Tracing the history of TB dispersal through global migration

News article 18 Oct 2018

LSTM’s Dr Maxine Caws is part of a team of researchers looking at how colonial migration and local adaptation have shaped the global expansion of a form of Mycobacterium tuberculosis, the bacterium that causes tuberculosis (TB).

TB is the single biggest infectious disease killer in the world and new strategies are needed to be able to stop it. Dr Maxine Caws said: “Between 2000 and 2015 33 million people died of TB. If we do not change what we do 28 million more people will die of TB between 2015 and 2030, at a cost to the global economy of 983 billion US dollars.”

Published in the journal Science Advancesthe paper, led by Dr Ola Brynildsrud of the Norwegian Institute of Public Health, the paper analyses the impact of historical global migrations on the dispersal of the most common linage of the bacterium, known as linage 4 or the Euro American linage. The paper shows how this lineage spread globally with the migration of European populations as they colonized Africa and the Americas between 1600 and 1900. The authors also looked at how the drug resistant forms of TB are spreading in this lineage. They looked for any evidence that modern migration patterns are reflected in the distribution of drug resistant strains of lineage 4 by comparing the DNA ‘fingerprints’ of a large collection of TB bacteria from around the world.

Encouragingly, no evidence was found of international spread of the drug resistant strains of the lineage of TB, which suggests that the multi-drug resistant forms, which are extremely hard to treat, can be contained with strong local Tb control programmes. In contrast, other studies have shown that the multi-drug resistant forms of another lineage of TB, known as lineage 2, or Beijing lineage, have spread internationally. Dr Caws added: “Ultimately, understanding how the underlying mechanisms responsible for these differences in the spread of lineage 2 and lineage 4 strains of the TB bacilli will help us to improve the effectiveness of our strategies to prevent the spread of drug resistant TB, and ultimately to eliminate it completely.”

Global expansion of Mycobacterium tuberculosis lineage 4 shaped by colonial migration and local adaptation

By Ola B. Brynildsrud, Caitlin S. Pepperell, Philip Suffys, Louis Grandjean, Johana Monteserin, Nadia Debech, Jon Bohlin, Kristian Alfsnes, John O.-H. Pettersson, Ingerid Kirkeleite, Fatima Fandinho, Marcia Aparecida Da Silva, Joao Perdigao, Isabel Portugal, Miguel Viveiros, Taane Clark, Maxine Caws, Sarah Dunstan, Phan Vuong Khac Thai, Beatriz Lopez, Viviana Ritacco, Andrew Kitchen, Tyler S. Brown, Dick Van Soolingen, Mary B. O’neill, Kathryn E. Holt, Edward J. Feil, Barun Mathema, Francois Balloux, Vegard Eldholm

Science Advances 17 Oct 2018 : Eaat5869