Currently circulating genotypes of hepatitis E virus in India, 2014-2018

Hepatitis E virus (HEV) is an emerging pathogen causing acute viral hepatitis worldwide. Clinical manifestations often occur in young adults with an increased mortality rate among pregnant women. HEV genotypes 1 and 4 are mainly reported among humans and swines, respectively.

The aim was to study the currently circulating genotypes of HEV in India.

A retrospective cross-sectional study was carried out at Manipal Institute of Virology to know the circulating genotypes of hepatitis E, spanning over 5 years from August 2014 to September 2018. The serum samples screened serologically positive and confirmed positive for active infection by real-time reverse transcriptase-polymerase chain reaction (PCR) (Real Star^® HEV RT-PCR Kit 2.0, Altona Diagnostics, GmbH, Hamburg, Germany) were further subjected to nested conventional PCR targeting the RdRp gene of non-structural ORF1 region. The purified PCR product was sequenced in BigDye Terminator v3.1 Cycle Sequencing Kit (Life Technologies, Thermo Fisher Scientific, USA). The chromatograms obtained by sequencing were analysed using Sequencher 5.4.6, and HEV FASTA sequences were compared with reference sequences for HEV in GenBank Nucleotide Blast.

During the study period, there were 317 cases of laboratory-confirmed cases of acute viral hepatitis comprising 202, 70, 43 and 2 cases of hepatitis A, E, B and C, respectively. Serum samples of 70 acute hepatitis cases were positive for anti-hepatitis E IgM. According to the clinical case classification, there were 66 cases of acute viral hepatitis and four cases of fulminant hepatic liver failure. The mean age of the patients was 30.3 years (standard deviation = 12.5). The samples from various parts of India were genotyped as 1a.

The HEV genotypes 1a was observed to be the currently circulating strain in the regions studied.