Kigali: A new Tuberculosis strain, known as Lineage 8 (L8), was found by chance in Rwanda. This discovery is described as a “missing link” in the evolution of one of the world’s oldest and deadliest pathogens.
The findings are published in the Nature Communications yesterday, A Sister Lineage of Mycobacterium Tuberculosis Complex Discovered in the African Great Lakes Region. This follows another important research paper related to a problem in TB resistance detection just published in The Lancet Microbes.
Tuberculosis is one of the oldest pathogens to affect humans. It has several different strains or ‘lineages’. We have known about six lineages for over a decade and a seventh was discovered in Ethiopia about five years ago. Now scientists have found an eighth lineage in Rwanda and Uganda, which seems to be much older than the other lineages and could be a missing link in the evolution of what causes TB.
Remarkably, the strain is already resistant to key drugs in modern treatment (rifampicin and isoniazid), yet it seems to infect far fewer people than other strains and is seemingly restricted to the African Great Lakes region. Despite massive screening, no additional L8 strain was identified. The Rwandan strain is the sole viable L8 strain identified so far.
Jean-Claude Semuto NGABONZIZA, a researcher at the Rwanda Biomedical Center and PhD student at the Institute of Tropical Medicine, and the lead author on the paper, said: “Understanding this new lineage tells us more about how TB pathogen adapted to the human host and managed to spread worldwide. As this strain seems not to be spreading as much as other known TB strains, further and deeper studies of this strain will likely inform TB control and help towards finding effective vaccine and cure”.
This work resulted from close collaboration between the Rwanda Biomedical Centre (RBC), the Institute of Tropical Medicine in Belgium, the University of Bradford in UK, the Swiss Tropical and Public Health Institute in Switzerland, and the Centre National de Recherche Scientifique in France. (End)