture system for HEV replication. The establishment of this reliable system is very important for further study of the virus. (Abstract shortened by UMI.)...