Sequence Comparison of the Capsid Region of Hepatitis E Viruses Isolated from Myanmar and China

Abstract

Hepatitis E viruses (HEVs) were isolated during epidemics, one from Myanmar (formerly called Burma) and one from China and were partially sequenced. Another HEV Myanmar strain from sporadic hepatitis was previously sequenced by us. A cDNA seq uence comparison was performed among them in the 3'-terminal region, approximately 750-base long. This region contained at least two immunological epitopes and was considered to correspond to the structural protein. The nucleotide sequence identity was 97.2% between the two Myanmar strains and 93.3 and 92.5% between the two Myanmar and the China strain. The deduced amino acid sequence identity ranged from 98.4 to 100.0% among the three strains. Thus this segment was well conserved on the amino acid level among the different strains isolated from these two Asian countries, although the China strain diverged more from the Myanmar strains on the nucleotide sequence level. This data may provide important information for the development of a vaccine and for identification of the virological link between different geographical locations.Hepatitis E is prevalent in many developing countries, predominantly in tropical and subtropical areas. In these countries it provokes epidemic outbreaks frequently involving more than several thousand patients (8) and sporadic hepatitis in the periods between epidemics. Hepatitis E may not be endemic to the industrialized countries; however, it does occur as "imported hepatitis" via immigrants, tourists or workers (6, 10). A vaccination must be developed to eradicate hepatitis E from the world.The HEV has a single-stranded, plus-sense RNA genome, approximately 8.6-kilobase long (14). Viral full-length cDNA was sequenced by Reyes and his colleagues (17), and by us as well (1). Their and our viruses originated from hepatitis E from Yangon (formerly called Rangoon) of Myanmar. In other cases, we partially sequenced strains isolated from epidemic hepatitis E in Yangon (Uchida et al, submitted for publication) and in China (3).

Hepatitis E virus

“…HEV clones from several isolates have been developed within the last few years [15,24,74,76,77,152,156,157]. In these studies, fused ORF2-GFP expression has been used to monitor the replication potential of the HEV clone.…”

II. Existing variations on the gene structure of hepatitis E virus strains from some regions of China

“…Since the molecular cloning and sequencing of HEV were described [Reyes et al, 1990;Tam et al, 19911, several genomic analyses of the HEV strains obtained from different geographic areas have been reported [Tsarev et al, 1992;Huang et al, 19921. Almost all of the HEV used for sequencing was obtained from the bile of experimentally infected animals or the stools of patients [Aye et al, 1992;Bi et al, 19931. In this study, a strain of the cultured HEV (87A strain) which has not been reported up to now was sequenced.…”

Seroprevalence of Hepatitis E Virus Infection, Rural Southern People’s Republic of China

“…While viruses of genotypes 1 and 2 are isolated exclusively from humans, those from genotypes 3 and 4 have also been isolated from swine and other animals ( 7 ). Genotype 1 strains are mainly distributed in Asia and the Middle East ( 8 , 9 ), where they frequently cause waterborne outbreaks of hepatitis ( 10 , 11 ). Genotype 2 virus was first detected in Mexico ( 12 ).…”