Phylogenetic evidence of extensive spatial mixing of diverse HIV-1 group M lineages within Cameroon but not between its neighbours

AI Summary

This research examined how different types of the main form of HIV‑1 (called group M) are spread within Cameroon and between Cameroon and its neighbouring countries in the Congo Basin. The team analysed samples taken from people living with HIV between 2000 and 2022 in both large cities and remote villages across Cameroon. They looked at genetic information from three parts of the virus to understand how diverse the virus types are and how they are related.

They found that HIV in Cameroon is very diverse. About half of the viruses belonged to one common type, but many other lineages were present, including a large number that don’t fit into the usual classification. The mix of virus types was similar throughout the country, whether in urban or rural areas.

When the researchers compared virus samples from Cameroon with those from nearby countries, they saw clear differences. Virus types tended to cluster by the country where they were found, suggesting that viruses spread freely within Cameroon but much less so across national borders. In other words, HIV moves around easily throughout Cameroon, but movement of specific virus lineages between neighbouring countries is limited.

The results suggest that the long history of HIV in Cameroon, combined with movement of people within the country, has led to a stable and highly mixed population of HIV types. However, different patterns of virus types in neighboring states indicate barriers to cross‑border spread.