In a comprehensive new retrospective study, GenPath Africa colleagues Derek Tshiabuila, Tongai G. Maponga, Eduan Wilkinson, Cheryl Baxter, and Tulio de Oliveira from Stellenbosch University investigated the evolutionary mechanisms of the Hepatitis B virus (HBV). Their research provides a detailed map of how the virus exchanges genetic material, offering critical insights into the global diversity and long-term evolution of this significant public health threat.

What is this publication about?

Researchers analysed a massive dataset of more than 8,800 whole-genome HBV sequences to study "recombination"—a process where different strains of a virus swap genetic information to create new, hybrid variants. By using advanced computational tools, the team identified 288 unique recombination events and determined that hybrids of genotypes B and C are the most common globally. The study specifically identified recombination hotspots in the HBx and pre-Core regions of the viral genome, which are the areas most prone to these genetic exchanges.

Why is this important?

Chronic HBV infection is a major cause of severe liver disease, including cirrhosis and liver cancer. Because the virus has a high mutation and recombination rate, it is constantly evolving, which can impact how well vaccines and treatments work. This study demonstrates that recombination patterns are conserved across different genotypes, meaning the virus follows predictable "rules" when swapping genetic material. These swaps are often shaped by the need for the virus to maintain the correct folding of its proteins to remain functional.

How can this make a difference?

Understanding the rules that govern HBV evolution is vital for developing long-term public health strategies. By identifying the specific genome regions where the virus is most likely to change, scientists can better monitor the emergence of new strains that might be more dangerous or capable of evading current vaccines. These findings strengthen global genomic surveillance efforts and help ensure that diagnostic tools and therapies remain effective against an ever-changing pathogen.

Derek Tshiabuila, James E. San, Eduan Wilkinson, Graeme Dor, Houriiyah Tegally, Tongai G. Maponga, Marion Delphin, Philippa C. Matthews, Darren P. Martin, Cheryl Baxter and Tulio de Oliveira, "Conserved recombination patterns across hepatitis B genotypes: a retrospective study." Virology Journal, (2025) 22:220. doi:10.1186/s12985-025-02829-0.