Spread of Mycobacterium tuberculosis lineage 4 in South China influenced by Maritime Silk Road and “Huguang Filling Sichuan” population migration

Abstract

Background Lineage 4 of Mycobacterium tuberculosis complex (MTBC), mainly epidemic in Europe and Americas, presents in high proportions in South China and is believed to enter China around the 13th century, when the important human migratory events of the Maritime Silk Road and “Huguang Filling Sichuan” population migration happened in China. This study was to explain the coincidence of these two events with lineage 4’s high proportion in South China. Methods Based on the spatial interpolation analysis of the genotyping data of 25,575 MTBC isolates, the distribution of lineage 4 was compared with that of targeted surname populations and the Maritime Silk Road’s main ports. Results The results showed that lineage 4 distribution in China could be mapped to the regions affected by “Huguang Filling Sichuan” population migration; while the distribution of lineage 4’s two sub-lineages in Asia, Europe, Africa and Oceania could be best explained by the Maritime Silk Road. Conclusion Our results suggest that these two events might pose a crucial shared influence, leading to the greater incidence of lineage 4 in South China. And this may contribute to our better understanding of the prevailing tuberculosis landscape in China and facilitate the epidemiological investigations and tracking of emerging MTBC clones.