Molecular characterization of a hepatitis E virus isolate from Namibia

Area of Science:

• Virology
• Molecular Biology
• Epidemiology

Background:

• Hepatitis E virus (HEV) is a significant cause of acute viral hepatitis globally, particularly in developing nations.
• HEV has been detected in various African countries through virus detection and antibody presence, indicating widespread circulation.
• A 1983 jaundice outbreak in Namibia yielded HEV isolates, preserved for later etiological determination.

Purpose of the Study:

• To genetically characterize Hepatitis E virus (HEV) isolates from a 1983 Namibia outbreak.
• To compare the genetic sequences of Namibian HEV isolates with other global and African strains.
• To understand the phylogenetic relationship and historical transmission patterns of HEV in Africa.

Main Methods:

• HEV genomic sequences were detected using antigen-capture reverse transcriptase polymerase chain reaction (RT-PCR).
• Nucleotide sequencing of the 3' end of the capsid gene (ORF-2) and ORF-3 was performed on one isolate.
• Phylogenetic analysis was conducted to compare the Namibian HEV strain with reference strains.

Main Results:

• The Namibian HEV isolate (HEV 83-Namibia) showed 86% nucleotide identity with the Burma strain and up to 96% with other African strains.
• Amino acid identity between HEV 83-Namibia and other African or Burma strains reached 99%.
• Phylogenetic analysis revealed that HEV 83-Namibia is closely related to other African HEV isolates, distinct from Burmese, Mexican, and Chinese strains.

Conclusions:

• The HEV strain from the 1983 Namibia outbreak is genetically linked to HEV strains found in more recent transmissions across northern and sub-Saharan Africa.
• This suggests a persistent circulation and establishment of this specific HEV subgenotype throughout the African continent.
• The findings highlight the importance of molecular epidemiology in tracing the historical spread and evolution of viral pathogens like HEV in Africa.