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Study of tuberculosis in Africa reveals new lineage in the eastern part of the continent

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Study of tuberculosis in Africa reveals new lineage in the eastern part of the continent

Mireia Coscollá, researcher at the Institute of Integrative Systems Biology (I2SysBio), a mixed center at the University of Valencia and the CSIC. conducted a study on the bacteria that causes tuberculosis, one of the 10 deadliest diseases in the world, and in which it demonstrates the existence of a new lineage. After analyzing 675 African genomes, in an article published in the journal <i>Microbial Genomics</i> he concludes that the new lineage, named L9, is located mainly in the eastern part of the continent.</strong></p><p>The objective of this research has been to expand information on the genetics, phylogeography and evolutionary history of <em>M. africanum</em>, one of the groups into which bacteria of the species <em>Mycobacterium tuberculosis</em> are divided. This bacteria was the cause of more deaths than any other infectious disease until SARS-CoV-2 appeared, and is among the top ten causes of death worldwide, especially in sub-Saharan Africa. In this area, the most widespread lineages that cause this disease are lineage 5 (L5) and lineage 6 (L6), of which there is still not much information compared to the most widespread lineages in Europe, North America and Asia.</p><p>The novelty of the research, in which Paula Ruiz has also participated on behalf of I<sup>2</sup>SysBio, has come when, in addition to the expected lineages 5 and 6 of <em>M. africanum</em>, have discovered a new one that shares similarities with L6, but with a different geographical distribution from the rest of the African variants, in addition to a substantial genetic separation. This new variant, which they propose to call Lineage 9 (L9), is only present in samples originating in East Africa, while the vast majority of the L5 and L6 genomes came from West Africa and Central Africa.</p><p>Mireia Coscollá, Ramón y Cajal researcher, has highlighted the importance of genetic diversity studies of<em>M. africanum</em>, since a large part of the studies dedicated to this disease are focused on Europe and North America, while Africa is much less studied. He states: “a good understanding of the populations of any organism involves knowing all its populations, and even more so in the case of<em>M. tuberculosis</em> in Africa, where the infection caused by this pathogen hits very hard and cannot be ignored.”</p><p>Another objective of the research has been to use the genome to infer the resistance of the L5 sublineage to some antibiotics, an aspect that had been shown in previous studies with smaller and less diverse data sets, but that is not confirmed with more data. broad.</p><p>This research has had the support and financing of the Ramón y Cajal program of the Ministry of Science, Innovation and Universities, the European Society of Clinical Microbiology and Infectious Diseases (ESCMID), whose organization has awarded the research award to Mireia Coscollá; the Department of Education of the Generalitat Valenciana, the Swiss National Science Foundation, the European Research Council and Wellcome. </p><p> </p><p><strong>Article</strong>: <a href=Coscollá et al. «Phylogenomics of Mycobacterium africanum reveals a new lineage and a complex evolutionary history». Microbial Genomics 2021;7:000477. DOI: 10.1099/mgen.0.000477. 

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