Genomic characterization of Mycobacterium tuberculosis lineage 7 and a proposed name: ‘Aethiops vetus’

Lineage 7 of the Mycobacterium tuberculosis complex has recently been identified among strains originating from Ethiopia. Using different DNA typing techniques, this study provides additional information on the genetic heterogeneity of five lineage 7 strains collected in the Amhara Region of Ethiopia. It also confirms the phylogenetic positioning of these strains between the ancient lineage 1 and TbD1-deleted, modern lineages 2, 3 and 4 of Mycobacterium tuberculosis. Four newly identified large sequence polymorphisms characteristic of the Amhara Region lineage 7 strains are described. While lineage 7 strains have been previously identified in the Woldiya area, we show that lineage 7 strains circulate in other parts of the Amhara Region and also among foreign-born individuals from Eritrea and Somalia in The Netherlands. For ease of documenting future identification of these strains in other geographical locations and recognizing the place of origin, we propose to assign lineage 7 strains the lineage name 'Aethiops vetus'.