Molecular characterization of hepatitis A virus isolated from patients with acute hepatitis infections in Duhok city, Iraq

Background : Hepatitis A virus (HAV) is prevalent worldwide and is among the leading causes of acute viral hepatitis in Iraq. This study aimed to determine the molecular characteristics and predominant circulating genotype of the hepatitis A virus in Duhok, Iraq, to determine its genetic relatedness to reference viruses. Methods : Blood samples were obtained from 171 patients who had acute viral hepatitis from August 2020 to November 2021. Serum samples were tested for (IgM) anti-HAV antibodies via ELISA. Seropositive samples were subjected to conventional nested reverse transcription‒polymerase chain reaction (RT‒PCR) for the VP1/2A region with specific primers, sequenced and submitted to GenBank. Sequence identity and phylogenetic relatedness were analyzed for selected HAVs. Results : Hepatitis A virus-specific IgM antibodies were detected in 37 out of 171 patients (21.6%). All 37 positive samples were positive according to RT‒PCR. The sequences of 12 positive samples were submitted to GenBank, and the circulating genotype was found to be IB. High sequence identity was observed with the selected HAVs. Nucleotide substitutions were found, but only one sample had a substitution of lysine with arginine at position 788 of the VP1-2A gene compared with the reference strain. Conclusion : Hepatitis A is a common type of acute viral hepatitis caused by IB as a circulating genotype in this region. One sample presented a substitution of lysine (K) with arginine (R) in the amino acid sequence of the VP1-2A gene, which may require further analysis to determine whether the effectiveness of the vaccine is altered.