Detection of hepatitis A virus RNA from children patients with acute and fulminant hepatitis of unknown etiology in Vietnam: Genomic characterization of Vietnamese HAV strain

Abstract

Background: Although it is thought that Vietnam is a high endemic region of hepatitis A virus (HAV) infection, there is no report on genomic characterization of HAV spread in Vietnam. The purpose of the present paper was therefore to identify various virus infections from 33 children with acute or fulminant hepatitis of unknown etiology admitted to Children's Hospital No.1 in Ho Chi Minh City, Vietnam.

Methods: Anti-HAV IgM and IgG were assayed by ELISA. Viral RNA and DNA were determined by PCR method. HAV genes isolated by PCR were sequenced and characterized by phylogenetic analysis.

Results: Anti-HAV IgM was detected in 18 of 26 acute hepatitis (69.2%) and one of seven (14.3%) fulminant hepatitis patients. Furthermore, HAV-RNA in serum was identified in five of 26 acute (19.2%) and two of seven (28.6%) fulminant hepatitis patients, respectively, on nested reverse transcription-polymerase chain reaction. Among the seven HAV-RNA-positive patients tested, two (28.6%) were negative for anti-HAV IgM. We also obtained seven isolates containing the HAV genome with the viral protein 1 (VP1) region sequence. All Vietnamese HAV isolates formed a cluster and belonged to genotype IA according to phylogenetic analysis based on the short sequences of VP1-2A junction region.

Conclusion: HAV is an important agent with regard to fulminant hepatitis among children in Vietnam. To the authors' knowledge this is the first report on Vietnamese HAV strain confirmed on sequencing.